{"id":81405,"date":"2026-07-25T01:22:24","date_gmt":"2026-07-24T17:22:24","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/81405.html"},"modified":"2026-07-25T01:22:24","modified_gmt":"2026-07-24T17:22:24","slug":"11-%e5%8d%87%e7%ba%a7%e7%ae%80%e5%8d%95%e7%9a%84epoll%e4%bb%8e-select-%e5%88%b0-epoll%ef%bc%9ac17-tcp-%e6%9c%8d%e5%8a%a1%e5%99%a8%e7%9a%84%e5%85%ad%e5%b1%82%e6%b8%90%e8%bf%9b%e5%bc%8f%e9%87%8d","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/81405.html","title":{"rendered":"11.\u5347\u7ea7\u7b80\u5355\u7684Epoll,\u4ece select \u5230 epoll\uff1aC++17 TCP \u670d\u52a1\u5668\u7684\u516d\u5c42\u6e10\u8fdb\u5f0f\u91cd\u6784"},"content":{"rendered":"<\/p>\n<h4>\u6587\u7ae0\u76ee\u5f55<\/h4>\n<ul>\n<li>\u4ece select \u5230 epoll&#xff1a;C&#043;&#043;17 TCP \u670d\u52a1\u5668\u7684\u516d\u5c42\u6e10\u8fdb\u5f0f\u91cd\u6784<\/li>\n<li>\n<ul>\n<li>\u4e00\u3001\u4e3a\u4ec0\u4e48\u8981\u91c7\u7528\u201c\u5206\u5c42\u5347\u7ea7\u201d<\/li>\n<li>\u4e8c\u3001\u5148\u5efa\u7acb\u6b63\u786e\u7684 epoll \u5fc3\u667a\u6a21\u578b<\/li>\n<li>\n<ul>\n<li>2.1 epoll \u4e0d\u662f\u5f02\u6b65 I\/O<\/li>\n<li>2.2 interest list \u4e0e ready list<\/li>\n<li>2.3 epoll \u5e76\u4e0d\u662f\u201c\u5b8c\u5168\u96f6\u62f7\u8d1d\u201d<\/li>\n<li>2.4 \u4e0d\u8981\u628a epoll \u7684\u590d\u6742\u5ea6\u6982\u62ec\u6210\u201c\u6240\u6709\u64cd\u4f5c\u90fd\u662f O(1)\u201d<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u4e00\u90e8\u5206&#xff1a;\u7b2c 0 \u5c42\u2014\u2014\u539f\u59cb select \u7248\u672c<\/li>\n<li>\n<ul>\n<li>\u4e09\u3001\u7b2c 0 \u5c42\u7684\u76ee\u7684<\/li>\n<li>3.1 \u5b8c\u6574\u670d\u52a1\u7aef&#xff1a;&#096;00_select_original\/server.cpp&#096;<\/li>\n<li>3.2 \u5b8c\u6574\u5ba2\u6237\u7aef&#xff1a;&#096;00_select_original\/client.cpp&#096;<\/li>\n<li>3.3 \u539f\u59cb\u7248\u672c\u7684\u5177\u4f53\u95ee\u9898<\/li>\n<li>\n<ul>\n<li>\u95ee\u9898\u4e00&#xff1a;\u6bcf\u8f6e\u590d\u5236\u5e76\u4fee\u6539 fd_set<\/li>\n<li>\u95ee\u9898\u4e8c&#xff1a;\u8fd4\u56de\u540e\u4ecd\u7136\u904d\u5386\u5168\u90e8\u5ba2\u6237\u7aef<\/li>\n<li>\u95ee\u9898\u4e09&#xff1a;\u53d7\u5230 fd_set \u8868\u793a\u80fd\u529b\u9650\u5236<\/li>\n<li>\u95ee\u9898\u56db&#xff1a;\u628a EOF \u548c\u9519\u8bef\u6df7\u5728\u4e00\u8d77<\/li>\n<li>\u95ee\u9898\u4e94&#xff1a;\u9ed8\u8ba4\u963b\u585e I\/O<\/li>\n<li>\u95ee\u9898\u516d&#xff1a;\u6ca1\u6709\u5904\u7406\u90e8\u5206\u53d1\u9001<\/li>\n<li>\u95ee\u9898\u4e03&#xff1a;TCP \u6ca1\u6709\u6d88\u606f\u8fb9\u754c<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u4e8c\u90e8\u5206&#xff1a;\u7b2c 1 \u5c42\u2014\u2014\u6700\u5c0f epoll LT \u8fc1\u79fb<\/li>\n<li>\n<ul>\n<li>\u56db\u3001\u672c\u5c42\u76ee\u6807<\/li>\n<li>4.1 \u4ece select \u5230 epoll \u7684\u6700\u5c0f\u6620\u5c04<\/li>\n<li>4.2 \u5b8c\u6574\u670d\u52a1\u7aef&#xff1a;&#096;01_epoll_lt_minimal\/server.cpp&#096;<\/li>\n<li>4.3 \u5b8c\u6574\u5ba2\u6237\u7aef&#xff1a;&#096;01_epoll_lt_minimal\/client.cpp&#096;<\/li>\n<li>4.4 \u672c\u5c42\u4fee\u590d\u4e86\u4ec0\u4e48<\/li>\n<li>\n<ul>\n<li>\u4fee\u590d\u4e00&#xff1a;\u4e0d\u518d\u6bcf\u8f6e\u590d\u5236\u5b8c\u6574\u76d1\u63a7\u96c6\u5408<\/li>\n<li>\u4fee\u590d\u4e8c&#xff1a;\u4e0d\u518d\u904d\u5386\u6240\u6709\u7a7a\u95f2\u5ba2\u6237\u7aef<\/li>\n<li>\u4fee\u590d\u4e09&#xff1a;\u4e0d\u518d\u4f9d\u8d56 &#096;max_fd &#043; 1&#096;<\/li>\n<\/ul>\n<\/li>\n<li>4.5 \u672c\u5c42\u4ecd\u7136\u5b58\u5728\u7684\u95ee\u9898<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u4e09\u90e8\u5206&#xff1a;\u7b2c 2 \u5c42\u2014\u2014\u975e\u963b\u585e epoll LT<\/li>\n<li>\n<ul>\n<li>\u4e94\u3001\u4e3a\u4ec0\u4e48 LT \u4e5f\u5efa\u8bae\u4f7f\u7528\u975e\u963b\u585e\u5957\u63a5\u5b57<\/li>\n<li>5.1 \u672c\u5c42\u65b0\u589e\u7684\u89c4\u5219<\/li>\n<li>\n<ul>\n<li>\u89c4\u5219\u4e00&#xff1a;\u76d1\u542c fd \u975e\u963b\u585e<\/li>\n<li>\u89c4\u5219\u4e8c&#xff1a;\u901a\u4fe1 fd \u4e5f\u8bbe\u4e3a\u975e\u963b\u585e<\/li>\n<li>\u89c4\u5219\u4e09&#xff1a;\u5faa\u73af\u8bfb\u53d6\u5230 EAGAIN<\/li>\n<li>\u89c4\u5219\u56db&#xff1a;\u672c\u5c42\u9047\u5230\u53d1\u9001\u7f13\u51b2\u533a\u6ee1\u65f6\u76f4\u63a5\u5173\u95ed\u8fde\u63a5<\/li>\n<\/ul>\n<\/li>\n<li>5.2 \u5b8c\u6574\u670d\u52a1\u7aef&#xff1a;&#096;02_epoll_lt_nonblocking\/server.cpp&#096;<\/li>\n<li>5.3 \u5b8c\u6574\u5ba2\u6237\u7aef&#xff1a;&#096;02_epoll_lt_nonblocking\/client.cpp&#096;<\/li>\n<li>5.4 \u672c\u5c42\u4fee\u590d\u4e86\u4ec0\u4e48<\/li>\n<li>5.5 \u4e3a\u4ec0\u4e48\u4e0d\u80fd\u628a EAGAIN \u5f53\u6210\u9519\u8bef<\/li>\n<li>5.6 \u672c\u5c42\u4ecd\u7136\u5b58\u5728\u7684\u95ee\u9898<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u56db\u90e8\u5206&#xff1a;LT \u4e0e ET \u7684\u771f\u6b63\u533a\u522b<\/li>\n<li>\n<ul>\n<li>\u516d\u3001\u6c34\u5e73\u89e6\u53d1 LT<\/li>\n<li>\u4e03\u3001\u8fb9\u7f18\u89e6\u53d1 ET<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u4e94\u90e8\u5206&#xff1a;ET \u7684\u4e24\u4e2a\u5178\u578b\u9519\u8bef<\/li>\n<li>\n<ul>\n<li>\u516b\u3001\u9519\u8bef\u4e00&#xff1a;EPOLLET &#043; \u5355\u6b21 read<\/li>\n<li>\n<ul>\n<li>8.1 \u9519\u8bef\u903b\u8f91<\/li>\n<\/ul>\n<\/li>\n<li>8.2 \u5b8c\u6574\u9519\u8bef\u590d\u73b0\u4ee3\u7801<\/li>\n<li>\u4e5d\u3001\u9519\u8bef\u4e8c&#xff1a;EPOLLET &#043; \u963b\u585e\u5957\u63a5\u5b57 &#043; \u5faa\u73af read<\/li>\n<li>9.1 \u5b8c\u6574\u9519\u8bef\u590d\u73b0\u4ee3\u7801<\/li>\n<li>\u5341\u3001ET \u6b63\u786e\u8bfb\u6cd5<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u516d\u90e8\u5206&#xff1a;\u7b2c 3 \u5c42\u2014\u2014\u6b63\u786e\u7684 epoll ET \u8bfb\u53d6<\/li>\n<li>\n<ul>\n<li>\u5341\u4e00\u3001\u672c\u5c42\u76f8\u5bf9\u7b2c 2 \u5c42\u6539\u4e86\u4ec0\u4e48<\/li>\n<li>11.1 \u5b8c\u6574\u670d\u52a1\u7aef&#xff1a;&#096;03_epoll_et_correct_read\/server.cpp&#096;<\/li>\n<li>11.2 \u5b8c\u6574\u5ba2\u6237\u7aef&#xff1a;&#096;03_epoll_et_correct_read\/client.cpp&#096;<\/li>\n<li>11.3 \u672c\u5c42\u4fee\u590d\u4e86\u4ec0\u4e48<\/li>\n<li>11.4 \u672c\u5c42\u4ecd\u7136\u6ca1\u6709\u89e3\u51b3\u5199\u8def\u5f84<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u4e03\u90e8\u5206&#xff1a;\u4e3a\u4ec0\u4e48\u4e0d\u80fd\u6c38\u4e45\u76d1\u542c EPOLLOUT<\/li>\n<li>\n<ul>\n<li>\u5341\u4e8c\u3001\u5957\u63a5\u5b57\u201c\u53ef\u5199\u201d\u610f\u5473\u7740\u4ec0\u4e48<\/li>\n<li>\u5341\u4e09\u3001\u4e3a\u4ec0\u4e48\u6bcf\u4e2a\u8fde\u63a5\u90fd\u9700\u8981\u72ec\u7acb\u53d1\u9001\u72b6\u6001<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u516b\u90e8\u5206&#xff1a;\u7b2c 4 \u5c42\u2014\u2014ET &#043; \u53d1\u9001\u961f\u5217 &#043; EPOLLOUT<\/li>\n<li>\n<ul>\n<li>\u5341\u56db\u3001\u672c\u5c42\u65b0\u589e\u7684\u72b6\u6001\u673a<\/li>\n<li>14.1 \u5b8c\u6574\u670d\u52a1\u7aef&#xff1a;&#096;04_epoll_et_write_queue\/server.cpp&#096;<\/li>\n<li>14.2 \u5b8c\u6574\u5ba2\u6237\u7aef&#xff1a;&#096;04_epoll_et_write_queue\/client.cpp&#096;<\/li>\n<li>14.3 &#096;BuildClientEvents()&#096; \u7684\u610f\u4e49<\/li>\n<li>14.4 \u4e3a\u4ec0\u4e48\u6536\u5230\u6570\u636e\u540e\u5148\u4e3b\u52a8\u53d1\u9001<\/li>\n<li>14.5 &#096;EPOLLRDHUP&#096; \u4e0d\u80fd\u76f4\u63a5\u7b49\u540c\u4e8e\u201c\u6240\u6709\u6570\u636e\u5df2\u7ecf\u8bfb\u5b8c\u201d<\/li>\n<li>14.6 \u672c\u5c42\u4fee\u590d\u4e86\u4ec0\u4e48<\/li>\n<li>14.7 \u672c\u5c42\u7684\u65b0\u98ce\u9669&#xff1a;\u5185\u5b58\u65e0\u9650\u589e\u957f<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u4e5d\u90e8\u5206&#xff1a;\u80cc\u538b\u662f\u4ec0\u4e48<\/li>\n<li>\n<ul>\n<li>\u5341\u4e94\u3001\u80cc\u538b\u7684\u6838\u5fc3\u542b\u4e49<\/li>\n<li>\u5341\u516d\u3001\u9ad8\u4f4e\u6c34\u4f4d<\/li>\n<li>\u5341\u4e03\u3001\u4e3a\u4ec0\u4e48\u8fd8\u9700\u8981\u786c\u4e0a\u9650<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u5341\u90e8\u5206&#xff1a;ET\u3001\u516c\u5e73\u9884\u7b97\u548c EPOLLONESHOT<\/li>\n<li>\n<ul>\n<li>\u5341\u516b\u3001\u4e3a\u4ec0\u4e48\u4e0d\u80fd\u65e0\u9650\u6392\u7a7a\u4e00\u4e2a\u975e\u5e38\u6d3b\u8dc3\u7684\u8fde\u63a5<\/li>\n<li>\u5341\u4e5d\u3001ET \u4e0b\u63d0\u524d\u505c\u6b62\u8bfb\u53d6\u4e3a\u4ec0\u4e48\u5371\u9669<\/li>\n<li>\u4e8c\u5341\u3001EPOLLONESHOT \u7684\u8bed\u4e49<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u5341\u4e00\u90e8\u5206&#xff1a;\u7b2c 5 \u5c42\u2014\u2014\u80cc\u538b\u3001\u9884\u7b97\u4e0e\u8d44\u6e90\u8fb9\u754c<\/li>\n<li>\n<ul>\n<li>\u4e8c\u5341\u4e00\u3001\u6700\u7ec8\u5c42\u7684\u72b6\u6001\u5b57\u6bb5<\/li>\n<li>21.1 \u5b8c\u6574\u670d\u52a1\u7aef&#xff1a;&#096;05_epoll_et_backpressure\/server.cpp&#096;<\/li>\n<li>21.2 \u5b8c\u6574\u5ba2\u6237\u7aef&#xff1a;&#096;05_epoll_et_backpressure\/client.cpp&#096;<\/li>\n<li>21.3 \u6700\u7ec8\u5c42\u7684\u4fdd\u62a4\u673a\u5236<\/li>\n<li>\n<ul>\n<li>\u8fde\u63a5\u6570\u4e0a\u9650<\/li>\n<li>\u5355\u8fde\u63a5\u53d1\u9001\u961f\u5217\u786c\u4e0a\u9650<\/li>\n<li>\u9ad8\u4f4e\u6c34\u4f4d\u80cc\u538b<\/li>\n<li>\u6bcf\u4e8b\u4ef6\u8bfb\u5199\u9884\u7b97<\/li>\n<li>EPOLLONESHOT \u91cd\u88c5<\/li>\n<\/ul>\n<\/li>\n<li>21.4 \u6700\u7ec8\u5c42\u5b8c\u6574\u6d41\u7a0b\u56fe<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u5341\u4e8c\u90e8\u5206&#xff1a;epoll \u4e09\u5927 API \u9010\u9879\u89e3\u6790<\/li>\n<li>\n<ul>\n<li>\u4e8c\u5341\u4e8c\u3001&#096;epoll_create1()&#096;<\/li>\n<li>\u4e8c\u5341\u4e09\u3001&#096;epoll_ctl()&#096;<\/li>\n<li>\n<ul>\n<li>ADD<\/li>\n<li>MOD<\/li>\n<li>DEL<\/li>\n<\/ul>\n<\/li>\n<li>\u4e8c\u5341\u56db\u3001&#096;epoll_wait()&#096;<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u5341\u4e09\u90e8\u5206&#xff1a;\u5e38\u7528\u4e8b\u4ef6\u6807\u5fd7<\/li>\n<li>\n<ul>\n<li>\u4e8c\u5341\u4e94\u3001\u4e8b\u4ef6\u4f4d\u901f\u67e5\u8868<\/li>\n<li>\u4e8c\u5341\u516d\u3001\u4e3a\u4ec0\u4e48\u4f7f\u7528 SO_ERROR<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u5341\u56db\u90e8\u5206&#xff1a;accept\u3001recv\u3001send \u7684\u5b8c\u6574\u72b6\u6001\u8868<\/li>\n<li>\n<ul>\n<li>\u4e8c\u5341\u4e03\u3001\u975e\u963b\u585e accept<\/li>\n<li>\u4e8c\u5341\u516b\u3001\u975e\u963b\u585e recv<\/li>\n<li>\u4e8c\u5341\u4e5d\u3001\u975e\u963b\u585e send<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u5341\u4e94\u90e8\u5206&#xff1a;TCP \u534a\u5173\u95ed<\/li>\n<li>\n<ul>\n<li>\u4e09\u5341\u3001&#096;shutdown(SHUT_WR)&#096; \u7684\u610f\u4e49<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u5341\u516d\u90e8\u5206&#xff1a;LT \u4e0e ET \u5e94\u8be5\u5982\u4f55\u9009<\/li>\n<li>\n<ul>\n<li>\u4e09\u5341\u4e00\u3001\u5bf9\u6bd4\u8868<\/li>\n<li>\u4e09\u5341\u4e8c\u3001ET \u4e00\u5b9a\u6bd4 LT \u5feb\u5417<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u5341\u4e03\u90e8\u5206&#xff1a;\u538b\u529b\u6d4b\u8bd5\u5ba2\u6237\u7aef<\/li>\n<li>\n<ul>\n<li>\u4e09\u5341\u4e09\u3001\u5b8c\u6574\u5927\u6570\u636e\u6821\u9a8c\u5ba2\u6237\u7aef<\/li>\n<li>33.1 \u6d4b\u8bd5 1 MiB \u56de\u663e<\/li>\n<li>33.2 \u4e3a\u4ec0\u4e48\u4e0d\u80fd\u7528\u4e00\u6b21 write \u4f5c\u4e3a\u538b\u529b\u6d4b\u8bd5<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u5341\u516b\u90e8\u5206&#xff1a;\u7f16\u8bd1\u4e0e\u8fd0\u884c<\/li>\n<li>\n<ul>\n<li>\u4e09\u5341\u56db\u3001\u7f16\u8bd1\u5168\u90e8\u7248\u672c<\/li>\n<li>\u4e09\u5341\u4e94\u3001\u8fd0\u884c\u6307\u5b9a\u5c42\u6b21<\/li>\n<li>\n<ul>\n<li>\u7b2c 0 \u5c42<\/li>\n<li>\u7b2c 1 \u5c42<\/li>\n<li>\u7b2c 2 \u5c42<\/li>\n<li>\u7b2c 3 \u5c42<\/li>\n<li>\u7b2c 4 \u5c42<\/li>\n<li>\u7b2c 5 \u5c42<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u5341\u4e5d\u90e8\u5206&#xff1a;\u8c03\u8bd5\u65b9\u6cd5<\/li>\n<li>\n<ul>\n<li>\u4e09\u5341\u516d\u3001\u4f7f\u7528 strace \u89c2\u5bdf\u4e8b\u4ef6\u5faa\u73af<\/li>\n<li>\u4e09\u5341\u4e03\u3001\u4f7f\u7528 ss \u67e5\u770b\u8fde\u63a5<\/li>\n<li>\u4e09\u5341\u516b\u3001\u6a21\u62df\u6162\u5ba2\u6237\u7aef<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u4e8c\u5341\u90e8\u5206&#xff1a;\u5e38\u89c1\u9519\u8bef\u6e05\u5355<\/li>\n<li>\n<ul>\n<li>\u4e09\u5341\u4e5d\u3001\u9519\u8bef&#xff1a;ET \u53ea\u52a0 EPOLLET&#xff0c;\u4e0d\u6539\u8bfb\u53d6\u65b9\u5f0f<\/li>\n<li>\u56db\u5341\u3001\u9519\u8bef&#xff1a;ET \u4f7f\u7528\u963b\u585e fd \u5faa\u73af\u8bfb<\/li>\n<li>\u56db\u5341\u4e00\u3001\u9519\u8bef&#xff1a;\u628a EAGAIN \u5f53\u6210\u8fde\u63a5\u5931\u8d25<\/li>\n<li>\u56db\u5341\u4e8c\u3001\u9519\u8bef&#xff1a;\u6c38\u4e45\u76d1\u542c EPOLLOUT<\/li>\n<li>\u56db\u5341\u4e09\u3001\u9519\u8bef&#xff1a;\u5ffd\u7565\u90e8\u5206\u53d1\u9001<\/li>\n<li>\u56db\u5341\u56db\u3001\u9519\u8bef&#xff1a;\u53d1\u9001\u961f\u5217\u6ca1\u6709\u4e0a\u9650<\/li>\n<li>\u56db\u5341\u4e94\u3001\u9519\u8bef&#xff1a;ET \u8bbe\u7f6e\u5904\u7406\u9884\u7b97\u4f46\u4e0d\u91cd\u65b0\u6fc0\u6d3b<\/li>\n<li>\u56db\u5341\u516d\u3001\u9519\u8bef&#xff1a;EPOLLRDHUP \u7acb\u5373 close<\/li>\n<li>\u56db\u5341\u4e03\u3001\u9519\u8bef&#xff1a;\u5728 &#096;epoll_event.data.ptr&#096; \u4e2d\u4fdd\u5b58\u88f8\u6307\u9488\u5374\u4e0d\u7ba1\u7406\u751f\u547d\u5468\u671f<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u4e8c\u5341\u4e00\u90e8\u5206&#xff1a;\u8fdb\u4e00\u6b65\u5de5\u7a0b\u5316\u65b9\u5411<\/li>\n<li>\n<ul>\n<li>\u56db\u5341\u516b\u3001\u5e94\u7528\u5c42\u534f\u8bae\u62c6\u5305<\/li>\n<li>\u56db\u5341\u4e5d\u3001\u5b9a\u65f6\u5668<\/li>\n<li>\u4e94\u5341\u3001\u4fe1\u53f7<\/li>\n<li>\u4e94\u5341\u4e00\u3001\u591a\u7ebf\u7a0b<\/li>\n<li>\u4e94\u5341\u4e8c\u3001\u8de8\u7ebf\u7a0b\u5524\u9192<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u4e8c\u5341\u4e8c\u90e8\u5206&#xff1a;FAQ<\/li>\n<li>\n<ul>\n<li>\u4e94\u5341\u4e09\u3001close \u524d\u5fc5\u987b EPOLL_CTL_DEL \u5417<\/li>\n<li>\u4e94\u5341\u56db\u3001accepted socket \u4f1a\u7ee7\u627f O_NONBLOCK \u5417<\/li>\n<li>\u4e94\u5341\u4e94\u3001EAGAIN \u548c EWOULDBLOCK \u662f\u5426\u76f8\u540c<\/li>\n<li>\u4e94\u5341\u516d\u3001LT \u53ef\u4ee5\u4f7f\u7528\u963b\u585e\u5957\u63a5\u5b57\u5417<\/li>\n<li>\u4e94\u5341\u4e03\u3001ET \u662f\u5426\u6bcf\u6b21\u90fd\u5fc5\u987b\u8bfb\u5230 EAGAIN<\/li>\n<li>\u4e94\u5341\u516b\u3001epoll \u53ef\u4ee5\u76d1\u63a7\u666e\u901a\u6587\u4ef6\u5417<\/li>\n<li>\u4e94\u5341\u4e5d\u3001epoll \u80fd\u66ff\u4ee3\u7ebf\u7a0b\u6c60\u5417<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u4e8c\u5341\u4e09\u90e8\u5206&#xff1a;\u516d\u5c42\u6f14\u8fdb\u603b\u7ed3<\/li>\n<li>\n<ul>\n<li>\u516d\u5341\u3001\u6bcf\u4e00\u5c42\u5230\u5e95\u5b66\u5230\u4e86\u4ec0\u4e48<\/li>\n<li>\n<ul>\n<li>\u7b2c 0 \u5c42&#xff1a;select<\/li>\n<li>\u7b2c 1 \u5c42&#xff1a;epoll LT \u6700\u5c0f\u8fc1\u79fb<\/li>\n<li>\u7b2c 2 \u5c42&#xff1a;\u975e\u963b\u585e LT<\/li>\n<li>\u7b2c 3 \u5c42&#xff1a;ET \u6b63\u786e\u8bfb\u53d6<\/li>\n<li>\u7b2c 4 \u5c42&#xff1a;\u5199\u4e8b\u4ef6\u72b6\u6001\u673a<\/li>\n<li>\u7b2c 5 \u5c42&#xff1a;\u5de5\u7a0b\u8fb9\u754c<\/li>\n<\/ul>\n<\/li>\n<li>\u516d\u5341\u4e00\u3001\u6700\u7ec8\u6838\u5fc3\u539f\u5219<\/li>\n<\/ul>\n<\/li>\n<li>\u9644\u5f55 A&#xff1a;\u6e90\u7801\u76ee\u5f55<\/li>\n<li>\u9644\u5f55 B&#xff1a;\u5b98\u65b9\u8d44\u6599\u540d\u79f0<\/li>\n<\/ul>\n<h2>\u4ece select \u5230 epoll&#xff1a;C&#043;&#043;17 TCP \u670d\u52a1\u5668\u7684\u516d\u5c42\u6e10\u8fdb\u5f0f\u91cd\u6784<\/h2>\n<p>\u5e73\u53f0&#xff1a;Linux \u8bed\u8a00\u6807\u51c6&#xff1a;C&#043;&#043;17 \u793a\u4f8b\u7c7b\u578b&#xff1a;\u5355\u7ebf\u7a0b TCP Echo \u670d\u52a1\u5668 \u6838\u5fc3\u76ee\u6807&#xff1a;\u4e0d\u662f\u4e00\u6b21\u6027\u7ed9\u51fa\u4e00\u4efd\u590d\u6742\u7684\u201c\u6700\u7ec8\u4ee3\u7801\u201d&#xff0c;\u800c\u662f\u4ece\u539f\u59cb select \u7a0b\u5e8f\u5f00\u59cb&#xff0c;\u4e00\u5c42\u4e00\u5c42\u5347\u7ea7\u5230\u5177\u5907\u975e\u963b\u585e I\/O\u3001ET \u6b63\u786e\u8bfb\u5199\u3001\u53d1\u9001\u961f\u5217\u3001\u80cc\u538b\u548c\u516c\u5e73\u6027\u63a7\u5236\u7684 epoll \u4e8b\u4ef6\u5faa\u73af\u3002<\/p>\n<hr \/>\n<h3>\u4e00\u3001\u4e3a\u4ec0\u4e48\u8981\u91c7\u7528\u201c\u5206\u5c42\u5347\u7ea7\u201d<\/h3>\n<p>\u5f88\u591a epoll \u6559\u7a0b\u5b58\u5728\u540c\u4e00\u4e2a\u95ee\u9898&#xff1a;<\/p>\n<li>\u5148\u5c55\u793a\u4e00\u4efd\u975e\u5e38\u7b80\u5355\u7684 select \u4ee3\u7801&#xff1b;<\/li>\n<li>\u4e0b\u4e00\u9875\u76f4\u63a5\u51fa\u73b0 EPOLLET\u3001\u975e\u963b\u585e\u3001unordered_map\u3001\u53d1\u9001\u7f13\u51b2\u533a\u3001EPOLLOUT\u3001EPOLLONESHOT&#xff1b;<\/li>\n<li>\u8bfb\u8005\u80fd\u770b\u61c2\u6bcf\u4e00\u884c\u8bed\u6cd5&#xff0c;\u5374\u65e0\u6cd5\u7406\u89e3\u6bcf\u4e00\u5904\u72b6\u6001\u4e3a\u4ec0\u4e48\u5b58\u5728\u3002<\/li>\n<p>\u672c\u6587\u4e0d\u91c7\u7528\u8fd9\u79cd\u8df3\u8dc3\u5f0f\u8bb2\u6cd5&#xff0c;\u800c\u662f\u56fa\u5b9a\u4e3a\u516d\u4e2a\u53ef\u4ee5\u72ec\u7acb\u7f16\u8bd1\u3001\u72ec\u7acb\u8fd0\u884c\u7684\u7248\u672c&#xff1a;<\/p>\n<table>\n<tr>\u5c42\u6b21\u7248\u672c\u672c\u5c42\u53ea\u89e3\u51b3\u7684\u6838\u5fc3\u95ee\u9898<\/tr>\n<tbody>\n<tr>\n<td>\u7b2c 0 \u5c42<\/td>\n<td>\u539f\u59cb select<\/td>\n<td>\u5efa\u7acb\u5bf9\u7167\u57fa\u7ebf<\/td>\n<\/tr>\n<tr>\n<td>\u7b2c 1 \u5c42<\/td>\n<td>\u6700\u5c0f epoll LT<\/td>\n<td>\u628a\u201c\u626b\u63cf\u5168\u90e8 fd\u201d\u6539\u6210\u201c\u53ea\u8fd4\u56de\u5c31\u7eea\u4e8b\u4ef6\u201d<\/td>\n<\/tr>\n<tr>\n<td>\u7b2c 2 \u5c42<\/td>\n<td>\u975e\u963b\u585e epoll LT<\/td>\n<td>\u6392\u7a7a\u8fde\u63a5\u961f\u5217\u3001\u533a\u5206 EAGAIN\u3001\u907f\u514d\u5355\u4e2a I\/O \u963b\u585e\u4e8b\u4ef6\u5faa\u73af<\/td>\n<\/tr>\n<tr>\n<td>\u7b2c 3 \u5c42<\/td>\n<td>\u6b63\u786e\u7684 epoll ET \u8bfb\u53d6<\/td>\n<td>\u975e\u963b\u585e\u5957\u63a5\u5b57 &#043; \u5faa\u73af\u5904\u7406\u5230 EAGAIN<\/td>\n<\/tr>\n<tr>\n<td>\u7b2c 4 \u5c42<\/td>\n<td>ET \u53d1\u9001\u961f\u5217<\/td>\n<td>\u5904\u7406\u90e8\u5206\u53d1\u9001\u3001\u53d1\u9001\u7f13\u51b2\u533a\u6ee1\u548c EPOLLOUT<\/td>\n<\/tr>\n<tr>\n<td>\u7b2c 5 \u5c42<\/td>\n<td>\u80cc\u538b\u4e0e\u516c\u5e73\u6027<\/td>\n<td>\u9650\u5236\u5185\u5b58\u3001\u6682\u505c\u8bfb\u53d6\u3001\u5904\u7406\u9884\u7b97\u3001EPOLLONESHOT \u91cd\u88c5<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u6bcf\u4e00\u5c42\u90fd\u5305\u542b&#xff1a;<\/p>\n<ul>\n<li>\u5b8c\u6574\u670d\u52a1\u7aef\u4ee3\u7801&#xff1b;<\/li>\n<li>\u5b8c\u6574\u5ba2\u6237\u7aef\u4ee3\u7801&#xff1b;<\/li>\n<li>\u76f8\u5bf9\u4e0a\u4e00\u5c42\u6539\u52a8\u4e86\u4ec0\u4e48&#xff1b;<\/li>\n<li>\u4fee\u590d\u4e86\u4ec0\u4e48&#xff1b;<\/li>\n<li>\u672c\u5c42\u4ecd\u7136\u6ca1\u6709\u89e3\u51b3\u4ec0\u4e48&#xff1b;<\/li>\n<li>\u7f16\u8bd1\u4e0e\u8fd0\u884c\u65b9\u6cd5\u3002<\/li>\n<\/ul>\n<hr \/>\n<h3>\u4e8c\u3001\u5148\u5efa\u7acb\u6b63\u786e\u7684 epoll \u5fc3\u667a\u6a21\u578b<\/h3>\n<h4>2.1 epoll \u4e0d\u662f\u5f02\u6b65 I\/O<\/h4>\n<p>epoll \u662f\u4e00\u79cd I\/O \u5c31\u7eea\u4e8b\u4ef6\u901a\u77e5\u673a\u5236\u3002<\/p>\n<p>\u5b83\u544a\u8bc9\u5e94\u7528\u7a0b\u5e8f&#xff1a;<\/p>\n<p>\u67d0\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26\u73b0\u5728\u53ef\u80fd\u53ef\u4ee5\u6267\u884c\u8bfb\u53d6\u3001\u5199\u5165\u6216\u5176\u4ed6\u64cd\u4f5c\u3002<\/p>\n<p>\u5b83\u4e0d\u4f1a\u66ff\u5e94\u7528\u7a0b\u5e8f\u6267\u884c recv() \u6216 send()&#xff0c;\u4e5f\u4e0d\u4f1a\u81ea\u52a8\u521b\u5efa\u7ebf\u7a0b\u3002<\/p>\n<p>\u5178\u578b\u6267\u884c\u8fc7\u7a0b\u4ecd\u7136\u662f\u540c\u6b65\u7684&#xff1a;<\/p>\n<p>\u5e94\u7528\u7ebf\u7a0b<br \/>\n   \u2502<br \/>\n   \u2502 epoll_wait()<br \/>\n   \u25bc<br \/>\n\u7b49\u5f85\u4e00\u4e2a\u6216\u591a\u4e2a fd \u5c31\u7eea<br \/>\n   \u2502<br \/>\n   \u2502 \u8fd4\u56de\u5c31\u7eea\u4e8b\u4ef6<br \/>\n   \u25bc<br \/>\n\u5e94\u7528\u81ea\u5df1\u8c03\u7528 recv()\/send()\/accept()<br \/>\n   \u2502<br \/>\n   \u25bc<br \/>\n\u5904\u7406\u4e1a\u52a1\u72b6\u6001<br \/>\n   \u2502<br \/>\n   \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2192 \u518d\u6b21 epoll_wait()<\/p>\n<p>\u6240\u4ee5\u66f4\u51c6\u786e\u7684\u63cf\u8ff0\u662f&#xff1a;<\/p>\n<p>epoll \u8d1f\u8d23\u201c\u544a\u8bc9\u4f60\u8c01\u53ef\u80fd\u80fd\u505a I\/O\u201d&#xff0c;\u5e94\u7528\u7a0b\u5e8f\u4ecd\u8d1f\u8d23\u771f\u6b63\u7684 I\/O \u548c\u72b6\u6001\u7ba1\u7406\u3002<\/p>\n<h4>2.2 interest list \u4e0e ready list<\/h4>\n<p>\u4ece\u7528\u6237\u6001\u89c6\u89d2&#xff0c;\u53ef\u4ee5\u628a\u4e00\u4e2a epoll \u5b9e\u4f8b\u7406\u89e3\u6210\u4e24\u90e8\u5206&#xff1a;<\/p>\n<p>                    epoll \u5b9e\u4f8b<br \/>\n        \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510<br \/>\n        \u2502                             \u2502<br \/>\n        \u2502  interest list             \u2502<br \/>\n        \u2502  \u6211\u5173\u5fc3\u54ea\u4e9b fd\u3001\u54ea\u4e9b\u4e8b\u4ef6     \u2502<br \/>\n        \u2502                             \u2502<br \/>\n        \u2502  fd&#061;3: EPOLLIN              \u2502<br \/>\n        \u2502  fd&#061;7: EPOLLIN|EPOLLRDHUP   \u2502<br \/>\n        \u2502  fd&#061;9: EPOLLIN|EPOLLOUT     \u2502<br \/>\n        \u2502                             \u2502<br \/>\n        \u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524<br \/>\n        \u2502                             \u2502<br \/>\n        \u2502  ready list                 \u2502<br \/>\n        \u2502  \u5f53\u524d\u5df2\u7ecf\u5c31\u7eea\u7684\u76d1\u63a7\u9879        \u2502<br \/>\n        \u2502                             \u2502<br \/>\n        \u2502  fd&#061;7: EPOLLIN              \u2502<br \/>\n        \u2502  fd&#061;9: EPOLLOUT             \u2502<br \/>\n        \u2502                             \u2502<br \/>\n        \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518<\/p>\n<p>\u4e09\u4e2a\u6838\u5fc3 API \u7684\u89d2\u8272\u5206\u522b\u662f&#xff1a;<\/p>\n<p>epoll_create1()<br \/>\n    \u521b\u5efa epoll \u5b9e\u4f8b<\/p>\n<p>epoll_ctl()<br \/>\n    \u4fee\u6539 interest list<br \/>\n    ADD \/ MOD \/ DEL<\/p>\n<p>epoll_wait()<br \/>\n    \u4ece ready list \u53d6\u51fa\u5f53\u524d\u5c31\u7eea\u4e8b\u4ef6<\/p>\n<h4>2.3 epoll \u5e76\u4e0d\u662f\u201c\u5b8c\u5168\u96f6\u62f7\u8d1d\u201d<\/h4>\n<p>select() \u6bcf\u8f6e\u90fd\u8981\u628a\u5f85\u76d1\u63a7\u7684 fd_set \u4f20\u7ed9\u5185\u6838&#xff0c;\u5e76\u5728\u8fd4\u56de\u65f6\u628a\u4fee\u6539\u540e\u7684\u96c6\u5408\u5e26\u56de\u7528\u6237\u6001\u3002<\/p>\n<p>epoll \u7684\u4f18\u52bf\u662f&#xff1a;<\/p>\n<ul>\n<li>\u76d1\u63a7\u96c6\u5408\u901a\u8fc7 epoll_ctl() \u6301\u4e45\u4fdd\u5b58\u5728\u5185\u6838\u4e2d&#xff1b;<\/li>\n<li>epoll_wait() \u4e0d\u9700\u8981\u6bcf\u8f6e\u91cd\u65b0\u63d0\u4ea4\u6574\u4e2a\u76d1\u63a7\u96c6\u5408&#xff1b;<\/li>\n<li>\u8fd4\u56de\u65f6\u53ea\u590d\u5236\u672c\u8f6e\u5c31\u7eea\u7684 epoll_event\u3002<\/li>\n<\/ul>\n<p>\u4f46 epoll_wait() \u8fd4\u56de\u4e8b\u4ef6\u65f6\u4ecd\u7136\u9700\u8981\u628a\u5c31\u7eea\u4e8b\u4ef6\u590d\u5236\u5230\u7528\u6237\u7f13\u51b2\u533a&#xff0c;\u6240\u4ee5\u4e0d\u5e94\u8be5\u628a epoll \u7b80\u5316\u6210\u201c\u96f6\u62f7\u8d1d\u201d\u3002<\/p>\n<h4>2.4 \u4e0d\u8981\u628a epoll \u7684\u590d\u6742\u5ea6\u6982\u62ec\u6210\u201c\u6240\u6709\u64cd\u4f5c\u90fd\u662f O(1)\u201d<\/h4>\n<p>\u66f4\u7a33\u59a5\u7684\u7406\u89e3\u662f&#xff1a;<\/p>\n<ul>\n<li>epoll_ctl() \u8981\u67e5\u8be2\u5e76\u4fee\u6539\u5185\u6838\u4e2d\u7684\u76d1\u63a7\u9879&#xff1b;<\/li>\n<li>epoll_wait() \u7684\u4e3b\u8981\u7528\u6237\u6001\u5904\u7406\u91cf\u4e0e\u8fd4\u56de\u7684\u5c31\u7eea\u4e8b\u4ef6\u6570\u91cf\u76f8\u5173&#xff1b;<\/li>\n<li>\u5e94\u7528\u4e0d\u518d\u50cf select() \u90a3\u6837\u7ebf\u6027\u68c0\u67e5\u6bcf\u4e00\u4e2a\u53ef\u80fd\u7684 fd&#xff1b;<\/li>\n<li>\u5185\u6838\u5b9e\u73b0\u7ec6\u8282\u53ef\u80fd\u968f\u7248\u672c\u6f14\u5316&#xff0c;\u4e0d\u5e94\u628a\u67d0\u4e00\u79cd\u5185\u90e8\u6570\u636e\u7ed3\u6784\u5f53\u4f5c\u7a33\u5b9a ABI\u3002<\/li>\n<\/ul>\n<hr \/>\n<h2>\u7b2c\u4e00\u90e8\u5206&#xff1a;\u7b2c 0 \u5c42\u2014\u2014\u539f\u59cb select \u7248\u672c<\/h2>\n<h3>\u4e09\u3001\u7b2c 0 \u5c42\u7684\u76ee\u7684<\/h3>\n<p>\u8fd9\u4e00\u5c42\u4e0d\u8ffd\u6c42\u5065\u58ee\u6027&#xff0c;\u53ea\u4fdd\u7559\u6700\u521d\u4ee3\u7801\u7684\u7ed3\u6784&#xff0c;\u7528\u4e8e\u56de\u7b54&#xff1a;<\/p>\n<p>\u4ece select \u8fc1\u79fb\u5230 epoll \u65f6&#xff0c;\u6700\u5148\u53d1\u751f\u53d8\u5316\u7684\u5230\u5e95\u662f\u4ec0\u4e48&#xff1f;<\/p>\n<p>\u539f\u59cb\u7248\u672c\u7684\u4e3b\u8981\u7ed3\u6784\u662f&#xff1a;<\/p>\n<p>master_fds \u4fdd\u5b58\u5168\u90e8\u76d1\u63a7\u5bf9\u8c61<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\nread_fds &#061; master_fds<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\nselect() \u4fee\u6539 read_fds<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\nFD_ISSET(listen_fd)<br \/>\n        \u2502<br \/>\n        \u251c\u2500 accept()<br \/>\n        \u2502<br \/>\n        \u2514\u2500 \u904d\u5386 clients<br \/>\n              \u2502<br \/>\n              \u2514\u2500 FD_ISSET(client_fd)<\/p>\n<h3>3.1 \u5b8c\u6574\u670d\u52a1\u7aef&#xff1a;00_select_original\/server.cpp<\/h3>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;arpa\/inet.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/select.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/socket.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unistd.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;algorithm&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstring&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;iostream&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;string&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;vector&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">using<\/span> <span class=\"token keyword\">namespace<\/span> std<span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token comment\">\/\/ 1. \u521b\u5efa TCP \u76d1\u542c\u5957\u63a5\u5b57<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">socket<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span> SOCK_STREAM<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        cerr <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;socket() failed&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> endl<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ 2. \u8bbe\u7f6e\u7aef\u53e3\u590d\u7528<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> opt <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">setsockopt<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> SOL_SOCKET<span class=\"token punctuation\">,<\/span> SO_REUSEADDR<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>opt<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>opt<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ 3. \u7ed1\u5b9a\u5730\u5740\u5e76\u76d1\u542c<\/span><br \/>\n    sockaddr_in addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    addr<span class=\"token punctuation\">.<\/span>sin_family <span class=\"token operator\">&#061;<\/span> AF_INET<span class=\"token punctuation\">;<\/span><br \/>\n    addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">.<\/span>s_addr <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htonl<\/span><span class=\"token punctuation\">(<\/span>INADDR_ANY<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    addr<span class=\"token punctuation\">.<\/span>sin_port <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htons<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">8888<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">bind<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">||<\/span><br \/>\n        <span class=\"token function\">listen<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> <span class=\"token number\">5<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        cerr <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;bind\/listen failed&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> endl<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;Server listening on port 8888&#8230;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> endl<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ 4. \u521d\u59cb\u5316 select \u76d1\u63a7\u96c6\u5408<\/span><br \/>\n    fd_set master_fds<span class=\"token punctuation\">;<\/span><br \/>\n    fd_set read_fds<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>master_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>master_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> max_fd <span class=\"token operator\">&#061;<\/span> fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>    vector<span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token operator\">&gt;<\/span> clients<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/\/ select \u4f1a\u4fee\u6539 fd_set&#xff0c;\u56e0\u6b64\u6bcf\u8f6e\u5fc5\u987b\u590d\u5236\u3002<\/span><br \/>\n        read_fds <span class=\"token operator\">&#061;<\/span> master_fds<span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">int<\/span> activity <span class=\"token operator\">&#061;<\/span><br \/>\n            <span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span>max_fd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>activity <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;select&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ 5. \u76d1\u542c\u5957\u63a5\u5b57\u53ef\u8bfb&#xff1a;\u63a5\u6536\u4e00\u4e2a\u65b0\u8fde\u63a5<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            sockaddr_in client_addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            socklen_t len <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>client_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">int<\/span> cfd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">accept<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                fd<span class=\"token punctuation\">,<\/span> <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>client_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>len<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>cfd <span class=\"token operator\">!&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">char<\/span> ip_str<span class=\"token punctuation\">[<\/span>INET_ADDRSTRLEN<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token function\">inet_ntop<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n                          <span class=\"token operator\">&amp;<\/span>client_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">,<\/span><br \/>\n                          ip_str<span class=\"token punctuation\">,<\/span><br \/>\n                          <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>ip_str<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;New connection from &#034;<\/span><br \/>\n                     <span class=\"token operator\">&lt;&lt;<\/span> ip_str <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;:&#039;<\/span><br \/>\n                     <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token function\">ntohs<\/span><span class=\"token punctuation\">(<\/span>client_addr<span class=\"token punctuation\">.<\/span>sin_port<span class=\"token punctuation\">)<\/span><br \/>\n                     <span class=\"token operator\">&lt;&lt;<\/span> endl<span class=\"token punctuation\">;<\/span><\/p>\n<p>                <span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>cfd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>master_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                max_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">max<\/span><span class=\"token punctuation\">(<\/span>max_fd<span class=\"token punctuation\">,<\/span> cfd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">push_back<\/span><span class=\"token punctuation\">(<\/span>cfd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ 6. \u7ebf\u6027\u904d\u5386\u6240\u6709\u5ba2\u6237\u7aef&#xff0c;\u68c0\u67e5\u54ea\u4e9b fd \u53ef\u8bfb<\/span><br \/>\n        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">auto<\/span> it <span class=\"token operator\">&#061;<\/span> clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">begin<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> it <span class=\"token operator\">!&#061;<\/span> clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">end<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">int<\/span> cfd <span class=\"token operator\">&#061;<\/span> <span class=\"token operator\">*<\/span>it<span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span>cfd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                string buf<span class=\"token punctuation\">;<\/span><br \/>\n                buf<span class=\"token punctuation\">.<\/span><span class=\"token function\">resize<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">64<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span>cfd<span class=\"token punctuation\">,<\/span> buf<span class=\"token punctuation\">.<\/span><span class=\"token function\">data<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> buf<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&lt;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;Client disconnected (fd&#061;&#034;<\/span><br \/>\n                         <span class=\"token operator\">&lt;&lt;<\/span> cfd <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;)&#039;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> endl<span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>cfd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token function\">FD_CLR<\/span><span class=\"token punctuation\">(<\/span>cfd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>master_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    it <span class=\"token operator\">&#061;<\/span> clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">erase<\/span><span class=\"token punctuation\">(<\/span>it<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    buf<span class=\"token punctuation\">.<\/span><span class=\"token function\">resize<\/span><span class=\"token punctuation\">(<\/span><span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;Received: &#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> buf <span class=\"token operator\">&lt;&lt;<\/span> endl<span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">const<\/span> string reply <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;Hello from server&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span>cfd<span class=\"token punctuation\">,<\/span> reply<span class=\"token punctuation\">.<\/span><span class=\"token function\">c_str<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> reply<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token operator\">&#043;&#043;<\/span>it<span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token operator\">&#043;&#043;<\/span>it<span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>3.2 \u5b8c\u6574\u5ba2\u6237\u7aef&#xff1a;00_select_original\/client.cpp<\/h3>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;arpa\/inet.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstring&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;iostream&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/socket.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unistd.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">using<\/span> <span class=\"token keyword\">namespace<\/span> std<span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token comment\">\/\/ 1. \u521b\u5efa TCP \u5957\u63a5\u5b57<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">socket<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span> SOCK_STREAM<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ 2. \u8bbe\u7f6e\u670d\u52a1\u5668\u5730\u5740<\/span><br \/>\n    sockaddr_in addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    addr<span class=\"token punctuation\">.<\/span>sin_family <span class=\"token operator\">&#061;<\/span> AF_INET<span class=\"token punctuation\">;<\/span><br \/>\n    addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">.<\/span>s_addr <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">inet_addr<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;127.0.0.1&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    addr<span class=\"token punctuation\">.<\/span>sin_port <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htons<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">8888<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ 3. \u8fde\u63a5\u670d\u52a1\u5668<\/span><br \/>\n    <span class=\"token function\">connect<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;Connected to server&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> endl<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ 4. \u53d1\u9001\u4e00\u6761\u6d88\u606f<\/span><br \/>\n    <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">char<\/span><span class=\"token operator\">*<\/span> msg <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;Hello from client&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> msg<span class=\"token punctuation\">,<\/span> <span class=\"token function\">strlen<\/span><span class=\"token punctuation\">(<\/span>msg<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;Sent: &#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> msg <span class=\"token operator\">&lt;&lt;<\/span> endl<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ 5. \u963b\u585e\u7b49\u5f85\u670d\u52a1\u5668\u56de\u590d<\/span><br \/>\n    <span class=\"token keyword\">char<\/span> buf<span class=\"token punctuation\">[<\/span><span class=\"token number\">64<\/span><span class=\"token punctuation\">]<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> buf<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buf<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;Received: &#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> buf <span class=\"token operator\">&lt;&lt;<\/span> endl<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>3.3 \u539f\u59cb\u7248\u672c\u7684\u5177\u4f53\u95ee\u9898<\/h3>\n<h4>\u95ee\u9898\u4e00&#xff1a;\u6bcf\u8f6e\u590d\u5236\u5e76\u4fee\u6539 fd_set<\/h4>\n<p>read_fds <span class=\"token operator\">&#061;<\/span> master_fds<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span>max_fd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>select() \u4f1a\u539f\u5730\u4fee\u6539 read_fds&#xff0c;\u6240\u4ee5\u5fc5\u987b\u4fdd\u7559 master_fds&#xff0c;\u5e76\u5728\u6bcf\u8f6e\u91cd\u65b0\u590d\u5236\u3002<\/p>\n<h4>\u95ee\u9898\u4e8c&#xff1a;\u8fd4\u56de\u540e\u4ecd\u7136\u904d\u5386\u5168\u90e8\u5ba2\u6237\u7aef<\/h4>\n<p>\u5373\u4f7f\u53ea\u6709\u4e00\u4e2a\u5ba2\u6237\u7aef\u6709\u6570\u636e&#xff0c;\u5e94\u7528\u4ecd\u7136\u4f1a\u68c0\u67e5 clients \u4e2d\u7684\u6bcf\u4e00\u4e2a fd&#xff1a;<\/p>\n<p><span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">auto<\/span> it <span class=\"token operator\">&#061;<\/span> clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">begin<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> it <span class=\"token operator\">!&#061;<\/span> clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">end<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>it<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">*<\/span>it<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/\/ &#8230;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h4>\u95ee\u9898\u4e09&#xff1a;\u53d7\u5230 fd_set \u8868\u793a\u80fd\u529b\u9650\u5236<\/h4>\n<p>\u5728\u5e38\u89c1 Linux\/glibc \u73af\u5883\u4e2d&#xff0c;fd_set \u7684\u5bb9\u91cf\u7531 FD_SETSIZE \u7ea6\u675f\u3002\u6587\u4ef6\u63cf\u8ff0\u7b26\u6570\u503c\u4e00\u65e6\u8d85\u51fa\u53ef\u8868\u793a\u8303\u56f4&#xff0c;\u7ee7\u7eed\u4f7f\u7528 FD_SET() \u4f1a\u5bfc\u81f4\u672a\u5b9a\u4e49\u884c\u4e3a\u3002<\/p>\n<h4>\u95ee\u9898\u56db&#xff1a;\u628a EOF \u548c\u9519\u8bef\u6df7\u5728\u4e00\u8d77<\/h4>\n<p><span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&lt;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token comment\">\/\/ &#8230;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u8fd9\u91cc\u6ca1\u6709\u533a\u5206&#xff1a;<\/p>\n<p>n &#061;&#061; 0   \u5bf9\u7aef\u6709\u5e8f\u5173\u95ed\u5199\u65b9\u5411&#xff0c;\u63a5\u6536\u7aef\u5230\u8fbe EOF<br \/>\nn &#061;&#061; -1  \u7cfb\u7edf\u8c03\u7528\u5931\u8d25&#xff0c;\u9700\u8981\u68c0\u67e5 errno<\/p>\n<h4>\u95ee\u9898\u4e94&#xff1a;\u9ed8\u8ba4\u963b\u585e I\/O<\/h4>\n<p>\u5373\u4f7f select() \u62a5\u544a\u5957\u63a5\u5b57\u53ef\u8bfb&#xff0c;\u540e\u7eed\u64cd\u4f5c\u4ecd\u53ef\u80fd\u56e0\u4e3a\u7ade\u6001\u3001\u9519\u8bef\u7684\u5faa\u73af\u65b9\u5f0f\u6216\u4e0d\u5b8c\u6574\u7684\u72b6\u6001\u5224\u65ad\u800c\u963b\u585e\u3002<\/p>\n<h4>\u95ee\u9898\u516d&#xff1a;\u6ca1\u6709\u5904\u7406\u90e8\u5206\u53d1\u9001<\/h4>\n<p><span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span>cfd<span class=\"token punctuation\">,<\/span> reply<span class=\"token punctuation\">.<\/span><span class=\"token function\">data<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> reply<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>TCP write()\/send() \u6210\u529f\u8fd4\u56de\u65f6&#xff0c;\u8fd4\u56de\u503c\u53ef\u80fd\u5c0f\u4e8e\u8bf7\u6c42\u53d1\u9001\u957f\u5ea6\u3002\u4e0d\u80fd\u628a\u201c\u4e00\u6b21\u8c03\u7528\u6210\u529f\u201d\u7406\u89e3\u4e3a\u201c\u5168\u90e8\u6570\u636e\u5df2\u7ecf\u53d1\u9001\u201d\u3002<\/p>\n<h4>\u95ee\u9898\u4e03&#xff1a;TCP \u6ca1\u6709\u6d88\u606f\u8fb9\u754c<\/h4>\n<p>\u4e00\u6b21 write() \u4e0d\u4fdd\u8bc1\u5bf9\u5e94\u5bf9\u7aef\u7684\u4e00\u6b21 read()&#xff1a;<\/p>\n<p>\u53d1\u9001\u7aef&#xff1a;<br \/>\nwrite(&#034;ABC&#034;)<br \/>\nwrite(&#034;DEF&#034;)<\/p>\n<p>\u63a5\u6536\u7aef\u53ef\u80fd\u770b\u5230&#xff1a;<br \/>\nread() -&gt; &#034;ABCDEF&#034;<\/p>\n<p>\u4e5f\u53ef\u80fd\u770b\u5230&#xff1a;<br \/>\nread() -&gt; &#034;AB&#034;<br \/>\nread() -&gt; &#034;CDE&#034;<br \/>\nread() -&gt; &#034;F&#034;<\/p>\n<hr \/>\n<h2>\u7b2c\u4e8c\u90e8\u5206&#xff1a;\u7b2c 1 \u5c42\u2014\u2014\u6700\u5c0f epoll LT \u8fc1\u79fb<\/h2>\n<h3>\u56db\u3001\u672c\u5c42\u76ee\u6807<\/h3>\n<p>\u8fd9\u4e00\u5c42\u53ea\u5b8c\u6210\u4e00\u4ef6\u4e8b&#xff1a;<\/p>\n<p>\u7528 epoll_create1()\u3001epoll_ctl()\u3001epoll_wait() \u66ff\u6362 fd_set \u548c select()\u3002<\/p>\n<p>\u4e3a\u4e86\u8ba9\u5dee\u5f02\u8db3\u591f\u6e05\u695a&#xff0c;\u672c\u5c42\u523b\u610f\u4fdd\u7559&#xff1a;<\/p>\n<ul>\n<li>\u963b\u585e\u5957\u63a5\u5b57&#xff1b;<\/li>\n<li>\u6bcf\u6b21\u53ea accept() \u4e00\u4e2a\u8fde\u63a5&#xff1b;<\/li>\n<li>\u6bcf\u6b21\u53ea read() \u4e00\u6b21&#xff1b;<\/li>\n<li>\u5355\u6b21 write()&#xff1b;<\/li>\n<li>\u6ca1\u6709\u53d1\u9001\u961f\u5217\u3002<\/li>\n<\/ul>\n<h3>4.1 \u4ece select \u5230 epoll \u7684\u6700\u5c0f\u6620\u5c04<\/h3>\n<table>\n<tr>selectepoll<\/tr>\n<tbody>\n<tr>\n<td>FD_ZERO()<\/td>\n<td>epoll_create1()<\/td>\n<\/tr>\n<tr>\n<td>FD_SET(fd)<\/td>\n<td>epoll_ctl(ADD, fd)<\/td>\n<\/tr>\n<tr>\n<td>\u4fee\u6539\u76d1\u63a7\u4e8b\u4ef6<\/td>\n<td>epoll_ctl(MOD, fd)<\/td>\n<\/tr>\n<tr>\n<td>FD_CLR(fd)<\/td>\n<td>epoll_ctl(DEL, fd)<\/td>\n<\/tr>\n<tr>\n<td>select()<\/td>\n<td>epoll_wait()<\/td>\n<\/tr>\n<tr>\n<td>\u904d\u5386\u5168\u90e8\u5ba2\u6237\u7aef<\/td>\n<td>\u53ea\u904d\u5386\u8fd4\u56de\u7684\u5c31\u7eea\u4e8b\u4ef6<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u6838\u5fc3\u5faa\u73af\u4ece&#xff1a;<\/p>\n<p>read_fds <span class=\"token operator\">&#061;<\/span> master_fds<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd <span class=\"token operator\">:<\/span> clients<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/\/ &#8230;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u53d8\u6210&#xff1a;<\/p>\n<p><span class=\"token keyword\">int<\/span> count <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">epoll_wait<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> count<span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>i<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> fd <span class=\"token operator\">&#061;<\/span> events<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token comment\">\/\/ fd \u5df2\u7ecf\u662f\u672c\u8f6e\u5c31\u7eea\u5bf9\u8c61<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>4.2 \u5b8c\u6574\u670d\u52a1\u7aef&#xff1a;01_epoll_lt_minimal\/server.cpp<\/h3>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;arpa\/inet.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/epoll.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/socket.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unistd.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cerrno&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstdio&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstring&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;iostream&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;string&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unordered_set&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;vector&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">namespace<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> <span class=\"token keyword\">uint16_t<\/span> kPort <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">8888<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> <span class=\"token keyword\">int<\/span> kBacklog <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">5<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> <span class=\"token keyword\">int<\/span> kMaxEvents <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">64<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t kBufferSize <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">64<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">bool<\/span> <span class=\"token function\">AddReadEvent<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> epoll_fd<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    epoll_event event<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    event<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span> EPOLLIN<span class=\"token punctuation\">;<\/span>       <span class=\"token comment\">\/\/ \u672a\u6307\u5b9a EPOLLET&#xff0c;\u9ed8\u8ba4\u662f LT<\/span><br \/>\n    event<span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd <span class=\"token operator\">&#061;<\/span> fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span> EPOLL_CTL_ADD<span class=\"token punctuation\">,<\/span> fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>event<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_ctl(ADD)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">void<\/span> <span class=\"token function\">CloseClient<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                 <span class=\"token keyword\">int<\/span> client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                 std<span class=\"token double-colon punctuation\">::<\/span>unordered_set<span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token operator\">&gt;<\/span><span class=\"token operator\">&amp;<\/span> clients<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token comment\">\/\/ \u5bf9\u4e8e\u5355\u7ebf\u7a0b\u7b80\u5355\u7a0b\u5e8f&#xff0c;close() \u6700\u7ec8\u4e5f\u4f1a\u8ba9\u5185\u6838\u79fb\u9664\u76d1\u63a7\u9879&#xff1b;<\/span><br \/>\n    <span class=\"token comment\">\/\/ \u663e\u5f0f DEL \u53ef\u4ee5\u8ba9\u7528\u6237\u6001\u751f\u547d\u5468\u671f\u66f4\u52a0\u6e05\u6670\u3002<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  EPOLL_CTL_DEL<span class=\"token punctuation\">,<\/span><br \/>\n                  client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n        errno <span class=\"token operator\">!&#061;<\/span> ENOENT <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n        errno <span class=\"token operator\">!&#061;<\/span> EBADF<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_ctl(DEL)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">erase<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> listen_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">socket<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span> SOCK_STREAM<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>listen_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;socket&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">int<\/span> reuse <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">setsockopt<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n                   SOL_SOCKET<span class=\"token punctuation\">,<\/span><br \/>\n                   SO_REUSEADDR<span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token operator\">&amp;<\/span>reuse<span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>reuse<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;setsockopt&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    sockaddr_in server_addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_family <span class=\"token operator\">&#061;<\/span> AF_INET<span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">.<\/span>s_addr <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htonl<\/span><span class=\"token punctuation\">(<\/span>INADDR_ANY<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_port <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htons<\/span><span class=\"token punctuation\">(<\/span>kPort<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">bind<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n             <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n             <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;bind&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">listen<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span> kBacklog<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;listen&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ epoll \u5b9e\u4f8b\u672c\u8eab\u4e5f\u662f\u4e00\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26\u3002<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> epoll_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">epoll_create1<\/span><span class=\"token punctuation\">(<\/span>EPOLL_CLOEXEC<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>epoll_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_create1&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">AddReadEvent<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span> listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>vector<span class=\"token operator\">&lt;<\/span>epoll_event<span class=\"token operator\">&gt;<\/span> <span class=\"token function\">ready_events<\/span><span class=\"token punctuation\">(<\/span>kMaxEvents<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>unordered_set<span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token operator\">&gt;<\/span> clients<span class=\"token punctuation\">;<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;epoll LT minimal server listening on 0.0.0.0:&#034;<\/span><br \/>\n              <span class=\"token operator\">&lt;&lt;<\/span> kPort <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">int<\/span> ready_count <span class=\"token operator\">&#061;<\/span><br \/>\n            <span class=\"token function\">epoll_wait<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                       ready_events<span class=\"token punctuation\">.<\/span><span class=\"token function\">data<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                       <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>ready_events<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                       <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>ready_count <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_wait&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ epoll_wait \u53ea\u8fd4\u56de\u672c\u8f6e\u5df2\u7ecf\u5c31\u7eea\u7684\u4e8b\u4ef6&#xff0c;\u4e0d\u518d\u904d\u5386\u5168\u90e8\u8fde\u63a5\u3002<\/span><br \/>\n        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> ready_count<span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>i<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">int<\/span> current_fd <span class=\"token operator\">&#061;<\/span> ready_events<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd<span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint32_t<\/span> events <span class=\"token operator\">&#061;<\/span> ready_events<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>events<span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>current_fd <span class=\"token operator\">&#061;&#061;<\/span> listen_fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token comment\">\/\/ \u4e3a\u4e86\u4fdd\u6301\u201c\u6700\u5c0f\u8fc1\u79fb\u201d&#xff0c;\u672c\u5c42\u4ecd\u7136\u53ea accept \u4e00\u6b21\u3002<\/span><br \/>\n                sockaddr_in client_addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                socklen_t client_len <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>client_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                <span class=\"token keyword\">int<\/span> client_fd <span class=\"token operator\">&#061;<\/span><br \/>\n                    <span class=\"token function\">accept<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n                           <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>client_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                           <span class=\"token operator\">&amp;<\/span>client_len<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>client_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;accept&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><\/p>\n<p>                <span class=\"token keyword\">char<\/span> ip<span class=\"token punctuation\">[<\/span>INET_ADDRSTRLEN<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token function\">inet_ntop<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n                          <span class=\"token operator\">&amp;<\/span>client_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">,<\/span><br \/>\n                          ip<span class=\"token punctuation\">,<\/span><br \/>\n                          <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>ip<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;connected: &#034;<\/span><br \/>\n                          <span class=\"token operator\">&lt;&lt;<\/span> ip <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;:&#039;<\/span><br \/>\n                          <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token function\">ntohs<\/span><span class=\"token punctuation\">(<\/span>client_addr<span class=\"token punctuation\">.<\/span>sin_port<span class=\"token punctuation\">)<\/span><br \/>\n                          <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;, fd&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> client_fd <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">AddReadEvent<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span> client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><\/p>\n<p>                clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">insert<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">bool<\/span> close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>events <span class=\"token operator\">&amp;<\/span> EPOLLIN<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">0U<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span>kBufferSize<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span>current_fd<span class=\"token punctuation\">,<\/span> buffer<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;received from fd&#061;&#034;<\/span><br \/>\n                              <span class=\"token operator\">&lt;&lt;<\/span> current_fd <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;: &#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    std<span class=\"token double-colon punctuation\">::<\/span>cout<span class=\"token punctuation\">.<\/span><span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">,<\/span> n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token comment\">\/\/ \u672c\u5c42\u523b\u610f\u4fdd\u7559\u201c\u5355\u6b21 write\u201d\u7684\u65e7\u7ed3\u6784\u3002<\/span><br \/>\n                    ssize_t sent <span class=\"token operator\">&#061;<\/span><br \/>\n                        <span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span>current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                              buffer<span class=\"token punctuation\">,<\/span><br \/>\n                              <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>sent <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;write&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;read&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>events <span class=\"token operator\">&amp;<\/span> <span class=\"token punctuation\">(<\/span>EPOLLERR <span class=\"token operator\">|<\/span> EPOLLHUP<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">0U<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>close_now<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;closed fd&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> current_fd <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token function\">CloseClient<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span> current_fd<span class=\"token punctuation\">,<\/span> clients<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> client_fd <span class=\"token operator\">:<\/span> clients<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>4.3 \u5b8c\u6574\u5ba2\u6237\u7aef&#xff1a;01_epoll_lt_minimal\/client.cpp<\/h3>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;arpa\/inet.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/socket.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unistd.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cerrno&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstdio&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstring&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;iostream&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;string&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">namespace<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">bool<\/span> <span class=\"token function\">SendAll<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">char<\/span><span class=\"token operator\">*<\/span> data<span class=\"token punctuation\">,<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t size<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>size_t offset <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span>offset <span class=\"token operator\">&lt;<\/span> size<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">send<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span><br \/>\n                         data <span class=\"token operator\">&#043;<\/span> offset<span class=\"token punctuation\">,<\/span><br \/>\n                         size <span class=\"token operator\">&#8211;<\/span> offset<span class=\"token punctuation\">,<\/span><br \/>\n                         MSG_NOSIGNAL<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            offset <span class=\"token operator\">&#043;&#061;<\/span> <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;send&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> socket_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">socket<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span> SOCK_STREAM<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>socket_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;socket&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    sockaddr_in server_addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_family <span class=\"token operator\">&#061;<\/span> AF_INET<span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_port <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htons<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">8888<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">inet_pton<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token string\">&#034;127.0.0.1&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token operator\">&amp;<\/span>server_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span>cerr <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;invalid server address\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">connect<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span><br \/>\n                <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;connect&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">const<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string message <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;Hello from epoll LT client&#034;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">SendAll<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span> message<span class=\"token punctuation\">.<\/span><span class=\"token function\">data<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> message<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;sent: &#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> message <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span><span class=\"token number\">256<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    ssize_t n<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">do<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span> buffer<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;received: &#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span>cout<span class=\"token punctuation\">.<\/span><span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">,<\/span> n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;server closed connection\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;recv&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> n <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span> <span class=\"token operator\">?<\/span> <span class=\"token number\">1<\/span> <span class=\"token operator\">:<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>4.4 \u672c\u5c42\u4fee\u590d\u4e86\u4ec0\u4e48<\/h3>\n<h4>\u4fee\u590d\u4e00&#xff1a;\u4e0d\u518d\u6bcf\u8f6e\u590d\u5236\u5b8c\u6574\u76d1\u63a7\u96c6\u5408<\/h4>\n<p>\u76d1\u63a7\u9879\u901a\u8fc7 epoll_ctl() \u52a0\u5165 epoll \u5b9e\u4f8b&#xff0c;\u4e4b\u540e\u7531\u5185\u6838\u7ef4\u62a4\u3002<\/p>\n<h4>\u4fee\u590d\u4e8c&#xff1a;\u4e0d\u518d\u904d\u5386\u6240\u6709\u7a7a\u95f2\u5ba2\u6237\u7aef<\/h4>\n<p>epoll_wait() \u76f4\u63a5\u8fd4\u56de\u672c\u8f6e\u5c31\u7eea\u4e8b\u4ef6\u6570\u7ec4&#xff1a;<\/p>\n<p><span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> ready_count<span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>i<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> current_fd <span class=\"token operator\">&#061;<\/span> ready_events<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h4>\u4fee\u590d\u4e09&#xff1a;\u4e0d\u518d\u4f9d\u8d56 max_fd &#043; 1<\/h4>\n<p>epoll_wait() \u4e0d\u9700\u8981\u6700\u5927 fd \u53c2\u6570\u3002<\/p>\n<h3>4.5 \u672c\u5c42\u4ecd\u7136\u5b58\u5728\u7684\u95ee\u9898<\/h3>\n<ul>\n<li>\u76d1\u542c\u5957\u63a5\u5b57\u4ecd\u7136\u963b\u585e&#xff1b;<\/li>\n<li>\u6bcf\u6b21\u76d1\u542c\u4e8b\u4ef6\u53ea accept() \u4e00\u4e2a\u8fde\u63a5&#xff1b;<\/li>\n<li>\u901a\u4fe1\u5957\u63a5\u5b57\u4ecd\u7136\u963b\u585e&#xff1b;<\/li>\n<li>\u6ca1\u6709\u6b63\u786e\u533a\u5206 EINTR\u3001EAGAIN&#xff1b;<\/li>\n<li>\u5355\u6b21 read() \u53ef\u80fd\u65e0\u6cd5\u8bfb\u5b8c\u5f53\u524d\u6570\u636e&#xff1b;<\/li>\n<li>\u5355\u6b21 write() \u53ef\u80fd\u90e8\u5206\u53d1\u9001&#xff1b;<\/li>\n<li>\u6ca1\u6709\u5904\u7406\u6162\u5ba2\u6237\u7aef&#xff1b;<\/li>\n<li>\u6ca1\u6709\u80cc\u538b\u3002<\/li>\n<\/ul>\n<p>\u56e0\u6b64\u672c\u5c42\u53ea\u662f\u201cAPI \u8fc1\u79fb\u7248\u201d&#xff0c;\u4e0d\u662f\u6700\u7ec8\u7248\u672c\u3002<\/p>\n<hr \/>\n<h2>\u7b2c\u4e09\u90e8\u5206&#xff1a;\u7b2c 2 \u5c42\u2014\u2014\u975e\u963b\u585e epoll LT<\/h2>\n<h3>\u4e94\u3001\u4e3a\u4ec0\u4e48 LT \u4e5f\u5efa\u8bae\u4f7f\u7528\u975e\u963b\u585e\u5957\u63a5\u5b57<\/h3>\n<p>LT \u6a21\u5f0f\u7684\u8bed\u4e49\u548c poll() \u63a5\u8fd1&#xff1a;\u53ea\u8981\u6761\u4ef6\u4ecd\u7136\u6ee1\u8db3&#xff0c;\u5c31\u53ef\u80fd\u7ee7\u7eed\u62a5\u544a\u5c31\u7eea\u3002<\/p>\n<p>\u8fd9\u5e76\u4e0d\u610f\u5473\u7740\u963b\u585e\u5957\u63a5\u5b57\u4e00\u5b9a\u5b89\u5168\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>epoll_wait \u62a5\u544a fd \u53ef\u8bfb<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\n\u53e6\u4e00\u4e2a\u6267\u884c\u5355\u5143\u5148\u8bfb\u8d70\u6570\u636e<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\n\u5f53\u524d\u7ebf\u7a0b\u8c03\u7528\u963b\u585e recv()<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\n\u53ef\u80fd\u7761\u7720\u7b49\u5f85\u65b0\u6570\u636e<\/p>\n<p>\u5728\u672c\u6587\u7684\u5355\u7ebf\u7a0b\u793a\u4f8b\u91cc\u8fd9\u79cd\u7ade\u6001\u8f83\u5c11&#xff0c;\u4f46\u7edf\u4e00\u91c7\u7528\u975e\u963b\u585e I\/O \u53ef\u4ee5\u5efa\u7acb\u66f4\u7a33\u5b9a\u7684\u4e8b\u4ef6\u5faa\u73af\u4e0d\u53d8\u91cf&#xff1a;<\/p>\n<p>\u4efb\u4f55\u53ef\u80fd\u7b49\u5f85\u7684\u7cfb\u7edf\u8c03\u7528&#xff0c;\u90fd\u5fc5\u987b\u4ee5 EAGAIN\/EWOULDBLOCK \u8fd4\u56de\u63a7\u5236\u6743&#xff0c;\u800c\u4e0d\u662f\u963b\u585e\u6574\u4e2a\u4e8b\u4ef6\u5faa\u73af\u3002<\/p>\n<h3>5.1 \u672c\u5c42\u65b0\u589e\u7684\u89c4\u5219<\/h3>\n<h4>\u89c4\u5219\u4e00&#xff1a;\u76d1\u542c fd \u975e\u963b\u585e<\/h4>\n<p>\u8fd9\u6837\u624d\u80fd\u5b89\u5168\u5730\u5faa\u73af accept()&#xff1a;<\/p>\n<p><span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> cfd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">accept<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>cfd <span class=\"token operator\">&gt;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u7ee7\u7eed accept<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EAGAIN <span class=\"token operator\">||<\/span><br \/>\n               errno <span class=\"token operator\">&#061;&#061;<\/span> EWOULDBLOCK<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h4>\u89c4\u5219\u4e8c&#xff1a;\u901a\u4fe1 fd \u4e5f\u8bbe\u4e3a\u975e\u963b\u585e<\/h4>\n<p>Linux \u4e0a&#xff0c;accept() \u5f97\u5230\u7684\u65b0\u5957\u63a5\u5b57\u4e0d\u4f1a\u56e0\u4e3a\u76d1\u542c\u5957\u63a5\u5b57\u8bbe\u7f6e\u4e86 O_NONBLOCK \u5c31\u81ea\u52a8\u7ee7\u627f\u8be5\u72b6\u6001&#xff0c;\u56e0\u6b64\u5fc5\u987b\u5355\u72ec\u8bbe\u7f6e&#xff0c;\u6216\u8005\u4f7f\u7528\u5e26 SOCK_NONBLOCK \u7684 accept4()\u3002<\/p>\n<h4>\u89c4\u5219\u4e09&#xff1a;\u5faa\u73af\u8bfb\u53d6\u5230 EAGAIN<\/h4>\n<p>LT \u5e76\u4e0d\u5f3a\u5236\u5fc5\u987b\u8fd9\u6837\u505a&#xff0c;\u4f46\u6392\u7a7a\u5f53\u524d\u63a5\u6536\u7f13\u51b2\u533a\u53ef\u4ee5\u51cf\u5c11\u91cd\u590d\u8fdb\u5165 epoll_wait()\u3002<\/p>\n<h4>\u89c4\u5219\u56db&#xff1a;\u672c\u5c42\u9047\u5230\u53d1\u9001\u7f13\u51b2\u533a\u6ee1\u65f6\u76f4\u63a5\u5173\u95ed\u8fde\u63a5<\/h4>\n<p>\u8fd9\u662f\u4e00\u4e2a\u6709\u610f\u4fdd\u7559\u7684\u4e2d\u95f4\u7b56\u7565&#xff1a;<\/p>\n<p>\u597d\u5904&#xff1a;\u4e0d\u4f1a\u963b\u585e\u4e8b\u4ef6\u5faa\u73af&#xff0c;\u4e5f\u4e0d\u4f1a\u6084\u6084\u4e22\u5f03\u672a\u53d1\u9001\u6570\u636e<br \/>\n\u4ee3\u4ef7&#xff1a;\u6162\u5ba2\u6237\u7aef\u4f1a\u88ab\u65ad\u5f00<\/p>\n<p>\u771f\u6b63\u4fdd\u7559\u6162\u5ba2\u6237\u7aef\u8fde\u63a5&#xff0c;\u9700\u8981\u5728\u7b2c 4 \u5c42\u5f15\u5165\u53d1\u9001\u961f\u5217\u3002<\/p>\n<h3>5.2 \u5b8c\u6574\u670d\u52a1\u7aef&#xff1a;02_epoll_lt_nonblocking\/server.cpp<\/h3>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;arpa\/inet.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;fcntl.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/epoll.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/socket.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unistd.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cerrno&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstdio&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;iostream&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unordered_set&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;vector&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">namespace<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> <span class=\"token keyword\">uint16_t<\/span> kPort <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">8888<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> <span class=\"token keyword\">int<\/span> kBacklog <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">128<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> <span class=\"token keyword\">int<\/span> kMaxEvents <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">64<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t kBufferSize <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">4096<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">bool<\/span> <span class=\"token function\">SetNonBlocking<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> old_flags <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> F_GETFL<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>old_flags <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span><br \/>\n                 F_SETFL<span class=\"token punctuation\">,<\/span><br \/>\n                 old_flags <span class=\"token operator\">|<\/span> O_NONBLOCK<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">bool<\/span> <span class=\"token function\">AddClient<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> epoll_fd<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">int<\/span> client_fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    epoll_event event<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    event<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span> EPOLLIN <span class=\"token operator\">|<\/span> EPOLLRDHUP<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u9ed8\u8ba4 LT<\/span><br \/>\n    event<span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd <span class=\"token operator\">&#061;<\/span> client_fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                     EPOLL_CTL_ADD<span class=\"token punctuation\">,<\/span><br \/>\n                     client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                     <span class=\"token operator\">&amp;<\/span>event<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">void<\/span> <span class=\"token function\">CloseClient<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                 <span class=\"token keyword\">int<\/span> client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                 std<span class=\"token double-colon punctuation\">::<\/span>unordered_set<span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token operator\">&gt;<\/span><span class=\"token operator\">&amp;<\/span> clients<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  EPOLL_CTL_DEL<span class=\"token punctuation\">,<\/span><br \/>\n                  client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n        errno <span class=\"token operator\">!&#061;<\/span> ENOENT <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n        errno <span class=\"token operator\">!&#061;<\/span> EBADF<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_ctl(DEL)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">erase<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;closed fd&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> client_fd <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token comment\">\/\/ \u672c\u5c42\u5c1a\u672a\u5f15\u5165\u53d1\u9001\u961f\u5217\u3002<\/span><br \/>\n<span class=\"token comment\">\/\/ \u4e3a\u907f\u514d\u975e\u963b\u585e send() \u963b\u585e\u4e8b\u4ef6\u5faa\u73af&#xff0c;\u5982\u679c\u4e0d\u80fd\u4e00\u6b21\u53d1\u9001\u5b8c&#xff0c;\u76f4\u63a5\u5173\u95ed\u8fde\u63a5\u3002<\/span><br \/>\n<span class=\"token keyword\">bool<\/span> <span class=\"token function\">SendImmediatelyOrFail<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span><br \/>\n                           <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">char<\/span><span class=\"token operator\">*<\/span> data<span class=\"token punctuation\">,<\/span><br \/>\n                           std<span class=\"token double-colon punctuation\">::<\/span>size_t size<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>size_t offset <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span>offset <span class=\"token operator\">&lt;<\/span> size<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">send<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span><br \/>\n                         data <span class=\"token operator\">&#043;<\/span> offset<span class=\"token punctuation\">,<\/span><br \/>\n                         size <span class=\"token operator\">&#8211;<\/span> offset<span class=\"token punctuation\">,<\/span><br \/>\n                         MSG_NOSIGNAL<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            offset <span class=\"token operator\">&#043;&#061;<\/span> <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n            <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EAGAIN <span class=\"token operator\">||<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EWOULDBLOCK<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            std<span class=\"token double-colon punctuation\">::<\/span>cerr<br \/>\n                <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;send buffer full; layer 02 has no output queue\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;send&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> listen_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">socket<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n                           SOCK_STREAM <span class=\"token operator\">|<\/span> SOCK_CLOEXEC<span class=\"token punctuation\">,<\/span><br \/>\n                           <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>listen_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;socket&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">SetNonBlocking<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;fcntl(listen_fd)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">int<\/span> reuse <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">setsockopt<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n                   SOL_SOCKET<span class=\"token punctuation\">,<\/span><br \/>\n                   SO_REUSEADDR<span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token operator\">&amp;<\/span>reuse<span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>reuse<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;setsockopt&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    sockaddr_in server_addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_family <span class=\"token operator\">&#061;<\/span> AF_INET<span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">.<\/span>s_addr <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htonl<\/span><span class=\"token punctuation\">(<\/span>INADDR_ANY<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_port <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htons<\/span><span class=\"token punctuation\">(<\/span>kPort<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">bind<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n             <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n             <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;bind&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">listen<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span> kBacklog<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;listen&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">int<\/span> epoll_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">epoll_create1<\/span><span class=\"token punctuation\">(<\/span>EPOLL_CLOEXEC<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>epoll_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_create1&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    epoll_event listen_event<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    listen_event<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span> EPOLLIN<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u9ed8\u8ba4 LT<\/span><br \/>\n    listen_event<span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd <span class=\"token operator\">&#061;<\/span> listen_fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  EPOLL_CTL_ADD<span class=\"token punctuation\">,<\/span><br \/>\n                  listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token operator\">&amp;<\/span>listen_event<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_ctl(ADD listen_fd)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>vector<span class=\"token operator\">&lt;<\/span>epoll_event<span class=\"token operator\">&gt;<\/span> <span class=\"token function\">ready_events<\/span><span class=\"token punctuation\">(<\/span>kMaxEvents<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>unordered_set<span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token operator\">&gt;<\/span> clients<span class=\"token punctuation\">;<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;epoll LT nonblocking server listening on 0.0.0.0:&#034;<\/span><br \/>\n              <span class=\"token operator\">&lt;&lt;<\/span> kPort <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">int<\/span> ready_count <span class=\"token operator\">&#061;<\/span><br \/>\n            <span class=\"token function\">epoll_wait<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                       ready_events<span class=\"token punctuation\">.<\/span><span class=\"token function\">data<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                       <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>ready_events<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                       <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>ready_count <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_wait&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> ready_count<span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>i<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">int<\/span> current_fd <span class=\"token operator\">&#061;<\/span> ready_events<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd<span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">uint32_t<\/span> events <span class=\"token operator\">&#061;<\/span> ready_events<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>events<span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>current_fd <span class=\"token operator\">&#061;&#061;<\/span> listen_fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token comment\">\/\/ \u76d1\u542c fd \u5df2\u7ecf\u975e\u963b\u585e&#xff0c;\u56e0\u6b64\u53ef\u4ee5\u4e00\u76f4 accept \u5230 EAGAIN\u3002<\/span><br \/>\n                <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    sockaddr_in client_addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    socklen_t client_len <span class=\"token operator\">&#061;<\/span><br \/>\n                        <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>client_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">int<\/span> client_fd <span class=\"token operator\">&#061;<\/span><br \/>\n                        <span class=\"token function\">accept<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n                               <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><br \/>\n                                   <span class=\"token operator\">&amp;<\/span>client_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                               <span class=\"token operator\">&amp;<\/span>client_len<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>client_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR <span class=\"token operator\">||<\/span><br \/>\n                            errno <span class=\"token operator\">&#061;&#061;<\/span> ECONNABORTED<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token punctuation\">}<\/span><\/p>\n<p>                        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EAGAIN <span class=\"token operator\">||<\/span><br \/>\n                            errno <span class=\"token operator\">&#061;&#061;<\/span> EWOULDBLOCK<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token punctuation\">}<\/span><\/p>\n<p>                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;accept&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">SetNonBlocking<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;fcntl(client_fd)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">AddClient<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span> client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_ctl(ADD client)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">char<\/span> ip<span class=\"token punctuation\">[<\/span>INET_ADDRSTRLEN<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token function\">inet_ntop<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n                              <span class=\"token operator\">&amp;<\/span>client_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">,<\/span><br \/>\n                              ip<span class=\"token punctuation\">,<\/span><br \/>\n                              <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>ip<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;connected: &#034;<\/span><br \/>\n                              <span class=\"token operator\">&lt;&lt;<\/span> ip <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;:&#039;<\/span><br \/>\n                              <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token function\">ntohs<\/span><span class=\"token punctuation\">(<\/span>client_addr<span class=\"token punctuation\">.<\/span>sin_port<span class=\"token punctuation\">)<\/span><br \/>\n                              <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;, fd&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> client_fd <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">insert<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><\/p>\n<p>                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">bool<\/span> close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>events <span class=\"token operator\">&amp;<\/span> EPOLLERR<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">0U<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">int<\/span> socket_error <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                socklen_t error_len <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>socket_error<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token function\">getsockopt<\/span><span class=\"token punctuation\">(<\/span>current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                           SOL_SOCKET<span class=\"token punctuation\">,<\/span><br \/>\n                           SO_ERROR<span class=\"token punctuation\">,<\/span><br \/>\n                           <span class=\"token operator\">&amp;<\/span>socket_error<span class=\"token punctuation\">,<\/span><br \/>\n                           <span class=\"token operator\">&amp;<\/span>error_len<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                std<span class=\"token double-colon punctuation\">::<\/span>cerr <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;socket error on fd&#061;&#034;<\/span><br \/>\n                          <span class=\"token operator\">&lt;&lt;<\/span> current_fd<br \/>\n                          <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;: errno&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> socket_error<br \/>\n                          <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>close_now <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n                <span class=\"token punctuation\">(<\/span>events <span class=\"token operator\">&amp;<\/span> EPOLLIN<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">0U<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token comment\">\/\/ \u5373\u4f7f LT \u4e0d\u5f3a\u5236\u6392\u7a7a&#xff0c;\u975e\u963b\u585e\u5faa\u73af\u8bfb\u53d6\u53ef\u4ee5\u51cf\u5c11\u91cd\u590d\u5524\u9192\u3002<\/span><br \/>\n                <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span>kBufferSize<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                                     buffer<span class=\"token punctuation\">,<\/span><br \/>\n                                     <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                                     <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;received &#034;<\/span><br \/>\n                                  <span class=\"token operator\">&lt;&lt;<\/span> n <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034; bytes from fd&#061;&#034;<\/span><br \/>\n                                  <span class=\"token operator\">&lt;&lt;<\/span> current_fd <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">SendImmediatelyOrFail<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                                current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                                buffer<span class=\"token punctuation\">,<\/span><br \/>\n                                <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                            close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token punctuation\">}<\/span><\/p>\n<p>                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EAGAIN <span class=\"token operator\">||<\/span><br \/>\n                        errno <span class=\"token operator\">&#061;&#061;<\/span> EWOULDBLOCK<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;recv&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>events <span class=\"token operator\">&amp;<\/span><br \/>\n                 <span class=\"token punctuation\">(<\/span>EPOLLRDHUP <span class=\"token operator\">|<\/span> EPOLLHUP<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">0U<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>close_now<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token function\">CloseClient<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                            current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                            clients<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> client_fd <span class=\"token operator\">:<\/span> clients<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>5.3 \u5b8c\u6574\u5ba2\u6237\u7aef&#xff1a;02_epoll_lt_nonblocking\/client.cpp<\/h3>\n<p>\u5ba2\u6237\u7aef\u4ecd\u7136\u4f7f\u7528 select() \u540c\u65f6\u76d1\u63a7&#xff1a;<\/p>\n<ul>\n<li>\u6807\u51c6\u8f93\u5165&#xff1b;<\/li>\n<li>\u670d\u52a1\u5668\u5957\u63a5\u5b57\u3002<\/li>\n<\/ul>\n<p>\u8fd9\u6837\u505a\u662f\u4e3a\u4e86\u628a\u672c\u7ae0\u7684\u53d8\u91cf\u9650\u5236\u5728\u670d\u52a1\u7aef epoll \u91cd\u6784\u4e0a&#xff0c;\u800c\u4e0d\u662f\u540c\u65f6\u6539\u53d8\u5ba2\u6237\u7aef\u6a21\u578b\u3002<\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;arpa\/inet.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/select.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/socket.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unistd.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cerrno&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstdio&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;iostream&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">namespace<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">bool<\/span> <span class=\"token function\">SendAll<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">char<\/span><span class=\"token operator\">*<\/span> data<span class=\"token punctuation\">,<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t size<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>size_t offset <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span>offset <span class=\"token operator\">&lt;<\/span> size<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">send<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span><br \/>\n                         data <span class=\"token operator\">&#043;<\/span> offset<span class=\"token punctuation\">,<\/span><br \/>\n                         size <span class=\"token operator\">&#8211;<\/span> offset<span class=\"token punctuation\">,<\/span><br \/>\n                         MSG_NOSIGNAL<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            offset <span class=\"token operator\">&#043;&#061;<\/span> <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;send&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> socket_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">socket<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span> SOCK_STREAM<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>socket_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;socket&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    sockaddr_in server_addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_family <span class=\"token operator\">&#061;<\/span> AF_INET<span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_port <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htons<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">8888<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">inet_pton<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token string\">&#034;127.0.0.1&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token operator\">&amp;<\/span>server_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span>cerr <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;invalid IPv4 address\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">connect<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span><br \/>\n                <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;connect&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;connected to 127.0.0.1:8888\\\\n&#034;<\/span><br \/>\n              <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;type text; Ctrl&#043;D stops sending but keeps receiving\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">bool<\/span> stdin_open <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        fd_set read_set<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>stdin_open<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>STDIN_FILENO<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">int<\/span> max_fd <span class=\"token operator\">&#061;<\/span> socket_fd <span class=\"token operator\">&gt;<\/span> STDIN_FILENO<br \/>\n                         <span class=\"token operator\">?<\/span> socket_fd<br \/>\n                         <span class=\"token operator\">:<\/span> STDIN_FILENO<span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">int<\/span> ready <span class=\"token operator\">&#061;<\/span><br \/>\n            <span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span>max_fd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>ready <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;select&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>stdin_open <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n            <span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span>STDIN_FILENO<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span><span class=\"token number\">4096<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span>STDIN_FILENO<span class=\"token punctuation\">,<\/span><br \/>\n                             buffer<span class=\"token punctuation\">,<\/span><br \/>\n                             <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">SendAll<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span><br \/>\n                             buffer<span class=\"token punctuation\">,<\/span><br \/>\n                             <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                stdin_open <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">shutdown<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span> SHUT_WR<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n                    errno <span class=\"token operator\">!&#061;<\/span> ENOTCONN<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;shutdown&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">!&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;read(stdin)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span><span class=\"token number\">4096<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span><br \/>\n                             buffer<span class=\"token punctuation\">,<\/span><br \/>\n                             <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                             <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span>cout<span class=\"token punctuation\">.<\/span><span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">,<\/span> n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span>cout<span class=\"token punctuation\">.<\/span><span class=\"token function\">flush<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;\\\\nserver closed connection\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">!&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;recv&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>5.4 \u672c\u5c42\u4fee\u590d\u4e86\u4ec0\u4e48<\/h3>\n<ul>\n<li>\u76d1\u542c\u5957\u63a5\u5b57\u4e0d\u518d\u56e0\u4e3a\u591a\u8c03\u7528\u4e00\u6b21 accept() \u800c\u963b\u585e&#xff1b;<\/li>\n<li>\u4e00\u6b21\u76d1\u542c\u4e8b\u4ef6\u53ef\u4ee5\u6392\u7a7a\u5f53\u524d\u5df2\u5b8c\u6210\u8fde\u63a5\u961f\u5217&#xff1b;<\/li>\n<li>\u901a\u4fe1\u5957\u63a5\u5b57\u4e0d\u518d\u8ba9\u4e8b\u4ef6\u5faa\u73af\u957f\u671f\u963b\u585e&#xff1b;<\/li>\n<li>\u6b63\u786e\u5904\u7406 EINTR&#xff1b;<\/li>\n<li>\u6b63\u786e\u5904\u7406 EAGAIN\/EWOULDBLOCK&#xff1b;<\/li>\n<li>\u4f7f\u7528 EPOLLRDHUP \u611f\u77e5\u5bf9\u7aef\u5173\u95ed\u5199\u65b9\u5411&#xff1b;<\/li>\n<li>\u4f7f\u7528 MSG_NOSIGNAL \u907f\u514d\u5411\u5df2\u5173\u95ed\u8fde\u63a5\u53d1\u9001\u6570\u636e\u65f6\u89e6\u53d1 SIGPIPE \u7ec8\u6b62\u8fdb\u7a0b&#xff1b;<\/li>\n<li>\u8bfb\u53d6\u8def\u5f84\u53ef\u4ee5\u4e00\u6b21\u5904\u7406\u5f53\u524d\u5df2\u7ecf\u5230\u8fbe\u7684\u591a\u6279\u6570\u636e\u3002<\/li>\n<\/ul>\n<h3>5.5 \u4e3a\u4ec0\u4e48\u4e0d\u80fd\u628a EAGAIN \u5f53\u6210\u9519\u8bef<\/h3>\n<p>\u975e\u963b\u585e\u5957\u63a5\u5b57\u4e2d&#xff1a;<\/p>\n<p>recv() &#061;&#061; -1<br \/>\nerrno &#061;&#061; EAGAIN \/ EWOULDBLOCK<\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>\u5f53\u524d\u6ca1\u6709\u66f4\u591a\u6570\u636e\u53ef\u4ee5\u7acb\u5373\u8bfb\u53d6&#xff0c;\u672c\u8f6e\u5904\u7406\u6b63\u5e38\u7ed3\u675f\u3002<\/p>\n<p>\u540c\u7406&#xff0c;\u975e\u963b\u585e send() \u8fd4\u56de EAGAIN \u8868\u793a&#xff1a;<\/p>\n<p>\u5f53\u524d\u53d1\u9001\u7f13\u51b2\u533a\u6682\u65f6\u6ca1\u6709\u8db3\u591f\u7a7a\u95f4&#xff0c;\u9700\u8981\u7a0d\u540e\u7b49\u5f85\u53ef\u5199\u4e8b\u4ef6\u3002<\/p>\n<p>\u5b83\u4eec\u662f\u4e8b\u4ef6\u9a71\u52a8\u7a0b\u5e8f\u4e2d\u7684\u6b63\u5e38\u63a7\u5236\u6d41&#xff0c;\u800c\u4e0d\u662f\u5f02\u5e38\u5d29\u6e83\u6761\u4ef6\u3002<\/p>\n<h3>5.6 \u672c\u5c42\u4ecd\u7136\u5b58\u5728\u7684\u95ee\u9898<\/h3>\n<p>\u672c\u5c42\u7684\u8bfb\u8def\u5f84\u5df2\u7ecf\u8f83\u7a33\u5065&#xff0c;\u4f46\u5199\u8def\u5f84\u4ecd\u7136\u91c7\u7528&#xff1a;<\/p>\n<p>\u7acb\u5373\u5199\u5b8c<br \/>\n    \u2502<br \/>\n    \u251c\u2500 \u6210\u529f&#xff1a;\u7ee7\u7eed<br \/>\n    \u2514\u2500 \u5199\u4e0d\u5b8c\/EAGAIN&#xff1a;\u5173\u95ed\u8fde\u63a5<\/p>\n<p>\u4e0b\u4e00\u6b65\u5207\u6362 ET \u65f6&#xff0c;\u5148\u4fdd\u6301\u8fd9\u4e2a\u9650\u5236\u4e0d\u53d8&#xff0c;\u53ea\u4e13\u6ce8\u89e3\u51b3 ET \u8bfb\u53d6\u89c4\u5219\u3002<\/p>\n<hr \/>\n<h2>\u7b2c\u56db\u90e8\u5206&#xff1a;LT \u4e0e ET \u7684\u771f\u6b63\u533a\u522b<\/h2>\n<h3>\u516d\u3001\u6c34\u5e73\u89e6\u53d1 LT<\/h3>\n<p>LT \u53ef\u4ee5\u7406\u89e3\u4e3a&#xff1a;<\/p>\n<p>\u53ea\u8981 fd \u5f53\u524d\u4ecd\u7136\u6ee1\u8db3\u5c31\u7eea\u6761\u4ef6&#xff0c;\u5c31\u53ef\u80fd\u7ee7\u7eed\u901a\u77e5\u3002<\/p>\n<p>\u5047\u8bbe\u63a5\u6536\u7f13\u51b2\u533a\u6709 5000 \u5b57\u8282&#xff0c;\u800c\u5e94\u7528\u6bcf\u6b21\u53ea\u8bfb 1024 \u5b57\u8282&#xff1a;<\/p>\n<p>\u7b2c 1 \u6b21 epoll_wait -&gt; EPOLLIN<br \/>\nread 1024&#xff0c;\u5269\u4f59 3976<\/p>\n<p>\u7b2c 2 \u6b21 epoll_wait -&gt; \u4ecd\u53ef\u80fd EPOLLIN<br \/>\nread 1024&#xff0c;\u5269\u4f59 2952<\/p>\n<p>\u2026\u2026<\/p>\n<h3>\u4e03\u3001\u8fb9\u7f18\u89e6\u53d1 ET<\/h3>\n<p>ET \u66f4\u63a5\u8fd1&#xff1a;<\/p>\n<p>\u5f53\u76d1\u63a7\u5bf9\u8c61\u7684\u5c31\u7eea\u72b6\u6001\u53d1\u751f\u53d8\u5316\u65f6\u901a\u77e5&#xff1b;\u6536\u5230\u901a\u77e5\u540e&#xff0c;\u5e94\u7528\u5e94\u628a\u8be5 fd \u5f53\u4f5c\u53ef\u64cd\u4f5c\u5bf9\u8c61\u5904\u7406&#xff0c;\u76f4\u5230\u975e\u963b\u585e I\/O \u8fd4\u56de EAGAIN\u3002<\/p>\n<p>\u6ce8\u610f&#xff0c;ET \u4e0d\u80fd\u88ab\u673a\u68b0\u5730\u7b80\u5316\u4e3a\u4e25\u683c\u7684\u201c\u7f13\u51b2\u533a\u4ece 0 \u5b57\u8282\u53d8\u6210\u975e 0 \u5b57\u8282\u53ea\u901a\u77e5\u4e00\u6b21\u201d\u3002\u591a\u4e2a\u6570\u636e\u5230\u8fbe\u8fc7\u7a0b\u4ecd\u53ef\u80fd\u4ea7\u751f\u591a\u4e2a\u4e8b\u4ef6\u3002\u771f\u6b63\u53ef\u9760\u7684\u7f16\u7a0b\u5951\u7ea6\u662f&#xff1a;<\/p>\n<p>\u6536\u5230 ET \u4e8b\u4ef6<br \/>\n    \u2502<br \/>\n    \u25bc<br \/>\n\u8ba4\u4e3a fd \u5f53\u524d\u53ef\u4ee5\u7ee7\u7eed\u5904\u7406<br \/>\n    \u2502<br \/>\n    \u25bc<br \/>\n\u975e\u963b\u585e read\/write \u5faa\u73af<br \/>\n    \u2502<br \/>\n    \u2514\u2500 \u76f4\u5230 EAGAIN \u624d\u628a\u63a7\u5236\u6743\u4ea4\u56de epoll_wait<\/p>\n<hr \/>\n<h2>\u7b2c\u4e94\u90e8\u5206&#xff1a;ET \u7684\u4e24\u4e2a\u5178\u578b\u9519\u8bef<\/h2>\n<h3>\u516b\u3001\u9519\u8bef\u4e00&#xff1a;EPOLLET &#043; \u5355\u6b21 read<\/h3>\n<h4>8.1 \u9519\u8bef\u903b\u8f91<\/h4>\n<p>event<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span> EPOLLIN <span class=\"token operator\">|<\/span> EPOLLET<span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token comment\">\/\/ \u6536\u5230\u4e8b\u4ef6\u540e\u53ea\u8bfb\u53d6\u4e00\u6b21<\/span><br \/>\n<span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> buffer<span class=\"token punctuation\">,<\/span> <span class=\"token number\">1024<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5047\u8bbe\u5ba2\u6237\u7aef\u53d1\u9001 5000 \u5b57\u8282&#xff1a;<\/p>\n<p>\u63a5\u6536\u7f13\u51b2\u533a<br \/>\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510<br \/>\n\u2502 \u524d 1024 \u5b57\u8282 \u2502 \u5269\u4f59 3976 \u5b57\u8282              \u2502<br \/>\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518<br \/>\n       \u25b2<br \/>\n       \u2514\u2500 \u5355\u6b21 read \u53ea\u53d6\u8d70\u8fd9\u91cc<\/p>\n<p>\u5269\u4f59\u6570\u636e\u5e76\u6ca1\u6709\u88ab\u5185\u6838\u201c\u4e22\u6389\u201d&#xff0c;\u800c\u662f\u4ecd\u7559\u5728\u63a5\u6536\u7f13\u51b2\u533a\u4e2d\u3002<\/p>\n<p>\u95ee\u9898\u5728\u4e8e&#xff1a;<\/p>\n<p>\u5e94\u7528\u5df2\u7ecf\u6d88\u8d39\u4e86\u8fd9\u4e00\u8f6e\u8fb9\u7f18\u901a\u77e5&#xff0c;\u5374\u6ca1\u6709\u628a\u5f53\u524d\u53ef\u8bfb\u72b6\u6001\u5904\u7406\u5b8c&#xff1b;\u4e4b\u540e\u53ef\u80fd\u957f\u65f6\u95f4\u6536\u4e0d\u5230\u65b0\u7684\u901a\u77e5\u3002<\/p>\n<p>\u6240\u4ee5\u66f4\u51c6\u786e\u7684\u672f\u8bed\u662f&#xff1a;<\/p>\n<ul>\n<li>\u672a\u8bfb\u6570\u636e\u6ede\u7559&#xff1b;<\/li>\n<li>\u8bfb\u53d6\u505c\u6ede&#xff1b;<\/li>\n<li>\u4e8b\u4ef6\u901a\u77e5\u9057\u6f0f\u540e\u7684\u5e94\u7528\u5c42\u9965\u997f\u3002<\/li>\n<\/ul>\n<p>\u4e0d\u5e94\u7b80\u5355\u79f0\u4e3a\u201cTCP \u6570\u636e\u4e22\u5931\u201d\u3002<\/p>\n<h3>8.2 \u5b8c\u6574\u9519\u8bef\u590d\u73b0\u4ee3\u7801<\/h3>\n<p>\u8be5\u4ee3\u7801\u53ea\u7528\u4e8e\u5b9e\u9a8c&#xff0c;\u4e0d\u5e94\u4f5c\u4e3a\u6b63\u786e\u5b9e\u73b0\u4f7f\u7528\u3002<\/p>\n<p><span class=\"token comment\">\/\/ \u9519\u8bef\u6f14\u793a&#xff1a;EPOLLET &#043; \u975e\u963b\u585e\u5957\u63a5\u5b57 &#043; \u5355\u6b21 read\u3002<\/span><br \/>\n<span class=\"token comment\">\/\/ \u7ed3\u679c\u4e0d\u662f\u201c\u5185\u6838\u4e22\u5305\u201d&#xff0c;\u800c\u662f\u672a\u8bfb\u6570\u636e\u53ef\u80fd\u957f\u671f\u7559\u5728\u63a5\u6536\u7f13\u51b2\u533a&#xff0c;<\/span><br \/>\n<span class=\"token comment\">\/\/ \u4e8b\u4ef6\u5faa\u73af\u5374\u4e0d\u4e00\u5b9a\u518d\u6b21\u6536\u5230\u901a\u77e5\u3002<\/span><\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;arpa\/inet.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;fcntl.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/epoll.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/socket.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unistd.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cerrno&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstdio&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;iostream&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">bool<\/span> <span class=\"token function\">SetNonBlocking<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> flags <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> F_GETFL<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> flags <span class=\"token operator\">!&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n           <span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> F_SETFL<span class=\"token punctuation\">,<\/span> flags <span class=\"token operator\">|<\/span> O_NONBLOCK<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> listen_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">socket<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span> SOCK_STREAM<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> reuse <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">setsockopt<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n               SOL_SOCKET<span class=\"token punctuation\">,<\/span><br \/>\n               SO_REUSEADDR<span class=\"token punctuation\">,<\/span><br \/>\n               <span class=\"token operator\">&amp;<\/span>reuse<span class=\"token punctuation\">,<\/span><br \/>\n               <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>reuse<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">SetNonBlocking<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    sockaddr_in addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    addr<span class=\"token punctuation\">.<\/span>sin_family <span class=\"token operator\">&#061;<\/span> AF_INET<span class=\"token punctuation\">;<\/span><br \/>\n    addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">.<\/span>s_addr <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htonl<\/span><span class=\"token punctuation\">(<\/span>INADDR_ANY<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    addr<span class=\"token punctuation\">.<\/span>sin_port <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htons<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">8888<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token function\">bind<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n         <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n         <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">listen<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span> <span class=\"token number\">128<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">int<\/span> epoll_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">epoll_create1<\/span><span class=\"token punctuation\">(<\/span>EPOLL_CLOEXEC<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    epoll_event listen_event<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    listen_event<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span> EPOLLIN <span class=\"token operator\">|<\/span> EPOLLET<span class=\"token punctuation\">;<\/span><br \/>\n    listen_event<span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd <span class=\"token operator\">&#061;<\/span> listen_fd<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n              EPOLL_CTL_ADD<span class=\"token punctuation\">,<\/span><br \/>\n              listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n              <span class=\"token operator\">&amp;<\/span>listen_event<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    epoll_event events<span class=\"token punctuation\">[<\/span><span class=\"token number\">16<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">int<\/span> count <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">epoll_wait<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                               events<span class=\"token punctuation\">,<\/span><br \/>\n                               <span class=\"token number\">16<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                               <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>count <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n            std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_wait&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> count<span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>i<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">int<\/span> fd <span class=\"token operator\">&#061;<\/span> events<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>fd <span class=\"token operator\">&#061;&#061;<\/span> listen_fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    <span class=\"token keyword\">int<\/span> client_fd <span class=\"token operator\">&#061;<\/span><br \/>\n                        <span class=\"token function\">accept<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n                               <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                               <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>client_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EAGAIN <span class=\"token operator\">||<\/span><br \/>\n                            errno <span class=\"token operator\">&#061;&#061;<\/span> EWOULDBLOCK<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token punctuation\">}<\/span><br \/>\n                        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token function\">SetNonBlocking<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    epoll_event client_event<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    client_event<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span><br \/>\n                        EPOLLIN <span class=\"token operator\">|<\/span> EPOLLET<span class=\"token punctuation\">;<\/span><br \/>\n                    client_event<span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd <span class=\"token operator\">&#061;<\/span> client_fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                              EPOLL_CTL_ADD<span class=\"token punctuation\">,<\/span><br \/>\n                              client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                              <span class=\"token operator\">&amp;<\/span>client_event<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span><span class=\"token number\">1024<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                <span class=\"token comment\">\/\/ \u9519\u8bef\u70b9&#xff1a;\u53ea\u8bfb\u53d6\u4e00\u6b21&#xff0c;\u6ca1\u6709\u6392\u7a7a\u5230 EAGAIN\u3002<\/span><br \/>\n                ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span><br \/>\n                                 buffer<span class=\"token punctuation\">,<\/span><br \/>\n                                 <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;single read returned &#034;<\/span><br \/>\n                          <span class=\"token operator\">&lt;&lt;<\/span> n <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034; bytes\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>\u4e5d\u3001\u9519\u8bef\u4e8c&#xff1a;EPOLLET &#043; \u963b\u585e\u5957\u63a5\u5b57 &#043; \u5faa\u73af read<\/h3>\n<p>\u6709\u4eba\u53d1\u73b0\u5355\u6b21\u8bfb\u53d6\u4e0d\u591f&#xff0c;\u4e8e\u662f\u6539\u6210&#xff1a;<\/p>\n<p><span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> buffer<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u4f46\u5982\u679c fd \u4ecd\u662f\u963b\u585e\u6a21\u5f0f&#xff1a;<\/p>\n<p>\u7b2c 1 \u6b21 read -&gt; 1024 \u5b57\u8282<br \/>\n\u7b2c 2 \u6b21 read -&gt; 1024 \u5b57\u8282<br \/>\n\u2026\u2026<br \/>\n\u6700\u540e\u4e00\u6279 read -&gt; \u6210\u529f<br \/>\n\u4e0b\u4e00\u6b21 read -&gt; \u63a5\u6536\u7f13\u51b2\u533a\u4e3a\u7a7a<br \/>\n                  \u2502<br \/>\n                  \u25bc<br \/>\n             \u5f53\u524d\u7ebf\u7a0b\u7761\u7720<br \/>\n                  \u2502<br \/>\n                  \u25bc<br \/>\n          \u6574\u4e2a\u4e8b\u4ef6\u5faa\u73af\u505c\u6b62\u5904\u7406\u5176\u4ed6 fd<\/p>\n<p>\u8fd9\u901a\u5e38\u4e0d\u662f\u4e25\u683c\u610f\u4e49\u4e0a\u7684\u201c\u6b7b\u9501\u201d&#xff0c;\u56e0\u4e3a\u65b0\u6570\u636e\u5230\u6765\u540e read() \u4ecd\u53ef\u80fd\u8fd4\u56de\u3002<\/p>\n<p>\u66f4\u51c6\u786e\u7684\u63cf\u8ff0\u662f&#xff1a;<\/p>\n<p>\u5355\u4e2a\u963b\u585e\u5957\u63a5\u5b57\u628a\u6574\u4e2a\u5355\u7ebf\u7a0b\u4e8b\u4ef6\u5faa\u73af\u957f\u671f\u5361\u4f4f&#xff0c;\u5176\u4ed6\u8fde\u63a5\u53d1\u751f\u9965\u997f\u3002<\/p>\n<h3>9.1 \u5b8c\u6574\u9519\u8bef\u590d\u73b0\u4ee3\u7801<\/h3>\n<p>\u8be5\u4ee3\u7801\u53ea\u7528\u4e8e\u5b9e\u9a8c&#xff0c;\u4e0d\u5e94\u4f5c\u4e3a\u6b63\u786e\u5b9e\u73b0\u4f7f\u7528\u3002<\/p>\n<p><span class=\"token comment\">\/\/ \u9519\u8bef\u6f14\u793a&#xff1a;EPOLLET &#043; \u963b\u585e\u901a\u4fe1\u5957\u63a5\u5b57 &#043; while(read)\u3002<\/span><br \/>\n<span class=\"token comment\">\/\/ \u5f53\u63a5\u6536\u7f13\u51b2\u533a\u88ab\u8bfb\u7a7a\u540e&#xff0c;\u4e0b\u4e00\u6b21 read \u4f1a\u963b\u585e\u6574\u4e2a\u4e8b\u4ef6\u5faa\u73af\u3002<\/span><br \/>\n<span class=\"token comment\">\/\/ \u8fd9\u4e0d\u662f\u4e25\u683c\u610f\u4e49\u4e0a\u7684\u201c\u6b7b\u9501\u201d&#xff0c;\u800c\u662f\u4e8b\u4ef6\u5faa\u73af\u88ab\u5355\u4e2a\u8fde\u63a5\u957f\u671f\u963b\u585e\u3002<\/span><\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;arpa\/inet.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;fcntl.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/epoll.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/socket.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unistd.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cerrno&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstdio&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;iostream&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">bool<\/span> <span class=\"token function\">SetNonBlocking<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> flags <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> F_GETFL<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> flags <span class=\"token operator\">!&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n           <span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> F_SETFL<span class=\"token punctuation\">,<\/span> flags <span class=\"token operator\">|<\/span> O_NONBLOCK<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> listen_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">socket<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span> SOCK_STREAM<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> reuse <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">setsockopt<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n               SOL_SOCKET<span class=\"token punctuation\">,<\/span><br \/>\n               SO_REUSEADDR<span class=\"token punctuation\">,<\/span><br \/>\n               <span class=\"token operator\">&amp;<\/span>reuse<span class=\"token punctuation\">,<\/span><br \/>\n               <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>reuse<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ \u76d1\u542c\u5957\u63a5\u5b57\u975e\u963b\u585e&#xff0c;\u65b9\u4fbf\u5faa\u73af accept\u3002<\/span><br \/>\n    <span class=\"token function\">SetNonBlocking<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    sockaddr_in addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    addr<span class=\"token punctuation\">.<\/span>sin_family <span class=\"token operator\">&#061;<\/span> AF_INET<span class=\"token punctuation\">;<\/span><br \/>\n    addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">.<\/span>s_addr <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htonl<\/span><span class=\"token punctuation\">(<\/span>INADDR_ANY<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    addr<span class=\"token punctuation\">.<\/span>sin_port <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htons<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">8888<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token function\">bind<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n         <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n         <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">listen<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span> <span class=\"token number\">128<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">int<\/span> epoll_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">epoll_create1<\/span><span class=\"token punctuation\">(<\/span>EPOLL_CLOEXEC<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    epoll_event listen_event<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    listen_event<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span> EPOLLIN <span class=\"token operator\">|<\/span> EPOLLET<span class=\"token punctuation\">;<\/span><br \/>\n    listen_event<span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd <span class=\"token operator\">&#061;<\/span> listen_fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n              EPOLL_CTL_ADD<span class=\"token punctuation\">,<\/span><br \/>\n              listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n              <span class=\"token operator\">&amp;<\/span>listen_event<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    epoll_event events<span class=\"token punctuation\">[<\/span><span class=\"token number\">16<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">int<\/span> count <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">epoll_wait<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                               events<span class=\"token punctuation\">,<\/span><br \/>\n                               <span class=\"token number\">16<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                               <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>count <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n            std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_wait&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> count<span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>i<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">int<\/span> fd <span class=\"token operator\">&#061;<\/span> events<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>fd <span class=\"token operator\">&#061;&#061;<\/span> listen_fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    <span class=\"token keyword\">int<\/span> client_fd <span class=\"token operator\">&#061;<\/span><br \/>\n                        <span class=\"token function\">accept<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n                               <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                               <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>client_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EAGAIN <span class=\"token operator\">||<\/span><br \/>\n                            errno <span class=\"token operator\">&#061;&#061;<\/span> EWOULDBLOCK<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token punctuation\">}<\/span><br \/>\n                        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token comment\">\/\/ \u9519\u8bef\u70b9&#xff1a;\u6ca1\u6709\u628a client_fd \u8bbe\u7f6e\u4e3a\u975e\u963b\u585e\u3002<\/span><br \/>\n                    epoll_event client_event<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    client_event<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span><br \/>\n                        EPOLLIN <span class=\"token operator\">|<\/span> EPOLLET<span class=\"token punctuation\">;<\/span><br \/>\n                    client_event<span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd <span class=\"token operator\">&#061;<\/span> client_fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                              EPOLL_CTL_ADD<span class=\"token punctuation\">,<\/span><br \/>\n                              client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                              <span class=\"token operator\">&amp;<\/span>client_event<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span><span class=\"token number\">1024<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    <span class=\"token comment\">\/\/ \u6570\u636e\u8bfb\u7a7a\u540e&#xff0c;\u8fd9\u91cc\u4f1a\u7761\u7720\u7b49\u5f85\u4e0b\u4e00\u6279\u6570\u636e&#xff0c;<\/span><br \/>\n                    <span class=\"token comment\">\/\/ \u4e8b\u4ef6\u5faa\u73af\u65e0\u6cd5\u5904\u7406\u5176\u4ed6 fd\u3002<\/span><br \/>\n                    ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span><br \/>\n                                     buffer<span class=\"token punctuation\">,<\/span><br \/>\n                                     <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&lt;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;read &#034;<\/span><br \/>\n                              <span class=\"token operator\">&lt;&lt;<\/span> n <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034; bytes\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>\u5341\u3001ET \u6b63\u786e\u8bfb\u6cd5<\/h3>\n<p>ET \u8bfb\u53d6\u8def\u5f84\u5e94\u4fdd\u6301\u4e09\u4e2a\u4e0d\u53d8\u91cf&#xff1a;<\/p>\n<p>1. fd \u5fc5\u987b\u662f\u975e\u963b\u585e\u6a21\u5f0f<br \/>\n2. \u6536\u5230\u53ef\u8bfb\u4e8b\u4ef6\u540e\u5faa\u73af recv()<br \/>\n3. \u53ea\u6709\u9047\u5230 EAGAIN\/EWOULDBLOCK \u624d\u7ed3\u675f\u672c\u8f6e\u8bfb\u53d6<\/p>\n<p>\u72b6\u6001\u8868&#xff1a;<\/p>\n<table>\n<tr>recv() \u7ed3\u679c\u542b\u4e49\u52a8\u4f5c<\/tr>\n<tbody>\n<tr>\n<td>n &gt; 0<\/td>\n<td>\u8bfb\u5230 n \u5b57\u8282<\/td>\n<td>\u5904\u7406\u6570\u636e&#xff0c;\u7ee7\u7eed\u8bfb<\/td>\n<\/tr>\n<tr>\n<td>n &#061;&#061; 0<\/td>\n<td>\u63a5\u6536\u65b9\u5411\u5230\u8fbe EOF<\/td>\n<td>\u6807\u8bb0\u5bf9\u7aef\u5199\u65b9\u5411\u5173\u95ed<\/td>\n<\/tr>\n<tr>\n<td>n &#061;&#061; -1, EINTR<\/td>\n<td>\u88ab\u4fe1\u53f7\u4e2d\u65ad<\/td>\n<td>\u91cd\u8bd5<\/td>\n<\/tr>\n<tr>\n<td>n &#061;&#061; -1, EAGAIN\/EWOULDBLOCK<\/td>\n<td>\u5f53\u524d\u5df2\u7ecf\u8bfb\u7a7a<\/td>\n<td>\u6b63\u5e38\u7ed3\u675f\u672c\u8f6e<\/td>\n<\/tr>\n<tr>\n<td>\u5176\u4ed6\u9519\u8bef<\/td>\n<td>\u8fde\u63a5\u5f02\u5e38<\/td>\n<td>\u5173\u95ed\u8fde\u63a5<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<h2>\u7b2c\u516d\u90e8\u5206&#xff1a;\u7b2c 3 \u5c42\u2014\u2014\u6b63\u786e\u7684 epoll ET \u8bfb\u53d6<\/h2>\n<h3>\u5341\u4e00\u3001\u672c\u5c42\u76f8\u5bf9\u7b2c 2 \u5c42\u6539\u4e86\u4ec0\u4e48<\/h3>\n<p>\u4ee3\u7801\u7ed3\u6784\u51e0\u4e4e\u4e0d\u53d8&#xff0c;\u5173\u952e\u5dee\u5f02\u53ea\u6709\u4e8b\u4ef6\u63a9\u7801&#xff1a;<\/p>\n<p><span class=\"token comment\">\/\/ LT<\/span><br \/>\nEPOLLIN <span class=\"token operator\">|<\/span> EPOLLRDHUP<\/p>\n<p><span class=\"token comment\">\/\/ ET<\/span><br \/>\nEPOLLIN <span class=\"token operator\">|<\/span> EPOLLRDHUP <span class=\"token operator\">|<\/span> EPOLLET<\/p>\n<p>\u56e0\u4e3a\u7b2c 2 \u5c42\u5df2\u7ecf\u5b8c\u6210&#xff1a;<\/p>\n<ul>\n<li>\u975e\u963b\u585e\u76d1\u542c fd&#xff1b;<\/li>\n<li>\u975e\u963b\u585e\u901a\u4fe1 fd&#xff1b;<\/li>\n<li>\u5faa\u73af accept() \u5230 EAGAIN&#xff1b;<\/li>\n<li>\u5faa\u73af recv() \u5230 EAGAIN&#xff1b;<\/li>\n<\/ul>\n<p>\u6240\u4ee5\u5207\u6362 ET \u4e0d\u9700\u8981\u4e00\u6b21\u6027\u91cd\u5199\u6574\u4e2a\u4e8b\u4ef6\u5faa\u73af\u3002<\/p>\n<p>\u8fd9\u6b63\u662f\u5206\u5c42\u5347\u7ea7\u7684\u4ef7\u503c\u3002<\/p>\n<h3>11.1 \u5b8c\u6574\u670d\u52a1\u7aef&#xff1a;03_epoll_et_correct_read\/server.cpp<\/h3>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;arpa\/inet.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;fcntl.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/epoll.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/socket.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unistd.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cerrno&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstdio&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;iostream&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unordered_set&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;vector&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">namespace<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> <span class=\"token keyword\">uint16_t<\/span> kPort <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">8888<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> <span class=\"token keyword\">int<\/span> kBacklog <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">128<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> <span class=\"token keyword\">int<\/span> kMaxEvents <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">64<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t kBufferSize <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">4096<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">bool<\/span> <span class=\"token function\">SetNonBlocking<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> old_flags <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> F_GETFL<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>old_flags <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span><br \/>\n                 F_SETFL<span class=\"token punctuation\">,<\/span><br \/>\n                 old_flags <span class=\"token operator\">|<\/span> O_NONBLOCK<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">bool<\/span> <span class=\"token function\">AddClient<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> epoll_fd<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">int<\/span> client_fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    epoll_event event<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    event<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span><br \/>\n        EPOLLIN <span class=\"token operator\">|<\/span> EPOLLRDHUP <span class=\"token operator\">|<\/span> EPOLLET<span class=\"token punctuation\">;<\/span><br \/>\n    event<span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd <span class=\"token operator\">&#061;<\/span> client_fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                     EPOLL_CTL_ADD<span class=\"token punctuation\">,<\/span><br \/>\n                     client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                     <span class=\"token operator\">&amp;<\/span>event<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">void<\/span> <span class=\"token function\">CloseClient<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                 <span class=\"token keyword\">int<\/span> client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                 std<span class=\"token double-colon punctuation\">::<\/span>unordered_set<span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token operator\">&gt;<\/span><span class=\"token operator\">&amp;<\/span> clients<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  EPOLL_CTL_DEL<span class=\"token punctuation\">,<\/span><br \/>\n                  client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n        errno <span class=\"token operator\">!&#061;<\/span> ENOENT <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n        errno <span class=\"token operator\">!&#061;<\/span> EBADF<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_ctl(DEL)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">erase<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;closed fd&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> client_fd <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token comment\">\/\/ \u672c\u5c42\u91cd\u70b9\u662f\u628a ET \u7684\u201c\u8bfb\u8def\u5f84\u201d\u505a\u6b63\u786e\u3002<\/span><br \/>\n<span class=\"token comment\">\/\/ \u5199\u8def\u5f84\u4ecd\u91c7\u7528\u201c\u5fc5\u987b\u7acb\u5373\u5168\u90e8\u5199\u5b8c&#xff0c;\u5426\u5219\u5173\u95ed\u8fde\u63a5\u201d\u7684\u7b80\u5316\u7b56\u7565\u3002<\/span><br \/>\n<span class=\"token keyword\">bool<\/span> <span class=\"token function\">SendImmediatelyOrFail<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span><br \/>\n                           <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">char<\/span><span class=\"token operator\">*<\/span> data<span class=\"token punctuation\">,<\/span><br \/>\n                           std<span class=\"token double-colon punctuation\">::<\/span>size_t size<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>size_t offset <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span>offset <span class=\"token operator\">&lt;<\/span> size<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">send<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span><br \/>\n                         data <span class=\"token operator\">&#043;<\/span> offset<span class=\"token punctuation\">,<\/span><br \/>\n                         size <span class=\"token operator\">&#8211;<\/span> offset<span class=\"token punctuation\">,<\/span><br \/>\n                         MSG_NOSIGNAL<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            offset <span class=\"token operator\">&#043;&#061;<\/span> <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n            <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EAGAIN <span class=\"token operator\">||<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EWOULDBLOCK<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            std<span class=\"token double-colon punctuation\">::<\/span>cerr<br \/>\n                <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;send buffer full; layer 03 has no EPOLLOUT queue\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;send&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> listen_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">socket<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n                           SOCK_STREAM <span class=\"token operator\">|<\/span> SOCK_CLOEXEC<span class=\"token punctuation\">,<\/span><br \/>\n                           <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>listen_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;socket&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">SetNonBlocking<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;fcntl(listen_fd)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">int<\/span> reuse <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">setsockopt<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n                   SOL_SOCKET<span class=\"token punctuation\">,<\/span><br \/>\n                   SO_REUSEADDR<span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token operator\">&amp;<\/span>reuse<span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>reuse<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;setsockopt&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    sockaddr_in server_addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_family <span class=\"token operator\">&#061;<\/span> AF_INET<span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">.<\/span>s_addr <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htonl<\/span><span class=\"token punctuation\">(<\/span>INADDR_ANY<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_port <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htons<\/span><span class=\"token punctuation\">(<\/span>kPort<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">bind<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n             <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n             <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;bind&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">listen<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span> kBacklog<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;listen&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">int<\/span> epoll_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">epoll_create1<\/span><span class=\"token punctuation\">(<\/span>EPOLL_CLOEXEC<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>epoll_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_create1&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    epoll_event listen_event<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    listen_event<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span> EPOLLIN <span class=\"token operator\">|<\/span> EPOLLET<span class=\"token punctuation\">;<\/span><br \/>\n    listen_event<span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd <span class=\"token operator\">&#061;<\/span> listen_fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  EPOLL_CTL_ADD<span class=\"token punctuation\">,<\/span><br \/>\n                  listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token operator\">&amp;<\/span>listen_event<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_ctl(ADD listen_fd)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>vector<span class=\"token operator\">&lt;<\/span>epoll_event<span class=\"token operator\">&gt;<\/span> <span class=\"token function\">ready_events<\/span><span class=\"token punctuation\">(<\/span>kMaxEvents<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>unordered_set<span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token operator\">&gt;<\/span> clients<span class=\"token punctuation\">;<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;epoll ET read-correct server listening on 0.0.0.0:&#034;<\/span><br \/>\n              <span class=\"token operator\">&lt;&lt;<\/span> kPort <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">int<\/span> ready_count <span class=\"token operator\">&#061;<\/span><br \/>\n            <span class=\"token function\">epoll_wait<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                       ready_events<span class=\"token punctuation\">.<\/span><span class=\"token function\">data<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                       <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>ready_events<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                       <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>ready_count <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_wait&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> ready_count<span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>i<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">int<\/span> current_fd <span class=\"token operator\">&#061;<\/span> ready_events<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd<span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">uint32_t<\/span> events <span class=\"token operator\">&#061;<\/span> ready_events<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>events<span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>current_fd <span class=\"token operator\">&#061;&#061;<\/span> listen_fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token comment\">\/\/ ET&#xff1a;\u5fc5\u987b\u4e00\u76f4 accept \u5230 EAGAIN\u3002<\/span><br \/>\n                <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    sockaddr_in client_addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    socklen_t client_len <span class=\"token operator\">&#061;<\/span><br \/>\n                        <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>client_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">int<\/span> client_fd <span class=\"token operator\">&#061;<\/span><br \/>\n                        <span class=\"token function\">accept<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n                               <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><br \/>\n                                   <span class=\"token operator\">&amp;<\/span>client_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                               <span class=\"token operator\">&amp;<\/span>client_len<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>client_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR <span class=\"token operator\">||<\/span><br \/>\n                            errno <span class=\"token operator\">&#061;&#061;<\/span> ECONNABORTED<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token punctuation\">}<\/span><\/p>\n<p>                        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EAGAIN <span class=\"token operator\">||<\/span><br \/>\n                            errno <span class=\"token operator\">&#061;&#061;<\/span> EWOULDBLOCK<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token punctuation\">}<\/span><\/p>\n<p>                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;accept&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">SetNonBlocking<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;fcntl(client_fd)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">AddClient<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span> client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_ctl(ADD client)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">char<\/span> ip<span class=\"token punctuation\">[<\/span>INET_ADDRSTRLEN<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token function\">inet_ntop<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n                              <span class=\"token operator\">&amp;<\/span>client_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">,<\/span><br \/>\n                              ip<span class=\"token punctuation\">,<\/span><br \/>\n                              <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>ip<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;connected: &#034;<\/span><br \/>\n                              <span class=\"token operator\">&lt;&lt;<\/span> ip <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;:&#039;<\/span><br \/>\n                              <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token function\">ntohs<\/span><span class=\"token punctuation\">(<\/span>client_addr<span class=\"token punctuation\">.<\/span>sin_port<span class=\"token punctuation\">)<\/span><br \/>\n                              <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;, fd&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> client_fd <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">insert<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><\/p>\n<p>                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">bool<\/span> close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>events <span class=\"token operator\">&amp;<\/span> EPOLLERR<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">0U<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">int<\/span> socket_error <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                socklen_t error_len <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>socket_error<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token function\">getsockopt<\/span><span class=\"token punctuation\">(<\/span>current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                           SOL_SOCKET<span class=\"token punctuation\">,<\/span><br \/>\n                           SO_ERROR<span class=\"token punctuation\">,<\/span><br \/>\n                           <span class=\"token operator\">&amp;<\/span>socket_error<span class=\"token punctuation\">,<\/span><br \/>\n                           <span class=\"token operator\">&amp;<\/span>error_len<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                std<span class=\"token double-colon punctuation\">::<\/span>cerr <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;socket error on fd&#061;&#034;<\/span><br \/>\n                          <span class=\"token operator\">&lt;&lt;<\/span> current_fd<br \/>\n                          <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;: errno&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> socket_error<br \/>\n                          <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>close_now <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n                <span class=\"token punctuation\">(<\/span>events <span class=\"token operator\">&amp;<\/span> EPOLLIN<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">0U<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token comment\">\/\/ ET \u6838\u5fc3&#xff1a;\u975e\u963b\u585e &#043; \u5faa\u73af recv&#xff0c;\u76f4\u5230 EAGAIN\u3002<\/span><br \/>\n                <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span>kBufferSize<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                                     buffer<span class=\"token punctuation\">,<\/span><br \/>\n                                     <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                                     <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;received &#034;<\/span><br \/>\n                                  <span class=\"token operator\">&lt;&lt;<\/span> n <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034; bytes from fd&#061;&#034;<\/span><br \/>\n                                  <span class=\"token operator\">&lt;&lt;<\/span> current_fd <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">SendImmediatelyOrFail<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                                current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                                buffer<span class=\"token punctuation\">,<\/span><br \/>\n                                <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                            close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token punctuation\">}<\/span><\/p>\n<p>                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EAGAIN <span class=\"token operator\">||<\/span><br \/>\n                        errno <span class=\"token operator\">&#061;&#061;<\/span> EWOULDBLOCK<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token comment\">\/\/ \u5f53\u524d\u63a5\u6536\u7f13\u51b2\u533a\u5df2\u7ecf\u6392\u7a7a\u3002<\/span><br \/>\n                        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;recv&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>events <span class=\"token operator\">&amp;<\/span><br \/>\n                 <span class=\"token punctuation\">(<\/span>EPOLLRDHUP <span class=\"token operator\">|<\/span> EPOLLHUP<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">0U<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>close_now<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token function\">CloseClient<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                            current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                            clients<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> client_fd <span class=\"token operator\">:<\/span> clients<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>11.2 \u5b8c\u6574\u5ba2\u6237\u7aef&#xff1a;03_epoll_et_correct_read\/client.cpp<\/h3>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;arpa\/inet.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/select.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/socket.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unistd.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cerrno&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstdio&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;iostream&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">namespace<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">bool<\/span> <span class=\"token function\">SendAll<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">char<\/span><span class=\"token operator\">*<\/span> data<span class=\"token punctuation\">,<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t size<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>size_t offset <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span>offset <span class=\"token operator\">&lt;<\/span> size<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">send<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span><br \/>\n                         data <span class=\"token operator\">&#043;<\/span> offset<span class=\"token punctuation\">,<\/span><br \/>\n                         size <span class=\"token operator\">&#8211;<\/span> offset<span class=\"token punctuation\">,<\/span><br \/>\n                         MSG_NOSIGNAL<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            offset <span class=\"token operator\">&#043;&#061;<\/span> <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;send&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> socket_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">socket<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span> SOCK_STREAM<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>socket_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;socket&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    sockaddr_in server_addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_family <span class=\"token operator\">&#061;<\/span> AF_INET<span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_port <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htons<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">8888<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">inet_pton<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token string\">&#034;127.0.0.1&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token operator\">&amp;<\/span>server_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span>cerr <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;invalid IPv4 address\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">connect<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span><br \/>\n                <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;connect&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;connected to 127.0.0.1:8888\\\\n&#034;<\/span><br \/>\n              <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;type text; Ctrl&#043;D stops sending but keeps receiving\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">bool<\/span> stdin_open <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        fd_set read_set<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>stdin_open<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>STDIN_FILENO<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">int<\/span> max_fd <span class=\"token operator\">&#061;<\/span> socket_fd <span class=\"token operator\">&gt;<\/span> STDIN_FILENO<br \/>\n                         <span class=\"token operator\">?<\/span> socket_fd<br \/>\n                         <span class=\"token operator\">:<\/span> STDIN_FILENO<span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">int<\/span> ready <span class=\"token operator\">&#061;<\/span><br \/>\n            <span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span>max_fd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>ready <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;select&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>stdin_open <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n            <span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span>STDIN_FILENO<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span><span class=\"token number\">4096<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span>STDIN_FILENO<span class=\"token punctuation\">,<\/span><br \/>\n                             buffer<span class=\"token punctuation\">,<\/span><br \/>\n                             <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">SendAll<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span><br \/>\n                             buffer<span class=\"token punctuation\">,<\/span><br \/>\n                             <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                stdin_open <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">shutdown<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span> SHUT_WR<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n                    errno <span class=\"token operator\">!&#061;<\/span> ENOTCONN<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;shutdown&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">!&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;read(stdin)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span><span class=\"token number\">4096<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span><br \/>\n                             buffer<span class=\"token punctuation\">,<\/span><br \/>\n                             <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                             <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span>cout<span class=\"token punctuation\">.<\/span><span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">,<\/span> n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span>cout<span class=\"token punctuation\">.<\/span><span class=\"token function\">flush<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;\\\\nserver closed connection\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">!&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;recv&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>11.3 \u672c\u5c42\u4fee\u590d\u4e86\u4ec0\u4e48<\/h3>\n<ul>\n<li>\u76d1\u542c fd \u5728 ET \u6a21\u5f0f\u4e0b\u6392\u7a7a\u8fde\u63a5\u961f\u5217&#xff1b;<\/li>\n<li>\u901a\u4fe1 fd \u5728 ET \u6a21\u5f0f\u4e0b\u6392\u7a7a\u63a5\u6536\u7f13\u51b2\u533a&#xff1b;<\/li>\n<li>\u6570\u636e\u4e0d\u4f1a\u56e0\u4e3a\u53ea\u8bfb\u4e00\u6b21\u800c\u957f\u671f\u6ede\u7559&#xff1b;<\/li>\n<li>\u4e8b\u4ef6\u5faa\u73af\u4e0d\u4f1a\u56e0\u4e3a\u963b\u585e recv() \u5361\u4f4f&#xff1b;<\/li>\n<li>EAGAIN \u6210\u4e3a\u201c\u672c\u8f6e\u5904\u7406\u5b8c\u6210\u201d\u7684\u8fb9\u754c\u3002<\/li>\n<\/ul>\n<h3>11.4 \u672c\u5c42\u4ecd\u7136\u6ca1\u6709\u89e3\u51b3\u5199\u8def\u5f84<\/h3>\n<p>\u5f53\u524d\u903b\u8f91\u4ecd\u7136\u8981\u6c42&#xff1a;<\/p>\n<p>\u6536\u5230\u4e00\u6279\u6570\u636e<br \/>\n    \u2502<br \/>\n    \u25bc<br \/>\n\u7acb\u5373 send<br \/>\n    \u2502<br \/>\n    \u251c\u2500 \u5168\u90e8\u53d1\u9001&#xff1a;\u6b63\u5e38<br \/>\n    \u2514\u2500 \u90e8\u5206\u53d1\u9001\/EAGAIN&#xff1a;\u5173\u95ed\u8fde\u63a5<\/p>\n<p>\u8fd9\u4e0d\u4f1a\u6084\u6084\u4e22\u6570\u636e&#xff0c;\u4f46\u4f1a\u9519\u8bef\u5730\u62d2\u7edd\u6162\u5ba2\u6237\u7aef\u3002<\/p>\n<p>\u8981\u6b63\u786e\u5904\u7406\u5b83&#xff0c;\u5fc5\u987b\u7406\u89e3 EPOLLOUT\u3002<\/p>\n<hr \/>\n<h2>\u7b2c\u4e03\u90e8\u5206&#xff1a;\u4e3a\u4ec0\u4e48\u4e0d\u80fd\u6c38\u4e45\u76d1\u542c EPOLLOUT<\/h2>\n<h3>\u5341\u4e8c\u3001\u5957\u63a5\u5b57\u201c\u53ef\u5199\u201d\u610f\u5473\u7740\u4ec0\u4e48<\/h3>\n<p>\u5bf9 TCP \u5957\u63a5\u5b57\u800c\u8a00&#xff0c;EPOLLOUT \u901a\u5e38\u8868\u793a&#xff1a;<\/p>\n<p>\u53d1\u9001\u7f13\u51b2\u533a\u5f53\u524d\u6709\u7a7a\u95f4&#xff0c;\u6267\u884c\u975e\u963b\u585e\u53d1\u9001\u53ef\u80fd\u53d6\u5f97\u8fdb\u5c55\u3002<\/p>\n<p>\u65b0\u5efa\u7acb\u7684 TCP \u8fde\u63a5\u5927\u591a\u6570\u65f6\u95f4\u90fd\u662f\u53ef\u5199\u7684\u3002<\/p>\n<p>\u5982\u679c\u65e0\u6761\u4ef6\u6c38\u4e45\u6ce8\u518c&#xff1a;<\/p>\n<p>EPOLLIN <span class=\"token operator\">|<\/span> EPOLLOUT<\/p>\n<p>\u4e8b\u4ef6\u5faa\u73af\u53ef\u80fd\u4e0d\u65ad\u5f97\u5230 EPOLLOUT&#xff1a;<\/p>\n<p>epoll_wait -&gt; fd \u53ef\u5199<br \/>\n\u6ca1\u6709\u6570\u636e\u9700\u8981\u53d1\u9001<br \/>\n\u518d\u6b21 epoll_wait -&gt; fd \u4ecd\u53ef\u5199<br \/>\n\u6ca1\u6709\u6570\u636e\u9700\u8981\u53d1\u9001<br \/>\n\u2026\u2026<\/p>\n<p>\u8fd9\u4f1a\u5f62\u6210\u65e0\u610f\u4e49\u7684\u9ad8\u9891\u5524\u9192\u3002<\/p>\n<p>\u56e0\u6b64\u5e38\u89c1\u7b56\u7565\u662f&#xff1a;<\/p>\n<p>\u6ca1\u6709\u5f85\u53d1\u9001\u6570\u636e&#xff1a;<br \/>\n    \u53ea\u76d1\u542c EPOLLIN<\/p>\n<p>\u51fa\u73b0\u5f85\u53d1\u9001\u6570\u636e&#xff1a;<br \/>\n    \u5148\u4e3b\u52a8 send<\/p>\n<p>\u5168\u90e8\u53d1\u9001\u5b8c\u6210&#xff1a;<br \/>\n    \u4e0d\u76d1\u542c EPOLLOUT<\/p>\n<p>send \u8fd4\u56de EAGAIN \u6216\u53ea\u5b8c\u6210\u4e00\u90e8\u5206&#xff1a;<br \/>\n    \u4fdd\u5b58\u5269\u4f59\u6570\u636e<br \/>\n    \u6ce8\u518c EPOLLOUT<\/p>\n<p>\u540e\u7eed EPOLLOUT \u5230\u6765&#xff1a;<br \/>\n    \u7ee7\u7eed\u53d1\u9001<\/p>\n<h3>\u5341\u4e09\u3001\u4e3a\u4ec0\u4e48\u6bcf\u4e2a\u8fde\u63a5\u90fd\u9700\u8981\u72ec\u7acb\u53d1\u9001\u72b6\u6001<\/h3>\n<p>TCP \u53d1\u9001\u662f\u6bcf\u8fde\u63a5\u72ec\u7acb\u7684&#xff0c;\u56e0\u6b64\u9700\u8981&#xff1a;<\/p>\n<p><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">ClientState<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string output<span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>size_t sent_offset<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5047\u8bbe&#xff1a;<\/p>\n<p>output &#061; &#034;ABCDEFGHIJ&#034;<br \/>\nsent_offset &#061; 4<\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>\u5df2\u7ecf\u53d1\u9001&#xff1a;ABCD<br \/>\n\u7b49\u5f85\u53d1\u9001&#xff1a;EFGHIJ<\/p>\n<p>\u4e0b\u4e00\u6b21\u53d1\u9001\u5730\u5740\u4e3a&#xff1a;<\/p>\n<p>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">data<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#043;<\/span> sent_offset<\/p>\n<p>\u5269\u4f59\u957f\u5ea6\u4e3a&#xff1a;<\/p>\n<p>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#8211;<\/span> sent_offset<\/p>\n<hr \/>\n<h2>\u7b2c\u516b\u90e8\u5206&#xff1a;\u7b2c 4 \u5c42\u2014\u2014ET &#043; \u53d1\u9001\u961f\u5217 &#043; EPOLLOUT<\/h2>\n<h3>\u5341\u56db\u3001\u672c\u5c42\u65b0\u589e\u7684\u72b6\u6001\u673a<\/h3>\n<p>                    \u6536\u5230\u5ba2\u6237\u7aef\u6570\u636e<br \/>\n                           \u2502<br \/>\n                           \u25bc<br \/>\n                     \u8ffd\u52a0 output<br \/>\n                           \u2502<br \/>\n                           \u25bc<br \/>\n                    \u4e3b\u52a8\u5c1d\u8bd5 send<br \/>\n                      \u2502          \u2502<br \/>\n                      \u2502          \u2514\u2500 EAGAIN \/ \u90e8\u5206\u53d1\u9001<br \/>\n                      \u2502                    \u2502<br \/>\n                      \u25bc                    \u25bc<br \/>\n                 \u5168\u90e8\u53d1\u5b8c            \u4fdd\u7559 sent_offset<br \/>\n                      \u2502                    \u2502<br \/>\n             \u79fb\u9664 EPOLLOUT          \u6ce8\u518c EPOLLOUT<br \/>\n                                           \u2502<br \/>\n                                           \u25bc<br \/>\n                                    \u4e0b\u6b21\u53ef\u5199\u65f6\u7ee7\u7eed<\/p>\n<h3>14.1 \u5b8c\u6574\u670d\u52a1\u7aef&#xff1a;04_epoll_et_write_queue\/server.cpp<\/h3>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;arpa\/inet.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;fcntl.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/epoll.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/socket.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unistd.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cerrno&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstdio&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;iostream&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;string&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unordered_map&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;vector&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">namespace<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> <span class=\"token keyword\">uint16_t<\/span> kPort <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">8888<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> <span class=\"token keyword\">int<\/span> kBacklog <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">128<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> <span class=\"token keyword\">int<\/span> kMaxEvents <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">64<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t kBufferSize <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">4096<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">ClientState<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string peer<span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string output<span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>size_t sent_offset <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">bool<\/span> peer_closed_write <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">bool<\/span> <span class=\"token function\">SetNonBlocking<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> old_flags <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> F_GETFL<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>old_flags <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span><br \/>\n                 F_SETFL<span class=\"token punctuation\">,<\/span><br \/>\n                 old_flags <span class=\"token operator\">|<\/span> O_NONBLOCK<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>std<span class=\"token double-colon punctuation\">::<\/span>size_t <span class=\"token function\">PendingBytes<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> ClientState<span class=\"token operator\">&amp;<\/span> client<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#8211;<\/span> client<span class=\"token punctuation\">.<\/span>sent_offset<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">void<\/span> <span class=\"token function\">CompactOutput<\/span><span class=\"token punctuation\">(<\/span>ClientState<span class=\"token operator\">&amp;<\/span> client<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">.<\/span>sent_offset <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">return<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">.<\/span>sent_offset <span class=\"token operator\">&#061;&#061;<\/span> client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">clear<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        client<span class=\"token punctuation\">.<\/span>sent_offset <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">.<\/span>sent_offset <span class=\"token operator\">&gt;&#061;<\/span> <span class=\"token number\">4096<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n        client<span class=\"token punctuation\">.<\/span>sent_offset <span class=\"token operator\">*<\/span> <span class=\"token number\">2<\/span> <span class=\"token operator\">&gt;&#061;<\/span> client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">erase<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">0<\/span><span class=\"token punctuation\">,<\/span> client<span class=\"token punctuation\">.<\/span>sent_offset<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        client<span class=\"token punctuation\">.<\/span>sent_offset <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">uint32_t<\/span> <span class=\"token function\">BuildClientEvents<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> ClientState<span class=\"token operator\">&amp;<\/span> client<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">uint32_t<\/span> events <span class=\"token operator\">&#061;<\/span> EPOLLET <span class=\"token operator\">|<\/span> EPOLLRDHUP<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>client<span class=\"token punctuation\">.<\/span>peer_closed_write<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        events <span class=\"token operator\">|&#061;<\/span> EPOLLIN<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">PendingBytes<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        events <span class=\"token operator\">|&#061;<\/span> EPOLLOUT<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> events<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">bool<\/span> <span class=\"token function\">ModifyClientEvents<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                        <span class=\"token keyword\">int<\/span> client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                        <span class=\"token keyword\">const<\/span> ClientState<span class=\"token operator\">&amp;<\/span> client<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    epoll_event event<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    event<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">BuildClientEvents<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    event<span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd <span class=\"token operator\">&#061;<\/span> client_fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  EPOLL_CTL_MOD<span class=\"token punctuation\">,<\/span><br \/>\n                  client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token operator\">&amp;<\/span>event<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_ctl(MOD client)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">void<\/span> <span class=\"token function\">CloseClient<\/span><span class=\"token punctuation\">(<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> client_fd<span class=\"token punctuation\">,<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>unordered_map<span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token punctuation\">,<\/span> ClientState<span class=\"token operator\">&gt;<\/span><span class=\"token operator\">&amp;<\/span> clients<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  EPOLL_CTL_DEL<span class=\"token punctuation\">,<\/span><br \/>\n                  client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n        errno <span class=\"token operator\">!&#061;<\/span> ENOENT <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n        errno <span class=\"token operator\">!&#061;<\/span> EBADF<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_ctl(DEL)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">erase<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;closed fd&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> client_fd <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">bool<\/span> <span class=\"token function\">FlushOutput<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                 ClientState<span class=\"token operator\">&amp;<\/span> client<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">.<\/span>sent_offset <span class=\"token operator\">&lt;<\/span> client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">char<\/span><span class=\"token operator\">*<\/span> data <span class=\"token operator\">&#061;<\/span><br \/>\n            client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">data<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#043;<\/span> client<span class=\"token punctuation\">.<\/span>sent_offset<span class=\"token punctuation\">;<\/span><\/p>\n<p>        std<span class=\"token double-colon punctuation\">::<\/span>size_t remain <span class=\"token operator\">&#061;<\/span><br \/>\n            client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#8211;<\/span> client<span class=\"token punctuation\">.<\/span>sent_offset<span class=\"token punctuation\">;<\/span><\/p>\n<p>        ssize_t n <span class=\"token operator\">&#061;<\/span><br \/>\n            <span class=\"token function\">send<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                 data<span class=\"token punctuation\">,<\/span><br \/>\n                 remain<span class=\"token punctuation\">,<\/span><br \/>\n                 MSG_NOSIGNAL<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            client<span class=\"token punctuation\">.<\/span>sent_offset <span class=\"token operator\">&#043;&#061;<\/span><br \/>\n                <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n            <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EAGAIN <span class=\"token operator\">||<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EWOULDBLOCK<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token comment\">\/\/ \u53d1\u9001\u7f13\u51b2\u533a\u6682\u65f6\u5df2\u6ee1&#xff0c;\u4fdd\u7559\u672a\u53d1\u9001\u6570\u636e&#xff0c;<\/span><br \/>\n            <span class=\"token comment\">\/\/ \u7b49\u5f85\u4e0b\u4e00\u6b21 EPOLLOUT\u3002<\/span><br \/>\n            <span class=\"token function\">CompactOutput<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;send&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">CompactOutput<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> listen_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">socket<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n                           SOCK_STREAM <span class=\"token operator\">|<\/span> SOCK_CLOEXEC<span class=\"token punctuation\">,<\/span><br \/>\n                           <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>listen_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;socket&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">SetNonBlocking<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;fcntl(listen_fd)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">int<\/span> reuse <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">setsockopt<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n                   SOL_SOCKET<span class=\"token punctuation\">,<\/span><br \/>\n                   SO_REUSEADDR<span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token operator\">&amp;<\/span>reuse<span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>reuse<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;setsockopt&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    sockaddr_in server_addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_family <span class=\"token operator\">&#061;<\/span> AF_INET<span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">.<\/span>s_addr <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htonl<\/span><span class=\"token punctuation\">(<\/span>INADDR_ANY<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_port <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htons<\/span><span class=\"token punctuation\">(<\/span>kPort<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">bind<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n             <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n             <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;bind&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">listen<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span> kBacklog<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;listen&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">int<\/span> epoll_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">epoll_create1<\/span><span class=\"token punctuation\">(<\/span>EPOLL_CLOEXEC<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>epoll_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_create1&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    epoll_event listen_event<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    listen_event<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span> EPOLLIN <span class=\"token operator\">|<\/span> EPOLLET<span class=\"token punctuation\">;<\/span><br \/>\n    listen_event<span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd <span class=\"token operator\">&#061;<\/span> listen_fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  EPOLL_CTL_ADD<span class=\"token punctuation\">,<\/span><br \/>\n                  listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token operator\">&amp;<\/span>listen_event<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_ctl(ADD listen_fd)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>vector<span class=\"token operator\">&lt;<\/span>epoll_event<span class=\"token operator\">&gt;<\/span> <span class=\"token function\">ready_events<\/span><span class=\"token punctuation\">(<\/span>kMaxEvents<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>unordered_map<span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token punctuation\">,<\/span> ClientState<span class=\"token operator\">&gt;<\/span> clients<span class=\"token punctuation\">;<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;epoll ET output-queue server listening on 0.0.0.0:&#034;<\/span><br \/>\n              <span class=\"token operator\">&lt;&lt;<\/span> kPort <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">int<\/span> ready_count <span class=\"token operator\">&#061;<\/span><br \/>\n            <span class=\"token function\">epoll_wait<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                       ready_events<span class=\"token punctuation\">.<\/span><span class=\"token function\">data<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                       <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>ready_events<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                       <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>ready_count <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_wait&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> ready_count<span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>i<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">int<\/span> current_fd <span class=\"token operator\">&#061;<\/span> ready_events<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd<span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">uint32_t<\/span> events <span class=\"token operator\">&#061;<\/span> ready_events<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>events<span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>current_fd <span class=\"token operator\">&#061;&#061;<\/span> listen_fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    sockaddr_in client_addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    socklen_t client_len <span class=\"token operator\">&#061;<\/span><br \/>\n                        <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>client_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">int<\/span> client_fd <span class=\"token operator\">&#061;<\/span><br \/>\n                        <span class=\"token function\">accept<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n                               <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><br \/>\n                                   <span class=\"token operator\">&amp;<\/span>client_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                               <span class=\"token operator\">&amp;<\/span>client_len<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>client_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR <span class=\"token operator\">||<\/span><br \/>\n                            errno <span class=\"token operator\">&#061;&#061;<\/span> ECONNABORTED<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token punctuation\">}<\/span><\/p>\n<p>                        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EAGAIN <span class=\"token operator\">||<\/span><br \/>\n                            errno <span class=\"token operator\">&#061;&#061;<\/span> EWOULDBLOCK<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token punctuation\">}<\/span><\/p>\n<p>                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;accept&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">SetNonBlocking<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;fcntl(client_fd)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">char<\/span> ip<span class=\"token punctuation\">[<\/span>INET_ADDRSTRLEN<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token function\">inet_ntop<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n                              <span class=\"token operator\">&amp;<\/span>client_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">,<\/span><br \/>\n                              ip<span class=\"token punctuation\">,<\/span><br \/>\n                              <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>ip<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    ClientState client<span class=\"token punctuation\">;<\/span><br \/>\n                    client<span class=\"token punctuation\">.<\/span>peer <span class=\"token operator\">&#061;<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">string<\/span><span class=\"token punctuation\">(<\/span>ip<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#043;<\/span> <span class=\"token string\">&#034;:&#034;<\/span> <span class=\"token operator\">&#043;<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">to_string<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                            <span class=\"token function\">ntohs<\/span><span class=\"token punctuation\">(<\/span>client_addr<span class=\"token punctuation\">.<\/span>sin_port<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    epoll_event client_event<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    client_event<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span><br \/>\n                        EPOLLIN <span class=\"token operator\">|<\/span> EPOLLRDHUP <span class=\"token operator\">|<\/span> EPOLLET<span class=\"token punctuation\">;<\/span><br \/>\n                    client_event<span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd <span class=\"token operator\">&#061;<\/span> client_fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                                  EPOLL_CTL_ADD<span class=\"token punctuation\">,<\/span><br \/>\n                                  client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                                  <span class=\"token operator\">&amp;<\/span>client_event<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                            <span class=\"token string\">&#034;epoll_ctl(ADD client)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;connected: &#034;<\/span><br \/>\n                              <span class=\"token operator\">&lt;&lt;<\/span> client<span class=\"token punctuation\">.<\/span>peer<br \/>\n                              <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;, fd&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> client_fd <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">emplace<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                                    std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">move<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><\/p>\n<p>                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">auto<\/span> it <span class=\"token operator\">&#061;<\/span> clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">find<\/span><span class=\"token punctuation\">(<\/span>current_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>it <span class=\"token operator\">&#061;&#061;<\/span> clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">end<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            ClientState<span class=\"token operator\">&amp;<\/span> client <span class=\"token operator\">&#061;<\/span> it<span class=\"token operator\">-&gt;<\/span>second<span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">bool<\/span> close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>events <span class=\"token operator\">&amp;<\/span> EPOLLERR<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">0U<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">int<\/span> socket_error <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                socklen_t error_len <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>socket_error<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token function\">getsockopt<\/span><span class=\"token punctuation\">(<\/span>current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                           SOL_SOCKET<span class=\"token punctuation\">,<\/span><br \/>\n                           SO_ERROR<span class=\"token punctuation\">,<\/span><br \/>\n                           <span class=\"token operator\">&amp;<\/span>socket_error<span class=\"token punctuation\">,<\/span><br \/>\n                           <span class=\"token operator\">&amp;<\/span>error_len<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                std<span class=\"token double-colon punctuation\">::<\/span>cerr <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;socket error on fd&#061;&#034;<\/span><br \/>\n                          <span class=\"token operator\">&lt;&lt;<\/span> current_fd<br \/>\n                          <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;: errno&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> socket_error<br \/>\n                          <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>close_now <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n                <span class=\"token punctuation\">(<\/span>events <span class=\"token operator\">&amp;<\/span><br \/>\n                 <span class=\"token punctuation\">(<\/span>EPOLLIN <span class=\"token operator\">|<\/span> EPOLLRDHUP <span class=\"token operator\">|<\/span> EPOLLHUP<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">0U<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span>kBufferSize<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                                     buffer<span class=\"token punctuation\">,<\/span><br \/>\n                                     <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                                     <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token function\">CompactOutput<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">append<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                            buffer<span class=\"token punctuation\">,<\/span><br \/>\n                            <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                        std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;queued &#034;<\/span><br \/>\n                                  <span class=\"token operator\">&lt;&lt;<\/span> n <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034; echo bytes for fd&#061;&#034;<\/span><br \/>\n                                  <span class=\"token operator\">&lt;&lt;<\/span> current_fd <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        client<span class=\"token punctuation\">.<\/span>peer_closed_write <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EAGAIN <span class=\"token operator\">||<\/span><br \/>\n                        errno <span class=\"token operator\">&#061;&#061;<\/span> EWOULDBLOCK<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;recv&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token comment\">\/\/ EPOLLRDHUP\/EPOLLHUP \u53ea\u662f\u201c\u5bf9\u7aef\u5173\u95ed\u65b9\u5411\u53d1\u751f\u53d8\u5316\u201d\u7684\u63d0\u793a\u3002<\/span><br \/>\n            <span class=\"token comment\">\/\/ \u4ecd\u8981\u901a\u8fc7 recv() \u8fd4\u56de 0 \u786e\u8ba4\u63a5\u6536\u65b9\u5411\u5df2\u7ecf\u5230\u8fbe EOF&#xff0c;<\/span><br \/>\n            <span class=\"token comment\">\/\/ \u56e0\u4e3a FIN \u4e4b\u524d\u53ef\u80fd\u8fd8\u6709\u5c1a\u672a\u8bfb\u53d6\u7684\u6570\u636e\u3002<\/span><\/p>\n<p>            <span class=\"token comment\">\/\/ \u65e0\u8bba\u672c\u8f6e\u662f\u5426\u5e26 EPOLLOUT&#xff0c;\u53ea\u8981\u5b58\u5728\u5f85\u53d1\u9001\u6570\u636e&#xff0c;<\/span><br \/>\n            <span class=\"token comment\">\/\/ \u90fd\u5148\u4e3b\u52a8\u5c1d\u8bd5\u4e00\u6b21\u53d1\u9001&#xff1b;\u5199\u4e0d\u52a8\u518d\u8ba2\u9605 EPOLLOUT\u3002<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>close_now <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n                <span class=\"token function\">PendingBytes<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">FlushOutput<\/span><span class=\"token punctuation\">(<\/span>current_fd<span class=\"token punctuation\">,<\/span> client<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>close_now <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n                client<span class=\"token punctuation\">.<\/span>peer_closed_write <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n                <span class=\"token function\">PendingBytes<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>close_now<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token function\">CloseClient<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                            current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                            clients<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">ModifyClientEvents<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                                    current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                                    client<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token function\">CloseClient<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                            current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                            clients<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> <span class=\"token keyword\">auto<\/span><span class=\"token operator\">&amp;<\/span> <span class=\"token punctuation\">[<\/span>client_fd<span class=\"token punctuation\">,<\/span> client<span class=\"token punctuation\">]<\/span> <span class=\"token operator\">:<\/span> clients<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">void<\/span><span class=\"token punctuation\">)<\/span>client<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>14.2 \u5b8c\u6574\u5ba2\u6237\u7aef&#xff1a;04_epoll_et_write_queue\/client.cpp<\/h3>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;arpa\/inet.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/select.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/socket.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unistd.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cerrno&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstdio&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;iostream&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">namespace<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">bool<\/span> <span class=\"token function\">SendAll<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">char<\/span><span class=\"token operator\">*<\/span> data<span class=\"token punctuation\">,<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t size<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>size_t offset <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span>offset <span class=\"token operator\">&lt;<\/span> size<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">send<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span><br \/>\n                         data <span class=\"token operator\">&#043;<\/span> offset<span class=\"token punctuation\">,<\/span><br \/>\n                         size <span class=\"token operator\">&#8211;<\/span> offset<span class=\"token punctuation\">,<\/span><br \/>\n                         MSG_NOSIGNAL<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            offset <span class=\"token operator\">&#043;&#061;<\/span> <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;send&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> socket_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">socket<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span> SOCK_STREAM<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>socket_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;socket&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    sockaddr_in server_addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_family <span class=\"token operator\">&#061;<\/span> AF_INET<span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_port <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htons<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">8888<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">inet_pton<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token string\">&#034;127.0.0.1&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token operator\">&amp;<\/span>server_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span>cerr <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;invalid IPv4 address\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">connect<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span><br \/>\n                <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;connect&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;connected to 127.0.0.1:8888\\\\n&#034;<\/span><br \/>\n              <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;type text; Ctrl&#043;D stops sending but keeps receiving\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">bool<\/span> stdin_open <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        fd_set read_set<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>stdin_open<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>STDIN_FILENO<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">int<\/span> max_fd <span class=\"token operator\">&#061;<\/span> socket_fd <span class=\"token operator\">&gt;<\/span> STDIN_FILENO<br \/>\n                         <span class=\"token operator\">?<\/span> socket_fd<br \/>\n                         <span class=\"token operator\">:<\/span> STDIN_FILENO<span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">int<\/span> ready <span class=\"token operator\">&#061;<\/span><br \/>\n            <span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span>max_fd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>ready <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;select&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>stdin_open <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n            <span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span>STDIN_FILENO<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span><span class=\"token number\">4096<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span>STDIN_FILENO<span class=\"token punctuation\">,<\/span><br \/>\n                             buffer<span class=\"token punctuation\">,<\/span><br \/>\n                             <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">SendAll<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span><br \/>\n                             buffer<span class=\"token punctuation\">,<\/span><br \/>\n                             <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                stdin_open <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">shutdown<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span> SHUT_WR<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n                    errno <span class=\"token operator\">!&#061;<\/span> ENOTCONN<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;shutdown&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">!&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;read(stdin)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span><span class=\"token number\">4096<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span><br \/>\n                             buffer<span class=\"token punctuation\">,<\/span><br \/>\n                             <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                             <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span>cout<span class=\"token punctuation\">.<\/span><span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">,<\/span> n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span>cout<span class=\"token punctuation\">.<\/span><span class=\"token function\">flush<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;\\\\nserver closed connection\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">!&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;recv&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>14.3 BuildClientEvents() \u7684\u610f\u4e49<\/h3>\n<p>\u4e8b\u4ef6\u63a9\u7801\u4e0d\u80fd\u518d\u5199\u6b7b&#xff1a;<\/p>\n<p><span class=\"token keyword\">uint32_t<\/span> <span class=\"token function\">BuildClientEvents<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> ClientState<span class=\"token operator\">&amp;<\/span> client<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">uint32_t<\/span> events <span class=\"token operator\">&#061;<\/span> EPOLLET <span class=\"token operator\">|<\/span> EPOLLRDHUP<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>client<span class=\"token punctuation\">.<\/span>peer_closed_write<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        events <span class=\"token operator\">|&#061;<\/span> EPOLLIN<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">PendingBytes<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        events <span class=\"token operator\">|&#061;<\/span> EPOLLOUT<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> events<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u5b83\u628a\u8fde\u63a5\u72b6\u6001\u6620\u5c04\u6210\u5185\u6838\u5174\u8da3\u96c6\u5408&#xff1a;<\/p>\n<p>\u8fde\u63a5\u4ecd\u53ef\u63a5\u6536\u6570\u636e      -&gt; EPOLLIN<br \/>\n\u5b58\u5728\u5f85\u53d1\u9001\u6570\u636e        -&gt; EPOLLOUT<br \/>\n\u4f7f\u7528\u8fb9\u7f18\u89e6\u53d1          -&gt; EPOLLET<br \/>\n\u5173\u6ce8\u5bf9\u7aef\u534a\u5173\u95ed        -&gt; EPOLLRDHUP<\/p>\n<h3>14.4 \u4e3a\u4ec0\u4e48\u6536\u5230\u6570\u636e\u540e\u5148\u4e3b\u52a8\u53d1\u9001<\/h3>\n<p>\u6536\u5230\u6570\u636e\u5e76\u52a0\u5165\u53d1\u9001\u961f\u5217\u540e&#xff0c;\u4e0d\u5fc5\u7b49\u4e0b\u4e00\u6b21 EPOLLOUT \u624d\u7b2c\u4e00\u6b21\u5c1d\u8bd5\u53d1\u9001\u3002<\/p>\n<p>\u5957\u63a5\u5b57\u6b64\u65f6\u5f88\u53ef\u80fd\u5df2\u7ecf\u53ef\u5199&#xff1a;<\/p>\n<p>client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">append<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">,<\/span> n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">FlushOutput<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> client<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u53ea\u6709\u786e\u5b9e\u5199\u4e0d\u52a8\u65f6&#xff0c;\u624d\u628a EPOLLOUT \u52a0\u5165\u4e8b\u4ef6\u63a9\u7801\u3002<\/p>\n<h3>14.5 EPOLLRDHUP \u4e0d\u80fd\u76f4\u63a5\u7b49\u540c\u4e8e\u201c\u6240\u6709\u6570\u636e\u5df2\u7ecf\u8bfb\u5b8c\u201d<\/h3>\n<p>\u8fd9\u662f\u4e00\u4e2a\u975e\u5e38\u5bb9\u6613\u5199\u9519\u7684\u7ec6\u8282\u3002<\/p>\n<p>TCP \u6570\u636e\u548c FIN \u7684\u987a\u5e8f\u53ef\u80fd\u662f&#xff1a;<\/p>\n<p>\u4e1a\u52a1\u6570\u636e 1<br \/>\n\u4e1a\u52a1\u6570\u636e 2<br \/>\nFIN<\/p>\n<p>\u5f53 epoll \u62a5\u544a EPOLLRDHUP \u65f6&#xff0c;\u63a5\u6536\u7f13\u51b2\u533a\u4e2d\u4ecd\u53ef\u80fd\u5b58\u5728 FIN \u4e4b\u524d\u5230\u8fbe\u4f46\u5c1a\u672a\u8bfb\u53d6\u7684\u4e1a\u52a1\u6570\u636e\u3002<\/p>\n<p>\u56e0\u6b64\u6b63\u786e\u505a\u6cd5\u662f&#xff1a;<\/p>\n<p>EPOLLRDHUP \/ EPOLLHUP<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\n\u7ee7\u7eed\u6267\u884c\u975e\u963b\u585e recv()<br \/>\n        \u2502<br \/>\n        \u251c\u2500 n &gt; 0&#xff1a;\u7ee7\u7eed\u5904\u7406\u9057\u7559\u6570\u636e<br \/>\n        \u2514\u2500 n &#061;&#061; 0&#xff1a;\u624d\u786e\u8ba4\u63a5\u6536\u65b9\u5411 EOF<\/p>\n<p>EPOLLRDHUP \u662f\u5173\u95ed\u65b9\u5411\u53d8\u5316\u7684\u63d0\u793a&#xff0c;recv() &#061;&#061; 0 \u624d\u662f\u63a5\u6536\u65b9\u5411\u5230\u8fbe EOF \u7684\u786e\u8ba4\u3002<\/p>\n<h3>14.6 \u672c\u5c42\u4fee\u590d\u4e86\u4ec0\u4e48<\/h3>\n<ul>\n<li>\u6b63\u786e\u5904\u7406\u90e8\u5206\u53d1\u9001&#xff1b;<\/li>\n<li>\u6b63\u786e\u5904\u7406 send() \u8fd4\u56de EAGAIN&#xff1b;<\/li>\n<li>\u4e0d\u518d\u56e0\u6162\u5ba2\u6237\u7aef\u6682\u65f6\u5199\u4e0d\u52a8\u800c\u7acb\u5373\u65ad\u5f00&#xff1b;<\/li>\n<li>\u4ec5\u5728\u786e\u5b9e\u5b58\u5728\u5f85\u53d1\u9001\u6570\u636e\u65f6\u76d1\u542c EPOLLOUT&#xff1b;<\/li>\n<li>\u652f\u6301\u5ba2\u6237\u7aef\u6267\u884c shutdown(SHUT_WR) \u540e\u7ee7\u7eed\u63a5\u6536\u56de\u663e&#xff1b;<\/li>\n<li>\u53d1\u9001\u5b8c\u6700\u540e\u7684\u6570\u636e\u540e\u518d\u5173\u95ed\u8fde\u63a5&#xff1b;<\/li>\n<li>\u4f7f\u7528 MSG_NOSIGNAL \u9632\u6b62 SIGPIPE \u7ed3\u675f\u8fdb\u7a0b\u3002<\/li>\n<\/ul>\n<h3>14.7 \u672c\u5c42\u7684\u65b0\u98ce\u9669&#xff1a;\u5185\u5b58\u65e0\u9650\u589e\u957f<\/h3>\n<p>\u5982\u679c\u5ba2\u6237\u7aef\u6301\u7eed\u53d1\u9001&#xff0c;\u4f46\u4ece\u4e0d\u8bfb\u53d6\u670d\u52a1\u7aef\u56de\u663e&#xff1a;<\/p>\n<p>\u5ba2\u6237\u7aef\u4e0d\u65ad\u53d1\u9001<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\n\u670d\u52a1\u7aef\u4e0d\u65ad append \u5230 output<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\n\u5ba2\u6237\u7aef\u4e0d\u63a5\u6536<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\n\u5185\u6838\u53d1\u9001\u7f13\u51b2\u533a\u6ee1<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\noutput \u8d8a\u79ef\u8d8a\u591a<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\n\u8fdb\u7a0b\u5185\u5b58\u8017\u5c3d<\/p>\n<p>\u56e0\u6b64\u201c\u6709\u53d1\u9001\u961f\u5217\u201d\u8fd8\u4e0d\u591f&#xff0c;\u5fc5\u987b\u589e\u52a0\u80cc\u538b\u3002<\/p>\n<hr \/>\n<h2>\u7b2c\u4e5d\u90e8\u5206&#xff1a;\u80cc\u538b\u662f\u4ec0\u4e48<\/h2>\n<h3>\u5341\u4e94\u3001\u80cc\u538b\u7684\u6838\u5fc3\u542b\u4e49<\/h3>\n<p>\u80cc\u538b\u4e0d\u662f\u4e00\u4e2a\u7279\u5b9a\u7cfb\u7edf\u8c03\u7528&#xff0c;\u800c\u662f\u4e00\u79cd\u6d41\u91cf\u63a7\u5236\u7b56\u7565&#xff1a;<\/p>\n<p>\u5f53\u4e0b\u6e38\u5904\u7406\u901f\u5ea6\u8ddf\u4e0d\u4e0a\u4e0a\u6e38\u751f\u4ea7\u901f\u5ea6\u65f6&#xff0c;\u9650\u5236\u6216\u6682\u505c\u4e0a\u6e38\u7ee7\u7eed\u4ea7\u751f\u6570\u636e\u3002<\/p>\n<p>\u5728 Echo \u670d\u52a1\u5668\u4e2d&#xff1a;<\/p>\n<p>\u5ba2\u6237\u7aef\u53d1\u9001\u901f\u5ea6 &#061; \u4e0a\u6e38\u751f\u4ea7\u901f\u5ea6<br \/>\n\u5ba2\u6237\u7aef\u8bfb\u53d6\u56de\u663e\u901f\u5ea6 &#061; \u4e0b\u6e38\u6d88\u8d39\u901f\u5ea6<\/p>\n<p>\u6162\u5ba2\u6237\u7aef\u9020\u6210\u7684\u95ee\u9898\u662f&#xff1a;<\/p>\n<p>recv \u5f88\u5feb<br \/>\nsend \u5f88\u6162<br \/>\noutput \u6301\u7eed\u589e\u957f<\/p>\n<h3>\u5341\u516d\u3001\u9ad8\u4f4e\u6c34\u4f4d<\/h3>\n<p>\u4f7f\u7528\u4e24\u4e2a\u9608\u503c\u800c\u4e0d\u662f\u4e00\u4e2a\u9608\u503c&#xff0c;\u53ef\u4ee5\u907f\u514d\u4e8b\u4ef6\u63a9\u7801\u9891\u7e41\u6296\u52a8&#xff1a;<\/p>\n<p>output &lt; 128 KiB<br \/>\n    \u6b63\u5e38\u8bfb\u53d6<\/p>\n<p>output &gt;&#061; 256 KiB<br \/>\n    \u6682\u505c EPOLLIN<\/p>\n<p>\u6682\u505c\u540e output \u9010\u6e10\u53d1\u9001<\/p>\n<p>output &lt;&#061; 128 KiB<br \/>\n    \u6062\u590d EPOLLIN<\/p>\n<p>ASCII \u56fe&#xff1a;<\/p>\n<p>\u5f85\u53d1\u9001\u5b57\u8282<br \/>\n   \u25b2<br \/>\n1M \u2502                     \u786c\u4e0a\u9650&#xff1a;\u8d85\u8fc7\u5219\u5173\u95ed<br \/>\n   \u2502<br \/>\n256K\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500 \u9ad8\u6c34\u4f4d&#xff1a;\u6682\u505c\u8bfb\u53d6<br \/>\n   \u2502              \u2572<br \/>\n   \u2502               \u2572 \u53d1\u9001\u961f\u5217\u9010\u6b65\u4e0b\u964d<br \/>\n128K\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2572\u2500\u2500 \u4f4e\u6c34\u4f4d&#xff1a;\u6062\u590d\u8bfb\u53d6<br \/>\n   \u2502<br \/>\n 0 \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2192 \u65f6\u95f4<\/p>\n<h3>\u5341\u4e03\u3001\u4e3a\u4ec0\u4e48\u8fd8\u9700\u8981\u786c\u4e0a\u9650<\/h3>\n<p>\u9ad8\u6c34\u4f4d\u53ea\u662f\u6682\u505c\u8bfb\u53d6&#xff0c;\u4f46\u4ee5\u4e0b\u60c5\u51b5\u4ecd\u53ef\u80fd\u8ba9\u53d1\u9001\u961f\u5217\u7a81\u7834\u9884\u671f&#xff1a;<\/p>\n<ul>\n<li>\u5355\u6b21\u8bfb\u53d6\u7684\u6570\u636e\u672c\u8eab\u5f88\u5927&#xff1b;<\/li>\n<li>\u4e1a\u52a1\u5c42\u4e00\u6b21\u751f\u6210\u5927\u91cf\u54cd\u5e94&#xff1b;<\/li>\n<li>\u591a\u4e2a\u5904\u7406\u6b65\u9aa4\u5728\u6682\u505c\u751f\u6548\u524d\u5df2\u7ecf\u8ffd\u52a0\u6570\u636e&#xff1b;<\/li>\n<li>\u4ee3\u7801\u7f3a\u9677\u5bfc\u81f4\u7ee7\u7eed\u5165\u961f\u3002<\/li>\n<\/ul>\n<p>\u56e0\u6b64\u8fd8\u5e94\u8bbe\u7f6e\u786c\u4e0a\u9650&#xff1a;<\/p>\n<p><span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>pending <span class=\"token operator\">&#043;<\/span> incoming <span class=\"token operator\">&gt;<\/span> kOutputHardLimit<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token function\">close_connection<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u8fd9\u4e0d\u662f\u4e3a\u4e86\u201c\u60e9\u7f5a\u5ba2\u6237\u7aef\u201d&#xff0c;\u800c\u662f\u4e3a\u4e86\u4fdd\u62a4\u6574\u4e2a\u8fdb\u7a0b\u4e0d\u88ab\u5355\u4e2a\u8fde\u63a5\u8017\u5c3d\u5185\u5b58\u3002<\/p>\n<hr \/>\n<h2>\u7b2c\u5341\u90e8\u5206&#xff1a;ET\u3001\u516c\u5e73\u9884\u7b97\u548c EPOLLONESHOT<\/h2>\n<h3>\u5341\u516b\u3001\u4e3a\u4ec0\u4e48\u4e0d\u80fd\u65e0\u9650\u6392\u7a7a\u4e00\u4e2a\u975e\u5e38\u6d3b\u8dc3\u7684\u8fde\u63a5<\/h3>\n<p>ET \u7684\u7ecf\u5178\u89c4\u5219\u662f\u201c\u4e00\u76f4\u5904\u7406\u5230 EAGAIN\u201d\u3002<\/p>\n<p>\u4f46\u5982\u679c\u67d0\u4e2a\u5ba2\u6237\u7aef\u6301\u7eed\u9ad8\u901f\u53d1\u9001&#xff0c;\u5355\u7ebf\u7a0b\u53ef\u80fd\u957f\u671f\u505c\u7559\u5728\u8be5\u8fde\u63a5\u7684\u8bfb\u53d6\u5faa\u73af\u4e2d&#xff1a;<\/p>\n<p>fd&#061;7 \u6301\u7eed\u6709\u6570\u636e<br \/>\n    \u2502<br \/>\n    \u25bc<br \/>\n\u4e0d\u65ad recv()<br \/>\n    \u2502<br \/>\n    \u25bc<br \/>\nfd&#061;8\u3001fd&#061;9 \u957f\u65f6\u95f4\u5f97\u4e0d\u5230\u5904\u7406<\/p>\n<p>\u8fd9\u53eb \u4e8b\u4ef6\u5faa\u73af\u9965\u997f\u3002<\/p>\n<p>\u4e00\u79cd\u5de5\u7a0b\u5316\u505a\u6cd5\u662f\u7ed9\u6bcf\u4e2a\u4e8b\u4ef6\u8bbe\u7f6e\u9884\u7b97&#xff1a;<\/p>\n<p>\u6bcf\u6b21\u6700\u591a\u8bfb\u53d6 64 KiB<br \/>\n\u6bcf\u6b21\u6700\u591a\u53d1\u9001 64 KiB<\/p>\n<p>\u9884\u7b97\u8017\u5c3d\u540e&#xff0c;\u628a\u63a7\u5236\u6743\u4ea4\u56de\u4e8b\u4ef6\u5faa\u73af&#xff0c;\u8ba9\u5176\u4ed6\u5c31\u7eea\u8fde\u63a5\u83b7\u5f97\u5904\u7406\u673a\u4f1a\u3002<\/p>\n<h3>\u5341\u4e5d\u3001ET \u4e0b\u63d0\u524d\u505c\u6b62\u8bfb\u53d6\u4e3a\u4ec0\u4e48\u5371\u9669<\/h3>\n<p>\u5982\u679c\u4f7f\u7528\u666e\u901a ET&#xff1a;<\/p>\n<p>\u8bfb\u4e86 64 KiB<br \/>\n\u4f46\u8fd8\u6ca1\u6709\u8bfb\u5230 EAGAIN<br \/>\n\u76f4\u63a5\u8fd4\u56de epoll_wait<\/p>\n<p>\u63a5\u6536\u7f13\u51b2\u533a\u4ecd\u7136\u53ef\u8bfb&#xff0c;\u5374\u4e0d\u4e00\u5b9a\u51fa\u73b0\u65b0\u7684\u8fb9\u7f18\u901a\u77e5&#xff0c;\u8fde\u63a5\u53ef\u80fd\u505c\u6ede\u3002<\/p>\n<p>\u89e3\u51b3\u65b9\u6cd5\u4e4b\u4e00\u662f&#xff1a;<\/p>\n<ul>\n<li>\u4f7f\u7528\u7528\u6237\u6001\u5c31\u7eea\u961f\u5217&#xff1b;<\/li>\n<li>\u6216\u4f7f\u7528 EPOLLONESHOT&#xff0c;\u5904\u7406\u540e\u901a\u8fc7 EPOLL_CTL_MOD \u91cd\u65b0\u6fc0\u6d3b\u3002<\/li>\n<\/ul>\n<p>\u672c\u6587\u6700\u7ec8\u5c42\u91c7\u7528\u7b2c\u4e8c\u79cd\u65b9\u6848\u3002<\/p>\n<h3>\u4e8c\u5341\u3001EPOLLONESHOT \u7684\u8bed\u4e49<\/h3>\n<p>\u6ce8\u518c&#xff1a;<\/p>\n<p>EPOLLIN <span class=\"token operator\">|<\/span> EPOLLET <span class=\"token operator\">|<\/span> EPOLLONESHOT<\/p>\n<p>\u4e8b\u4ef6\u88ab epoll_wait() \u4ea4\u4ed8\u540e&#xff0c;\u8fd9\u4e2a\u76d1\u63a7\u9879\u6682\u65f6\u7981\u7528\u3002<\/p>\n<p>\u5e94\u7528\u5904\u7406\u5b8c\u6210\u540e\u5fc5\u987b&#xff1a;<\/p>\n<p><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n          EPOLL_CTL_MOD<span class=\"token punctuation\">,<\/span><br \/>\n          fd<span class=\"token punctuation\">,<\/span><br \/>\n          <span class=\"token operator\">&amp;<\/span>new_event<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u91cd\u65b0\u6fc0\u6d3b\u3002<\/p>\n<p>\u8fd9\u5e26\u6765\u4e24\u4e2a\u4f5c\u7528&#xff1a;<\/p>\n<li>\u53ef\u4ee5\u5728\u6bcf\u8f6e\u5904\u7406\u540e\u91cd\u65b0\u8ba1\u7b97\u6700\u65b0\u4e8b\u4ef6\u63a9\u7801&#xff1b;<\/li>\n<li>\u591a\u7ebf\u7a0b\u6a21\u578b\u4e2d&#xff0c;\u53ef\u4ee5\u907f\u514d\u540c\u4e00\u76d1\u63a7\u9879\u5728\u672a\u91cd\u65b0\u6fc0\u6d3b\u524d\u88ab\u91cd\u590d\u4ea4\u4ed8&#xff0c;\u4f46\u5e94\u7528\u4ecd\u9700\u6b63\u786e\u7ba1\u7406\u8fde\u63a5\u5bf9\u8c61\u751f\u547d\u5468\u671f\u548c\u5e76\u53d1\u72b6\u6001&#xff0c;\u4e0d\u80fd\u628a EPOLLONESHOT \u7b80\u5316\u6210\u201c\u81ea\u52a8\u7ebf\u7a0b\u5b89\u5168\u201d\u3002<\/li>\n<hr \/>\n<h2>\u7b2c\u5341\u4e00\u90e8\u5206&#xff1a;\u7b2c 5 \u5c42\u2014\u2014\u80cc\u538b\u3001\u9884\u7b97\u4e0e\u8d44\u6e90\u8fb9\u754c<\/h2>\n<h3>\u4e8c\u5341\u4e00\u3001\u6700\u7ec8\u5c42\u7684\u72b6\u6001\u5b57\u6bb5<\/h3>\n<p><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">ClientState<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string output<span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>size_t sent_offset<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">bool<\/span> peer_closed_write<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">bool<\/span> read_paused<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5176\u4e2d&#xff1a;<\/p>\n<table>\n<tr>\u5b57\u6bb5\u542b\u4e49<\/tr>\n<tbody>\n<tr>\n<td>output<\/td>\n<td>\u5df2\u751f\u6210\u4f46\u5c1a\u672a\u5b8c\u5168\u53d1\u9001\u7684\u6570\u636e<\/td>\n<\/tr>\n<tr>\n<td>sent_offset<\/td>\n<td>output \u4e2d\u5df2\u7ecf\u53d1\u9001\u7684\u524d\u7f00\u957f\u5ea6<\/td>\n<\/tr>\n<tr>\n<td>peer_closed_write<\/td>\n<td>recv() \u5df2\u8fd4\u56de 0<\/td>\n<\/tr>\n<tr>\n<td>read_paused<\/td>\n<td>\u56e0\u5f85\u53d1\u9001\u6570\u636e\u8fc7\u591a\u800c\u6682\u505c\u76d1\u542c EPOLLIN<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>21.1 \u5b8c\u6574\u670d\u52a1\u7aef&#xff1a;05_epoll_et_backpressure\/server.cpp<\/h3>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;arpa\/inet.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;fcntl.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/epoll.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/socket.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unistd.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;algorithm&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cerrno&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstdio&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;iostream&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;string&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unordered_map&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;vector&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">namespace<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> <span class=\"token keyword\">uint16_t<\/span> kPort <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">8888<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> <span class=\"token keyword\">int<\/span> kBacklog <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">256<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> <span class=\"token keyword\">int<\/span> kMaxEvents <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">128<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t kBufferSize <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">16<\/span> <span class=\"token operator\">*<\/span> <span class=\"token number\">1024<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">constexpr<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t kMaxClients <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">10000<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t kReadBudgetPerEvent <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">64<\/span> <span class=\"token operator\">*<\/span> <span class=\"token number\">1024<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t kWriteBudgetPerEvent <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">64<\/span> <span class=\"token operator\">*<\/span> <span class=\"token number\">1024<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">constexpr<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t kOutputLowWatermark <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">128<\/span> <span class=\"token operator\">*<\/span> <span class=\"token number\">1024<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t kOutputHighWatermark <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">256<\/span> <span class=\"token operator\">*<\/span> <span class=\"token number\">1024<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t kOutputHardLimit <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1024<\/span> <span class=\"token operator\">*<\/span> <span class=\"token number\">1024<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">ClientState<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string peer<span class=\"token punctuation\">;<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>string output<span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>size_t sent_offset <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">bool<\/span> peer_closed_write <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">bool<\/span> read_paused <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">bool<\/span> <span class=\"token function\">SetNonBlocking<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> old_flags <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> F_GETFL<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>old_flags <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span><br \/>\n                 F_SETFL<span class=\"token punctuation\">,<\/span><br \/>\n                 old_flags <span class=\"token operator\">|<\/span> O_NONBLOCK<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>std<span class=\"token double-colon punctuation\">::<\/span>size_t <span class=\"token function\">PendingBytes<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> ClientState<span class=\"token operator\">&amp;<\/span> client<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#8211;<\/span> client<span class=\"token punctuation\">.<\/span>sent_offset<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">void<\/span> <span class=\"token function\">CompactOutput<\/span><span class=\"token punctuation\">(<\/span>ClientState<span class=\"token operator\">&amp;<\/span> client<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">.<\/span>sent_offset <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">return<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">.<\/span>sent_offset <span class=\"token operator\">&#061;&#061;<\/span> client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">clear<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        client<span class=\"token punctuation\">.<\/span>sent_offset <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">.<\/span>sent_offset <span class=\"token operator\">&gt;&#061;<\/span> <span class=\"token number\">4096<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n        client<span class=\"token punctuation\">.<\/span>sent_offset <span class=\"token operator\">*<\/span> <span class=\"token number\">2<\/span> <span class=\"token operator\">&gt;&#061;<\/span> client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">erase<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">0<\/span><span class=\"token punctuation\">,<\/span> client<span class=\"token punctuation\">.<\/span>sent_offset<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        client<span class=\"token punctuation\">.<\/span>sent_offset <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">uint32_t<\/span> <span class=\"token function\">BuildClientEvents<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> ClientState<span class=\"token operator\">&amp;<\/span> client<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">uint32_t<\/span> events <span class=\"token operator\">&#061;<\/span><br \/>\n        EPOLLET <span class=\"token operator\">|<\/span> EPOLLONESHOT <span class=\"token operator\">|<\/span> EPOLLRDHUP<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>client<span class=\"token punctuation\">.<\/span>peer_closed_write <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n        <span class=\"token operator\">!<\/span>client<span class=\"token punctuation\">.<\/span>read_paused<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        events <span class=\"token operator\">|&#061;<\/span> EPOLLIN<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">PendingBytes<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        events <span class=\"token operator\">|&#061;<\/span> EPOLLOUT<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> events<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">bool<\/span> <span class=\"token function\">RearmClient<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                 <span class=\"token keyword\">int<\/span> client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                 <span class=\"token keyword\">const<\/span> ClientState<span class=\"token operator\">&amp;<\/span> client<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    epoll_event event<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    event<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">BuildClientEvents<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    event<span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd <span class=\"token operator\">&#061;<\/span> client_fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  EPOLL_CTL_MOD<span class=\"token punctuation\">,<\/span><br \/>\n                  client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token operator\">&amp;<\/span>event<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_ctl(MOD\/rearm)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">void<\/span> <span class=\"token function\">CloseClient<\/span><span class=\"token punctuation\">(<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> client_fd<span class=\"token punctuation\">,<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>unordered_map<span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token punctuation\">,<\/span> ClientState<span class=\"token operator\">&gt;<\/span><span class=\"token operator\">&amp;<\/span> clients<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  EPOLL_CTL_DEL<span class=\"token punctuation\">,<\/span><br \/>\n                  client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n        errno <span class=\"token operator\">!&#061;<\/span> ENOENT <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n        errno <span class=\"token operator\">!&#061;<\/span> EBADF<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_ctl(DEL)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">erase<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;closed fd&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> client_fd <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">bool<\/span> <span class=\"token function\">QueueEcho<\/span><span class=\"token punctuation\">(<\/span>ClientState<span class=\"token operator\">&amp;<\/span> client<span class=\"token punctuation\">,<\/span><br \/>\n               <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">char<\/span><span class=\"token operator\">*<\/span> data<span class=\"token punctuation\">,<\/span><br \/>\n               std<span class=\"token double-colon punctuation\">::<\/span>size_t size<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token function\">CompactOutput<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">PendingBytes<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#043;<\/span> size <span class=\"token operator\">&gt;<\/span><br \/>\n        kOutputHardLimit<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">append<\/span><span class=\"token punctuation\">(<\/span>data<span class=\"token punctuation\">,<\/span> size<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">PendingBytes<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&gt;&#061;<\/span><br \/>\n        kOutputHighWatermark<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        client<span class=\"token punctuation\">.<\/span>read_paused <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">bool<\/span> <span class=\"token function\">FlushOutput<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                 ClientState<span class=\"token operator\">&amp;<\/span> client<span class=\"token punctuation\">,<\/span><br \/>\n                 std<span class=\"token double-colon punctuation\">::<\/span>size_t budget<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>size_t written_this_round <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">.<\/span>sent_offset <span class=\"token operator\">&lt;<\/span> client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n           written_this_round <span class=\"token operator\">&lt;<\/span> budget<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span>size_t remain <span class=\"token operator\">&#061;<\/span><br \/>\n            client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#8211;<\/span> client<span class=\"token punctuation\">.<\/span>sent_offset<span class=\"token punctuation\">;<\/span><\/p>\n<p>        std<span class=\"token double-colon punctuation\">::<\/span>size_t allowed <span class=\"token operator\">&#061;<\/span><br \/>\n            std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">min<\/span><span class=\"token punctuation\">(<\/span>remain<span class=\"token punctuation\">,<\/span><br \/>\n                     budget <span class=\"token operator\">&#8211;<\/span> written_this_round<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        ssize_t n <span class=\"token operator\">&#061;<\/span><br \/>\n            <span class=\"token function\">send<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                 client<span class=\"token punctuation\">.<\/span>output<span class=\"token punctuation\">.<\/span><span class=\"token function\">data<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#043;<\/span><br \/>\n                     client<span class=\"token punctuation\">.<\/span>sent_offset<span class=\"token punctuation\">,<\/span><br \/>\n                 allowed<span class=\"token punctuation\">,<\/span><br \/>\n                 MSG_NOSIGNAL<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            std<span class=\"token double-colon punctuation\">::<\/span>size_t written <span class=\"token operator\">&#061;<\/span><br \/>\n                <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            client<span class=\"token punctuation\">.<\/span>sent_offset <span class=\"token operator\">&#043;&#061;<\/span> written<span class=\"token punctuation\">;<\/span><br \/>\n            written_this_round <span class=\"token operator\">&#043;&#061;<\/span> written<span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n            <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EAGAIN <span class=\"token operator\">||<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EWOULDBLOCK<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;send&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">CompactOutput<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">.<\/span>read_paused <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n        <span class=\"token function\">PendingBytes<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&lt;&#061;<\/span><br \/>\n            kOutputLowWatermark<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        client<span class=\"token punctuation\">.<\/span>read_paused <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> listen_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">socket<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n                           SOCK_STREAM <span class=\"token operator\">|<\/span> SOCK_CLOEXEC<span class=\"token punctuation\">,<\/span><br \/>\n                           <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>listen_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;socket&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">SetNonBlocking<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;fcntl(listen_fd)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">int<\/span> reuse <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">setsockopt<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n                   SOL_SOCKET<span class=\"token punctuation\">,<\/span><br \/>\n                   SO_REUSEADDR<span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token operator\">&amp;<\/span>reuse<span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>reuse<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;setsockopt&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    sockaddr_in server_addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_family <span class=\"token operator\">&#061;<\/span> AF_INET<span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">.<\/span>s_addr <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htonl<\/span><span class=\"token punctuation\">(<\/span>INADDR_ANY<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_port <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htons<\/span><span class=\"token punctuation\">(<\/span>kPort<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">bind<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n             <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n             <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;bind&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">listen<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span> kBacklog<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;listen&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">int<\/span> epoll_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">epoll_create1<\/span><span class=\"token punctuation\">(<\/span>EPOLL_CLOEXEC<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>epoll_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_create1&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    epoll_event listen_event<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    listen_event<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span> EPOLLIN <span class=\"token operator\">|<\/span> EPOLLET<span class=\"token punctuation\">;<\/span><br \/>\n    listen_event<span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd <span class=\"token operator\">&#061;<\/span> listen_fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  EPOLL_CTL_ADD<span class=\"token punctuation\">,<\/span><br \/>\n                  listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token operator\">&amp;<\/span>listen_event<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_ctl(ADD listen_fd)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>vector<span class=\"token operator\">&lt;<\/span>epoll_event<span class=\"token operator\">&gt;<\/span> <span class=\"token function\">ready_events<\/span><span class=\"token punctuation\">(<\/span>kMaxEvents<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>unordered_map<span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token punctuation\">,<\/span> ClientState<span class=\"token operator\">&gt;<\/span> clients<span class=\"token punctuation\">;<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>cout<br \/>\n        <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;epoll ET backpressure server listening on 0.0.0.0:&#034;<\/span><br \/>\n        <span class=\"token operator\">&lt;&lt;<\/span> kPort <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">int<\/span> ready_count <span class=\"token operator\">&#061;<\/span><br \/>\n            <span class=\"token function\">epoll_wait<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                       ready_events<span class=\"token punctuation\">.<\/span><span class=\"token function\">data<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                       <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>ready_events<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                       <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>ready_count <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;epoll_wait&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> ready_count<span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>i<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">int<\/span> current_fd <span class=\"token operator\">&#061;<\/span> ready_events<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd<span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">uint32_t<\/span> events <span class=\"token operator\">&#061;<\/span> ready_events<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>events<span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>current_fd <span class=\"token operator\">&#061;&#061;<\/span> listen_fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    sockaddr_in client_addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    socklen_t client_len <span class=\"token operator\">&#061;<\/span><br \/>\n                        <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>client_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">int<\/span> client_fd <span class=\"token operator\">&#061;<\/span><br \/>\n                        <span class=\"token function\">accept<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span><br \/>\n                               <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><br \/>\n                                   <span class=\"token operator\">&amp;<\/span>client_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                               <span class=\"token operator\">&amp;<\/span>client_len<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>client_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR <span class=\"token operator\">||<\/span><br \/>\n                            errno <span class=\"token operator\">&#061;&#061;<\/span> ECONNABORTED<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token punctuation\">}<\/span><\/p>\n<p>                        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EAGAIN <span class=\"token operator\">||<\/span><br \/>\n                            errno <span class=\"token operator\">&#061;&#061;<\/span> EWOULDBLOCK<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token punctuation\">}<\/span><\/p>\n<p>                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;accept&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&gt;&#061;<\/span> kMaxClients<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span>cerr<br \/>\n                            <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;reject fd&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> client_fd<br \/>\n                            <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;: client limit reached\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">SetNonBlocking<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;fcntl(client_fd)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">char<\/span> ip<span class=\"token punctuation\">[<\/span>INET_ADDRSTRLEN<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token function\">inet_ntop<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n                              <span class=\"token operator\">&amp;<\/span>client_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">,<\/span><br \/>\n                              ip<span class=\"token punctuation\">,<\/span><br \/>\n                              <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>ip<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    ClientState client<span class=\"token punctuation\">;<\/span><br \/>\n                    client<span class=\"token punctuation\">.<\/span>peer <span class=\"token operator\">&#061;<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">string<\/span><span class=\"token punctuation\">(<\/span>ip<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#043;<\/span> <span class=\"token string\">&#034;:&#034;<\/span> <span class=\"token operator\">&#043;<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">to_string<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                            <span class=\"token function\">ntohs<\/span><span class=\"token punctuation\">(<\/span>client_addr<span class=\"token punctuation\">.<\/span>sin_port<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    epoll_event client_event<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    client_event<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span><br \/>\n                        <span class=\"token function\">BuildClientEvents<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    client_event<span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd <span class=\"token operator\">&#061;<\/span> client_fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                                  EPOLL_CTL_ADD<span class=\"token punctuation\">,<\/span><br \/>\n                                  client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                                  <span class=\"token operator\">&amp;<\/span>client_event<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                            <span class=\"token string\">&#034;epoll_ctl(ADD client)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;connected: &#034;<\/span><br \/>\n                              <span class=\"token operator\">&lt;&lt;<\/span> client<span class=\"token punctuation\">.<\/span>peer<br \/>\n                              <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;, fd&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> client_fd <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">emplace<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">,<\/span><br \/>\n                                    std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">move<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><\/p>\n<p>                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">auto<\/span> it <span class=\"token operator\">&#061;<\/span> clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">find<\/span><span class=\"token punctuation\">(<\/span>current_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>it <span class=\"token operator\">&#061;&#061;<\/span> clients<span class=\"token punctuation\">.<\/span><span class=\"token function\">end<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            ClientState<span class=\"token operator\">&amp;<\/span> client <span class=\"token operator\">&#061;<\/span> it<span class=\"token operator\">-&gt;<\/span>second<span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">bool<\/span> close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>events <span class=\"token operator\">&amp;<\/span> EPOLLERR<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">0U<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">int<\/span> socket_error <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                socklen_t error_len <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>socket_error<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token function\">getsockopt<\/span><span class=\"token punctuation\">(<\/span>current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                           SOL_SOCKET<span class=\"token punctuation\">,<\/span><br \/>\n                           SO_ERROR<span class=\"token punctuation\">,<\/span><br \/>\n                           <span class=\"token operator\">&amp;<\/span>socket_error<span class=\"token punctuation\">,<\/span><br \/>\n                           <span class=\"token operator\">&amp;<\/span>error_len<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                std<span class=\"token double-colon punctuation\">::<\/span>cerr <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;socket error on fd&#061;&#034;<\/span><br \/>\n                          <span class=\"token operator\">&lt;&lt;<\/span> current_fd<br \/>\n                          <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;: errno&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> socket_error<br \/>\n                          <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>close_now <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n                <span class=\"token operator\">!<\/span>client<span class=\"token punctuation\">.<\/span>read_paused <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n                <span class=\"token punctuation\">(<\/span>events <span class=\"token operator\">&amp;<\/span><br \/>\n                 <span class=\"token punctuation\">(<\/span>EPOLLIN <span class=\"token operator\">|<\/span> EPOLLRDHUP <span class=\"token operator\">|<\/span> EPOLLHUP<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">0U<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span>size_t read_this_round <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span>read_this_round <span class=\"token operator\">&lt;<\/span><br \/>\n                       kReadBudgetPerEvent<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span>kBufferSize<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    std<span class=\"token double-colon punctuation\">::<\/span>size_t allowed <span class=\"token operator\">&#061;<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">min<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                            <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                            kReadBudgetPerEvent <span class=\"token operator\">&#8211;<\/span><br \/>\n                                read_this_round<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                                     buffer<span class=\"token punctuation\">,<\/span><br \/>\n                                     allowed<span class=\"token punctuation\">,<\/span><br \/>\n                                     <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        std<span class=\"token double-colon punctuation\">::<\/span>size_t received <span class=\"token operator\">&#061;<\/span><br \/>\n                            <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">QueueEcho<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">,<\/span><br \/>\n                                       buffer<span class=\"token punctuation\">,<\/span><br \/>\n                                       received<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                            std<span class=\"token double-colon punctuation\">::<\/span>cerr<br \/>\n                                <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;fd&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> current_fd<br \/>\n                                <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034; output hard limit exceeded\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                            close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token punctuation\">}<\/span><\/p>\n<p>                        read_this_round <span class=\"token operator\">&#043;&#061;<\/span> received<span class=\"token punctuation\">;<\/span><\/p>\n<p>                        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">.<\/span>read_paused<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token punctuation\">}<\/span><\/p>\n<p>                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        client<span class=\"token punctuation\">.<\/span>peer_closed_write <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EAGAIN <span class=\"token operator\">||<\/span><br \/>\n                        errno <span class=\"token operator\">&#061;&#061;<\/span> EWOULDBLOCK<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;recv&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token comment\">\/\/ \u4e0d\u76f4\u63a5\u628a EPOLLRDHUP\/EPOLLHUP \u7b49\u540c\u4e8e\u201c\u6240\u6709\u6570\u636e\u5df2\u8bfb\u5b8c\u201d\u3002<\/span><br \/>\n            <span class=\"token comment\">\/\/ FIN \u524d\u9762\u4ecd\u53ef\u80fd\u6392\u7740\u4e1a\u52a1\u6570\u636e&#xff1b;\u53ea\u6709 recv() \u8fd4\u56de 0 \u624d\u786e\u8ba4 EOF\u3002<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>close_now <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n                <span class=\"token function\">PendingBytes<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">FlushOutput<\/span><span class=\"token punctuation\">(<\/span>current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                                 client<span class=\"token punctuation\">,<\/span><br \/>\n                                 kWriteBudgetPerEvent<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>close_now <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n                client<span class=\"token punctuation\">.<\/span>peer_closed_write <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n                <span class=\"token function\">PendingBytes<\/span><span class=\"token punctuation\">(<\/span>client<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                close_now <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>close_now<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token function\">CloseClient<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                            current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                            clients<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token comment\">\/\/ EPOLLONESHOT \u5728\u4e8b\u4ef6\u4ea4\u4ed8\u540e\u4f1a\u7981\u7528\u8be5 fd\u3002<\/span><br \/>\n            <span class=\"token comment\">\/\/ \u8fd9\u91cc\u901a\u8fc7 MOD \u91cd\u65b0\u6fc0\u6d3b&#xff0c;\u540c\u65f6\u5199\u5165\u6700\u65b0\u7684\u8bfb\u5199\u5174\u8da3\u96c6\u5408\u3002<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">RearmClient<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                             current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                             client<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token function\">CloseClient<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n                            current_fd<span class=\"token punctuation\">,<\/span><br \/>\n                            clients<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> <span class=\"token keyword\">auto<\/span><span class=\"token operator\">&amp;<\/span> <span class=\"token punctuation\">[<\/span>client_fd<span class=\"token punctuation\">,<\/span> client<span class=\"token punctuation\">]<\/span> <span class=\"token operator\">:<\/span> clients<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">void<\/span><span class=\"token punctuation\">)<\/span>client<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>21.2 \u5b8c\u6574\u5ba2\u6237\u7aef&#xff1a;05_epoll_et_backpressure\/client.cpp<\/h3>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;arpa\/inet.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/select.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/socket.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unistd.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cerrno&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstdio&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;iostream&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">namespace<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">bool<\/span> <span class=\"token function\">SendAll<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">char<\/span><span class=\"token operator\">*<\/span> data<span class=\"token punctuation\">,<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t size<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>size_t offset <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span>offset <span class=\"token operator\">&lt;<\/span> size<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">send<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span><br \/>\n                         data <span class=\"token operator\">&#043;<\/span> offset<span class=\"token punctuation\">,<\/span><br \/>\n                         size <span class=\"token operator\">&#8211;<\/span> offset<span class=\"token punctuation\">,<\/span><br \/>\n                         MSG_NOSIGNAL<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            offset <span class=\"token operator\">&#043;&#061;<\/span> <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;send&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> socket_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">socket<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span> SOCK_STREAM<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>socket_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;socket&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    sockaddr_in server_addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_family <span class=\"token operator\">&#061;<\/span> AF_INET<span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_port <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htons<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">8888<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">inet_pton<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token string\">&#034;127.0.0.1&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token operator\">&amp;<\/span>server_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span>cerr <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;invalid IPv4 address\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">connect<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span><br \/>\n                <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;connect&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;connected to 127.0.0.1:8888\\\\n&#034;<\/span><br \/>\n              <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;type text; Ctrl&#043;D stops sending but keeps receiving\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">bool<\/span> stdin_open <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        fd_set read_set<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>stdin_open<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>STDIN_FILENO<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">int<\/span> max_fd <span class=\"token operator\">&#061;<\/span> socket_fd <span class=\"token operator\">&gt;<\/span> STDIN_FILENO<br \/>\n                         <span class=\"token operator\">?<\/span> socket_fd<br \/>\n                         <span class=\"token operator\">:<\/span> STDIN_FILENO<span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">int<\/span> ready <span class=\"token operator\">&#061;<\/span><br \/>\n            <span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span>max_fd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                   <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>ready <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;select&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>stdin_open <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n            <span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span>STDIN_FILENO<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span><span class=\"token number\">4096<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span>STDIN_FILENO<span class=\"token punctuation\">,<\/span><br \/>\n                             buffer<span class=\"token punctuation\">,<\/span><br \/>\n                             <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">SendAll<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span><br \/>\n                             buffer<span class=\"token punctuation\">,<\/span><br \/>\n                             <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                stdin_open <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">shutdown<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span> SHUT_WR<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n                    errno <span class=\"token operator\">!&#061;<\/span> ENOTCONN<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;shutdown&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">!&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;read(stdin)&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span><span class=\"token number\">4096<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span><br \/>\n                             buffer<span class=\"token punctuation\">,<\/span><br \/>\n                             <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                             <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span>cout<span class=\"token punctuation\">.<\/span><span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">,<\/span> n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span>cout<span class=\"token punctuation\">.<\/span><span class=\"token function\">flush<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;\\\\nserver closed connection\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">!&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;recv&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>21.3 \u6700\u7ec8\u5c42\u7684\u4fdd\u62a4\u673a\u5236<\/h3>\n<h4>\u8fde\u63a5\u6570\u4e0a\u9650<\/h4>\n<p><span class=\"token keyword\">constexpr<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t kMaxClients <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">10000<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u771f\u5b9e\u53ef\u652f\u6301\u6570\u91cf\u8fd8\u53d7\u4ee5\u4e0b\u56e0\u7d20\u7ea6\u675f&#xff1a;<\/p>\n<ul>\n<li>RLIMIT_NOFILE&#xff1b;<\/li>\n<li>\u7cfb\u7edf\u7ea7\u6587\u4ef6\u63cf\u8ff0\u7b26\u9650\u5236&#xff1b;<\/li>\n<li>epoll watch \u9650\u5236&#xff1b;<\/li>\n<li>\u6bcf\u8fde\u63a5\u7528\u6237\u6001\u72b6\u6001&#xff1b;<\/li>\n<li>socket \u7f13\u51b2\u533a&#xff1b;<\/li>\n<li>\u8fdb\u7a0b\u5185\u5b58&#xff1b;<\/li>\n<li>CPU \u548c\u4e1a\u52a1\u5904\u7406\u6210\u672c\u3002<\/li>\n<\/ul>\n<p>\u56e0\u6b64\u201cepoll \u6ca1\u6709 1024 \u9650\u5236\u201d\u4e0d\u7b49\u4e8e\u201c\u53ef\u4ee5\u65e0\u9650\u5efa\u7acb\u8fde\u63a5\u201d\u3002<\/p>\n<h4>\u5355\u8fde\u63a5\u53d1\u9001\u961f\u5217\u786c\u4e0a\u9650<\/h4>\n<p><span class=\"token keyword\">constexpr<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t kOutputHardLimit <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1024<\/span> <span class=\"token operator\">*<\/span> <span class=\"token number\">1024<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5355\u4e2a\u5ba2\u6237\u7aef\u4e0d\u80fd\u65e0\u9650\u5360\u7528\u5185\u5b58\u3002<\/p>\n<h4>\u9ad8\u4f4e\u6c34\u4f4d\u80cc\u538b<\/h4>\n<p><span class=\"token keyword\">constexpr<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t kOutputLowWatermark <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">128<\/span> <span class=\"token operator\">*<\/span> <span class=\"token number\">1024<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t kOutputHighWatermark <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">256<\/span> <span class=\"token operator\">*<\/span> <span class=\"token number\">1024<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u9ad8\u6c34\u4f4d\u6682\u505c\u8bfb\u53d6&#xff0c;\u4f4e\u6c34\u4f4d\u6062\u590d\u8bfb\u53d6\u3002<\/p>\n<h4>\u6bcf\u4e8b\u4ef6\u8bfb\u5199\u9884\u7b97<\/h4>\n<p><span class=\"token keyword\">constexpr<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t kReadBudgetPerEvent <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">64<\/span> <span class=\"token operator\">*<\/span> <span class=\"token number\">1024<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">constexpr<\/span> std<span class=\"token double-colon punctuation\">::<\/span>size_t kWriteBudgetPerEvent <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">64<\/span> <span class=\"token operator\">*<\/span> <span class=\"token number\">1024<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u9632\u6b62\u4e00\u4e2a\u6d3b\u8dc3\u8fde\u63a5\u957f\u65f6\u95f4\u72ec\u5360\u4e8b\u4ef6\u5faa\u73af\u3002<\/p>\n<h4>EPOLLONESHOT \u91cd\u88c5<\/h4>\n<p>\u6bcf\u8f6e\u5904\u7406\u7ed3\u675f\u540e&#xff1a;<\/p>\n<p><span class=\"token function\">RearmClient<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span> fd<span class=\"token punctuation\">,<\/span> client<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u628a\u6700\u65b0\u7684\u8bfb\u53d6\u3001\u5199\u5165\u3001\u6682\u505c\u72b6\u6001\u91cd\u65b0\u63d0\u4ea4\u7ed9 epoll\u3002<\/p>\n<h3>21.4 \u6700\u7ec8\u5c42\u5b8c\u6574\u6d41\u7a0b\u56fe<\/h3>\n<p>\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510<br \/>\n\u2502                         epoll_wait                           \u2502<br \/>\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518<br \/>\n                               \u2502<br \/>\n                               \u25bc<br \/>\n                    \u53d6\u51fa\u672c\u8f6e\u5c31\u7eea epoll_event<br \/>\n                               \u2502<br \/>\n             \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510<br \/>\n             \u2502                                    \u2502<br \/>\n             \u25bc                                    \u25bc<br \/>\n      fd &#061;&#061; listen_fd                        client fd<br \/>\n             \u2502                                    \u2502<br \/>\n             \u25bc                                    \u25bc<br \/>\n  \u5faa\u73af accept \u5230 EAGAIN                    \u68c0\u67e5 EPOLLERR<br \/>\n             \u2502                                    \u2502<br \/>\n             \u25bc                                    \u25bc<br \/>\n  \u65b0 fd \u8bbe\u7f6e\u975e\u963b\u585e                     \u6309\u9884\u7b97\u5faa\u73af recv<br \/>\n             \u2502                                    \u2502<br \/>\n             \u25bc                                    \u25bc<br \/>\n  \u6ce8\u518c EPOLLIN\/ET                     \u6570\u636e\u52a0\u5165 output<br \/>\n                                                  \u2502<br \/>\n                                                  \u25bc<br \/>\n                                       \u8fbe\u5230\u9ad8\u6c34\u4f4d&#xff1f;<br \/>\n                                         \u2502       \u2502<br \/>\n                                        \u662f       \u5426<br \/>\n                                         \u2502       \u2502<br \/>\n                                         \u25bc       \u25bc<br \/>\n                                     \u6682\u505c\u8bfb    \u7ee7\u7eed\u8bfb<br \/>\n                                                  \u2502<br \/>\n                                                  \u25bc<br \/>\n                                      \u6309\u9884\u7b97\u5faa\u73af send<br \/>\n                                                  \u2502<br \/>\n                          \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510<br \/>\n                          \u2502                                     \u2502<br \/>\n                          \u25bc                                     \u25bc<br \/>\n                      \u5168\u90e8\u53d1\u5b8c                           EAGAIN\/\u9884\u7b97\u8017\u5c3d<br \/>\n                          \u2502                                     \u2502<br \/>\n                          \u25bc                                     \u25bc<br \/>\n                   \u79fb\u9664 EPOLLOUT                        \u4fdd\u7559 EPOLLOUT<br \/>\n                          \u2502<br \/>\n                          \u25bc<br \/>\n             \u4f4e\u4e8e\u4f4e\u6c34\u4f4d\u65f6\u6062\u590d EPOLLIN<br \/>\n                          \u2502<br \/>\n                          \u25bc<br \/>\n              EPOLL_CTL_MOD \u91cd\u65b0\u6fc0\u6d3b ONESHOT<\/p>\n<hr \/>\n<h2>\u7b2c\u5341\u4e8c\u90e8\u5206&#xff1a;epoll \u4e09\u5927 API \u9010\u9879\u89e3\u6790<\/h2>\n<h3>\u4e8c\u5341\u4e8c\u3001epoll_create1()<\/h3>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">epoll_create1<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> flags<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u63a8\u8350&#xff1a;<\/p>\n<p><span class=\"token keyword\">int<\/span> epoll_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">epoll_create1<\/span><span class=\"token punctuation\">(<\/span>EPOLL_CLOEXEC<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>EPOLL_CLOEXEC \u53ef\u4ee5\u907f\u514d\u7a0b\u5e8f\u4ee5\u540e\u8c03\u7528 exec() \u65f6\u610f\u5916\u628a epoll fd \u6cc4\u6f0f\u5230\u65b0\u7a0b\u5e8f\u3002<\/p>\n<p>\u8fd4\u56de\u503c&#xff1a;<\/p>\n<p>&gt;&#061; 0  epoll \u5b9e\u4f8b\u6587\u4ef6\u63cf\u8ff0\u7b26<br \/>\n-1    \u5931\u8d25&#xff0c;\u68c0\u67e5 errno<\/p>\n<h3>\u4e8c\u5341\u4e09\u3001epoll_ctl()<\/h3>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n              <span class=\"token keyword\">int<\/span> operation<span class=\"token punctuation\">,<\/span><br \/>\n              <span class=\"token keyword\">int<\/span> target_fd<span class=\"token punctuation\">,<\/span><br \/>\n              epoll_event<span class=\"token operator\">*<\/span> event<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u4e09\u79cd\u5e38\u7528\u64cd\u4f5c&#xff1a;<\/p>\n<table>\n<tr>\u64cd\u4f5c\u4f5c\u7528<\/tr>\n<tbody>\n<tr>\n<td>EPOLL_CTL_ADD<\/td>\n<td>\u589e\u52a0\u65b0\u7684\u76d1\u63a7\u9879<\/td>\n<\/tr>\n<tr>\n<td>EPOLL_CTL_MOD<\/td>\n<td>\u4fee\u6539\u5df2\u6709\u76d1\u63a7\u9879\u7684\u4e8b\u4ef6\u63a9\u7801\u6216\u7528\u6237\u6570\u636e<\/td>\n<\/tr>\n<tr>\n<td>EPOLL_CTL_DEL<\/td>\n<td>\u5220\u9664\u76d1\u63a7\u9879<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h4>ADD<\/h4>\n<p>epoll_event event<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\nevent<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span> EPOLLIN<span class=\"token punctuation\">;<\/span><br \/>\nevent<span class=\"token punctuation\">.<\/span>data<span class=\"token punctuation\">.<\/span>fd <span class=\"token operator\">&#061;<\/span> client_fd<span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n          EPOLL_CTL_ADD<span class=\"token punctuation\">,<\/span><br \/>\n          client_fd<span class=\"token punctuation\">,<\/span><br \/>\n          <span class=\"token operator\">&amp;<\/span>event<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<h4>MOD<\/h4>\n<p>event<span class=\"token punctuation\">.<\/span>events <span class=\"token operator\">&#061;<\/span> EPOLLIN <span class=\"token operator\">|<\/span> EPOLLOUT <span class=\"token operator\">|<\/span> EPOLLET<span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n          EPOLL_CTL_MOD<span class=\"token punctuation\">,<\/span><br \/>\n          client_fd<span class=\"token punctuation\">,<\/span><br \/>\n          <span class=\"token operator\">&amp;<\/span>event<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<h4>DEL<\/h4>\n<p><span class=\"token function\">epoll_ctl<\/span><span class=\"token punctuation\">(<\/span>epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n          EPOLL_CTL_DEL<span class=\"token punctuation\">,<\/span><br \/>\n          client_fd<span class=\"token punctuation\">,<\/span><br \/>\n          <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>close() \u4f1a\u5728\u76f8\u5173 open file description \u7684\u5f15\u7528\u6700\u7ec8\u6d88\u5931\u65f6\u6e05\u7406 epoll \u5173\u8054&#xff0c;\u4f46\u663e\u5f0f DEL \u53ef\u4ee5\u8ba9\u5355\u7ebf\u7a0b\u793a\u4f8b\u4e2d\u7684\u7528\u6237\u6001\u751f\u547d\u5468\u671f\u66f4\u52a0\u6e05\u695a\u3002\u590d\u6742\u7a0b\u5e8f\u8fd8\u5fc5\u987b\u8003\u8651 dup()\u3001fork() \u548c\u63cf\u8ff0\u7b26\u590d\u7528\u4ea7\u751f\u7684\u5bf9\u8c61\u6240\u6709\u6743\u95ee\u9898\u3002<\/p>\n<h3>\u4e8c\u5341\u56db\u3001epoll_wait()<\/h3>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">epoll_wait<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> epoll_fd<span class=\"token punctuation\">,<\/span><br \/>\n               epoll_event<span class=\"token operator\">*<\/span> events<span class=\"token punctuation\">,<\/span><br \/>\n               <span class=\"token keyword\">int<\/span> max_events<span class=\"token punctuation\">,<\/span><br \/>\n               <span class=\"token keyword\">int<\/span> timeout_ms<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8d85\u65f6\u53c2\u6570&#xff1a;<\/p>\n<table>\n<tr>\u503c\u542b\u4e49<\/tr>\n<tbody>\n<tr>\n<td>-1<\/td>\n<td>\u4e00\u76f4\u7b49\u5f85<\/td>\n<\/tr>\n<tr>\n<td>0<\/td>\n<td>\u4e0d\u7b49\u5f85&#xff0c;\u7acb\u5373\u8fd4\u56de<\/td>\n<\/tr>\n<tr>\n<td>&gt; 0<\/td>\n<td>\u6700\u591a\u7b49\u5f85\u5bf9\u5e94\u6beb\u79d2\u6570<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u8fd4\u56de\u503c&#xff1a;<\/p>\n<table>\n<tr>\u8fd4\u56de\u503c\u542b\u4e49<\/tr>\n<tbody>\n<tr>\n<td>&gt; 0<\/td>\n<td>\u8fd4\u56de\u7684\u5c31\u7eea\u4e8b\u4ef6\u6570\u91cf<\/td>\n<\/tr>\n<tr>\n<td>0<\/td>\n<td>\u8d85\u65f6<\/td>\n<\/tr>\n<tr>\n<td>-1<\/td>\n<td>\u51fa\u9519<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u4fe1\u53f7\u4e2d\u65ad&#xff1a;<\/p>\n<p><span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>count <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u901a\u5e38\u4e0d\u662f\u81f4\u547d\u9519\u8bef\u3002<\/p>\n<hr \/>\n<h2>\u7b2c\u5341\u4e09\u90e8\u5206&#xff1a;\u5e38\u7528\u4e8b\u4ef6\u6807\u5fd7<\/h2>\n<h3>\u4e8c\u5341\u4e94\u3001\u4e8b\u4ef6\u4f4d\u901f\u67e5\u8868<\/h3>\n<table>\n<tr>\u6807\u5fd7\u542b\u4e49\u5e38\u89c1\u5904\u7406<\/tr>\n<tbody>\n<tr>\n<td>EPOLLIN<\/td>\n<td>\u53ef\u80fd\u53ef\u8bfb<\/td>\n<td>accept()\u3001recv()\u3001\u8bfb\u53d6\u7ba1\u9053\u7b49<\/td>\n<\/tr>\n<tr>\n<td>EPOLLOUT<\/td>\n<td>\u53ef\u80fd\u53ef\u5199<\/td>\n<td>\u7ee7\u7eed\u53d1\u9001\u5f85\u53d1\u9001\u961f\u5217<\/td>\n<\/tr>\n<tr>\n<td>EPOLLRDHUP<\/td>\n<td>\u6d41\u5f0f\u8fde\u63a5\u5bf9\u7aef\u5173\u95ed\u5199\u65b9\u5411<\/td>\n<td>\u7ee7\u7eed\u8bfb\u5b8c\u5269\u4f59\u6570\u636e&#xff0c;\u7b49\u5f85 recv()&#061;&#061;0<\/td>\n<\/tr>\n<tr>\n<td>EPOLLERR<\/td>\n<td>\u5f02\u6b65\u9519\u8bef<\/td>\n<td>\u7528 getsockopt(SO_ERROR) \u83b7\u53d6\u9519\u8bef<\/td>\n<\/tr>\n<tr>\n<td>EPOLLHUP<\/td>\n<td>\u6302\u65ad<\/td>\n<td>\u4ecd\u5e94\u8003\u8651\u8bfb\u53d6\u6b8b\u7559\u6570\u636e<\/td>\n<\/tr>\n<tr>\n<td>EPOLLET<\/td>\n<td>\u8fb9\u7f18\u89e6\u53d1<\/td>\n<td>\u975e\u963b\u585e\u5e76\u5904\u7406\u5230 EAGAIN<\/td>\n<\/tr>\n<tr>\n<td>EPOLLONESHOT<\/td>\n<td>\u4e00\u6b21\u4ea4\u4ed8\u540e\u7981\u7528<\/td>\n<td>EPOLL_CTL_MOD \u91cd\u65b0\u6fc0\u6d3b<\/td>\n<\/tr>\n<tr>\n<td>EPOLLEXCLUSIVE<\/td>\n<td>\u67d0\u4e9b\u591a epoll \u7b49\u5f85\u573a\u666f\u7684\u72ec\u5360\u5524\u9192<\/td>\n<td>\u4e3b\u8981\u7528\u4e8e\u7f13\u89e3\u7279\u5b9a\u60ca\u7fa4\u573a\u666f<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>EPOLLERR \u548c EPOLLHUP \u5373\u4f7f\u6ca1\u6709\u663e\u5f0f\u52a0\u5165\u5174\u8da3\u63a9\u7801&#xff0c;\u4e5f\u53ef\u80fd\u88ab\u8fd4\u56de&#xff0c;\u56e0\u6b64\u4e8b\u4ef6\u5faa\u73af\u5fc5\u987b\u5904\u7406\u5b83\u4eec\u3002<\/p>\n<h3>\u4e8c\u5341\u516d\u3001\u4e3a\u4ec0\u4e48\u4f7f\u7528 SO_ERROR<\/h3>\n<p><span class=\"token keyword\">int<\/span> socket_error <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\nsocklen_t error_len <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>socket_error<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token function\">getsockopt<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span><br \/>\n           SOL_SOCKET<span class=\"token punctuation\">,<\/span><br \/>\n           SO_ERROR<span class=\"token punctuation\">,<\/span><br \/>\n           <span class=\"token operator\">&amp;<\/span>socket_error<span class=\"token punctuation\">,<\/span><br \/>\n           <span class=\"token operator\">&amp;<\/span>error_len<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>EPOLLERR \u53ea\u662f\u544a\u8bc9\u4f60\u5957\u63a5\u5b57\u5b58\u5728\u9519\u8bef\u72b6\u6001&#xff0c;SO_ERROR \u624d\u7528\u4e8e\u8bfb\u53d6\u6302\u8d77\u7684\u5177\u4f53\u5957\u63a5\u5b57\u9519\u8bef\u7801\u3002<\/p>\n<hr \/>\n<h2>\u7b2c\u5341\u56db\u90e8\u5206&#xff1a;accept\u3001recv\u3001send \u7684\u5b8c\u6574\u72b6\u6001\u8868<\/h2>\n<h3>\u4e8c\u5341\u4e03\u3001\u975e\u963b\u585e accept<\/h3>\n<table>\n<tr>\u8fd4\u56de\u542b\u4e49<\/tr>\n<tbody>\n<tr>\n<td>fd &gt;&#061; 0<\/td>\n<td>\u6210\u529f\u53d6\u5f97\u4e00\u4e2a\u8fde\u63a5<\/td>\n<\/tr>\n<tr>\n<td>-1, EINTR<\/td>\n<td>\u88ab\u4fe1\u53f7\u4e2d\u65ad&#xff0c;\u91cd\u8bd5<\/td>\n<\/tr>\n<tr>\n<td>-1, ECONNABORTED<\/td>\n<td>\u961f\u5217\u4e2d\u7684\u8fde\u63a5\u5df2\u7ecf\u4e2d\u6b62&#xff0c;\u53ef\u7ee7\u7eed<\/td>\n<\/tr>\n<tr>\n<td>-1, EAGAIN\/EWOULDBLOCK<\/td>\n<td>\u5f53\u524d\u8fde\u63a5\u961f\u5217\u5df2\u6392\u7a7a<\/td>\n<\/tr>\n<tr>\n<td>\u5176\u4ed6\u9519\u8bef<\/td>\n<td>\u8bb0\u5f55\u5e76\u6839\u636e\u7b56\u7565\u5904\u7406<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>\u4e8c\u5341\u516b\u3001\u975e\u963b\u585e recv<\/h3>\n<table>\n<tr>\u8fd4\u56de\u542b\u4e49<\/tr>\n<tbody>\n<tr>\n<td>n &gt; 0<\/td>\n<td>\u6536\u5230 n \u5b57\u8282<\/td>\n<\/tr>\n<tr>\n<td>n &#061;&#061; 0<\/td>\n<td>\u63a5\u6536\u65b9\u5411 EOF<\/td>\n<\/tr>\n<tr>\n<td>-1, EINTR<\/td>\n<td>\u91cd\u8bd5<\/td>\n<\/tr>\n<tr>\n<td>-1, EAGAIN\/EWOULDBLOCK<\/td>\n<td>\u5f53\u524d\u5df2\u65e0\u6570\u636e\u53ef\u8bfb<\/td>\n<\/tr>\n<tr>\n<td>\u5176\u4ed6\u9519\u8bef<\/td>\n<td>\u8fde\u63a5\u5f02\u5e38<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>\u4e8c\u5341\u4e5d\u3001\u975e\u963b\u585e send<\/h3>\n<table>\n<tr>\u8fd4\u56de\u542b\u4e49<\/tr>\n<tbody>\n<tr>\n<td>n &gt; 0<\/td>\n<td>\u53d1\u9001\u4e86 n \u5b57\u8282&#xff0c;\u53ef\u80fd\u5c0f\u4e8e\u8bf7\u6c42\u957f\u5ea6<\/td>\n<\/tr>\n<tr>\n<td>-1, EINTR<\/td>\n<td>\u91cd\u8bd5<\/td>\n<\/tr>\n<tr>\n<td>-1, EAGAIN\/EWOULDBLOCK<\/td>\n<td>\u5f53\u524d\u53d1\u9001\u7f13\u51b2\u533a\u6ee1&#xff0c;\u7b49\u5f85 EPOLLOUT<\/td>\n<\/tr>\n<tr>\n<td>-1, EPIPE<\/td>\n<td>\u5bf9\u7aef\u5df2\u7ecf\u5173\u95ed\u76f8\u5e94\u65b9\u5411<\/td>\n<\/tr>\n<tr>\n<td>\u5176\u4ed6\u9519\u8bef<\/td>\n<td>\u8fde\u63a5\u5f02\u5e38<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<h2>\u7b2c\u5341\u4e94\u90e8\u5206&#xff1a;TCP \u534a\u5173\u95ed<\/h2>\n<h3>\u4e09\u5341\u3001shutdown(SHUT_WR) \u7684\u610f\u4e49<\/h3>\n<p>\u5ba2\u6237\u7aef\u6309\u4e0b Ctrl&#043;D \u540e&#xff0c;\u672c\u6587\u5ba2\u6237\u7aef\u4e0d\u4f1a\u7acb\u5373 close()&#xff0c;\u800c\u662f&#xff1a;<\/p>\n<p><span class=\"token function\">shutdown<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span> SHUT_WR<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8fd9\u8868\u793a&#xff1a;<\/p>\n<p>\u5ba2\u6237\u7aef&#xff1a;<br \/>\n    \u4e0d\u518d\u53d1\u9001\u65b0\u6570\u636e<br \/>\n    \u4f46\u4ecd\u7136\u53ef\u4ee5\u63a5\u6536\u670d\u52a1\u7aef\u6570\u636e<\/p>\n<p>\u5bf9\u5e94\u7684 TCP \u72b6\u6001\u662f\u53d1\u9001 FIN&#xff0c;\u4f46\u8fde\u63a5\u7684\u53e6\u4e00\u4e2a\u65b9\u5411\u4ecd\u53ef\u7ee7\u7eed\u4f20\u8f93\u3002<\/p>\n<p>\u6d41\u7a0b&#xff1a;<\/p>\n<p>\u5ba2\u6237\u7aef\u53d1\u9001\u4e1a\u52a1\u6570\u636e<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\nshutdown(SHUT_WR)<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\n\u670d\u52a1\u7aef\u8bfb\u5230\u4e1a\u52a1\u6570\u636e<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\n\u670d\u52a1\u7aef recv() \u6700\u7ec8\u8fd4\u56de 0<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\n\u670d\u52a1\u7aef\u53d1\u9001\u5b8c\u5269\u4f59\u56de\u663e<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\n\u670d\u52a1\u7aef close()<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\n\u5ba2\u6237\u7aef\u8bfb\u5230\u5168\u90e8\u56de\u663e\u548c EOF<\/p>\n<p>\u8fd9\u4e5f\u662f\u4e3a\u4ec0\u4e48\u670d\u52a1\u7aef\u4e0d\u80fd\u4e00\u770b\u5230 EPOLLRDHUP \u5c31\u7acb\u5373\u4e22\u5f03\u53d1\u9001\u961f\u5217\u5e76\u5173\u95ed\u3002<\/p>\n<hr \/>\n<h2>\u7b2c\u5341\u516d\u90e8\u5206&#xff1a;LT \u4e0e ET \u5e94\u8be5\u5982\u4f55\u9009<\/h2>\n<h3>\u4e09\u5341\u4e00\u3001\u5bf9\u6bd4\u8868<\/h3>\n<table>\n<tr>\u7ef4\u5ea6LTET<\/tr>\n<tbody>\n<tr>\n<td>\u9ed8\u8ba4\u6a21\u5f0f<\/td>\n<td>\u662f<\/td>\n<td>\u5426&#xff0c;\u9700\u8981 EPOLLET<\/td>\n<\/tr>\n<tr>\n<td>\u7f16\u7a0b\u96be\u5ea6<\/td>\n<td>\u8f83\u4f4e<\/td>\n<td>\u8f83\u9ad8<\/td>\n<\/tr>\n<tr>\n<td>\u975e\u963b\u585e\u8981\u6c42<\/td>\n<td>\u5f3a\u70c8\u5efa\u8bae<\/td>\n<td>\u5b9e\u9645\u4f7f\u7528\u4e2d\u5e94\u5f53\u91c7\u7528<\/td>\n<\/tr>\n<tr>\n<td>\u8bfb\u53d6\u7b56\u7565<\/td>\n<td>\u53ef\u4ee5\u5206\u6279\u5904\u7406<\/td>\n<td>\u5fc5\u987b\u786e\u4fdd\u4e0d\u4f1a\u9057\u7559\u672a\u5904\u7406\u5c31\u7eea\u72b6\u6001<\/td>\n<\/tr>\n<tr>\n<td>\u5199\u5165\u7b56\u7565<\/td>\n<td>\u4ecd\u8981\u5904\u7406\u90e8\u5206\u53d1\u9001\u548c EAGAIN<\/td>\n<td>\u540c\u6837\u9700\u8981&#xff0c;\u4e14\u4e8b\u4ef6\u72b6\u6001\u66f4\u654f\u611f<\/td>\n<\/tr>\n<tr>\n<td>\u91cd\u590d\u901a\u77e5<\/td>\n<td>\u6761\u4ef6\u6301\u7eed\u6ee1\u8db3\u65f6\u53ef\u80fd\u91cd\u590d<\/td>\n<td>\u901a\u77e5\u66f4\u4f9d\u8d56\u72b6\u6001\u53d8\u5316<\/td>\n<\/tr>\n<tr>\n<td>\u51fa\u9519\u98ce\u9669<\/td>\n<td>\u76f8\u5bf9\u4f4e<\/td>\n<td>\u5fd8\u8bb0\u6392\u7a7a\u3001\u9519\u8bef\u6682\u505c\u66f4\u5bb9\u6613\u505c\u6ede<\/td>\n<\/tr>\n<tr>\n<td>\u9002\u7528\u573a\u666f<\/td>\n<td>\u5927\u591a\u6570\u670d\u52a1\u7aef\u7684\u5b89\u5168\u8d77\u70b9<\/td>\n<td>\u660e\u786e\u7406\u89e3\u72b6\u6001\u673a\u5e76\u9700\u8981\u7cbe\u7ec6\u63a7\u5236\u65f6<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>\u4e09\u5341\u4e8c\u3001ET \u4e00\u5b9a\u6bd4 LT \u5feb\u5417<\/h3>\n<p>\u4e0d\u4e00\u5b9a\u3002<\/p>\n<p>\u6027\u80fd\u53d6\u51b3\u4e8e&#xff1a;<\/p>\n<ul>\n<li>\u6d3b\u8dc3\u8fde\u63a5\u6bd4\u4f8b&#xff1b;<\/li>\n<li>\u6bcf\u6b21\u4e8b\u4ef6\u7684\u6570\u636e\u91cf&#xff1b;<\/li>\n<li>\u7cfb\u7edf\u8c03\u7528\u9891\u7387&#xff1b;<\/li>\n<li>\u4e1a\u52a1\u5904\u7406\u6210\u672c&#xff1b;<\/li>\n<li>\u7f13\u51b2\u533a\u5927\u5c0f&#xff1b;<\/li>\n<li>\u4e8b\u4ef6\u5faa\u73af\u516c\u5e73\u6027&#xff1b;<\/li>\n<li>\u5185\u5b58\u5206\u914d&#xff1b;<\/li>\n<li>\u9501\u7ade\u4e89&#xff1b;<\/li>\n<li>\u7f51\u7edc\u5ef6\u8fdf&#xff1b;<\/li>\n<li>CPU \u7f13\u5b58\u884c\u4e3a\u3002<\/li>\n<\/ul>\n<p>\u5728\u8bb8\u591a\u670d\u52a1\u4e2d&#xff0c;\u4e1a\u52a1\u903b\u8f91\u3001\u5e8f\u5217\u5316\u3001\u6570\u636e\u5e93\u548c\u65e5\u5fd7\u7684\u6210\u672c\u8fdc\u9ad8\u4e8e LT\/ET \u7684\u5dee\u5f02\u3002<\/p>\n<p>\u9009\u62e9\u539f\u5219\u5e94\u662f&#xff1a;<\/p>\n<p>\u5148\u5b9e\u73b0\u6b63\u786e\u3001\u53ef\u6d4b\u91cf\u7684 LT<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\n\u901a\u8fc7\u6027\u80fd\u5206\u6790\u786e\u8ba4\u4e8b\u4ef6\u8c03\u5ea6\u6210\u4e3a\u74f6\u9888<br \/>\n        \u2502<br \/>\n        \u25bc<br \/>\n\u518d\u8bc4\u4f30 ET \u662f\u5426\u80fd\u5e26\u6765\u5b9e\u9645\u6536\u76ca<\/p>\n<p>\u4e0d\u8981\u4ec5\u51ed\u201cET \u66f4\u9ad8\u7ea7\u201d\u9009\u62e9 ET\u3002<\/p>\n<hr \/>\n<h2>\u7b2c\u5341\u4e03\u90e8\u5206&#xff1a;\u538b\u529b\u6d4b\u8bd5\u5ba2\u6237\u7aef<\/h2>\n<h3>\u4e09\u5341\u4e09\u3001\u5b8c\u6574\u5927\u6570\u636e\u6821\u9a8c\u5ba2\u6237\u7aef<\/h3>\n<p>\u8be5\u5ba2\u6237\u7aef&#xff1a;<\/p>\n<li>\u751f\u6210\u6307\u5b9a\u5927\u5c0f\u7684 X \u5b57\u8282&#xff1b;<\/li>\n<li>\u5b8c\u6574\u53d1\u9001&#xff1b;<\/li>\n<li>shutdown(SHUT_WR)&#xff1b;<\/li>\n<li>\u8bfb\u53d6\u670d\u52a1\u7aef\u5168\u90e8\u56de\u663e&#xff1b;<\/li>\n<li>\u9010\u5b57\u8282\u6821\u9a8c\u3002<\/li>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;arpa\/inet.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/socket.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unistd.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cerrno&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstdio&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;cstdlib&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;iostream&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;string&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">namespace<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">bool<\/span> <span class=\"token function\">SendAll<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span><br \/>\n             <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">char<\/span><span class=\"token operator\">*<\/span> data<span class=\"token punctuation\">,<\/span><br \/>\n             std<span class=\"token double-colon punctuation\">::<\/span>size_t size<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>size_t offset <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span>offset <span class=\"token operator\">&lt;<\/span> size<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">send<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span><br \/>\n                         data <span class=\"token operator\">&#043;<\/span> offset<span class=\"token punctuation\">,<\/span><br \/>\n                         size <span class=\"token operator\">&#8211;<\/span> offset<span class=\"token punctuation\">,<\/span><br \/>\n                         MSG_NOSIGNAL<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            offset <span class=\"token operator\">&#043;&#061;<\/span> <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span> <span class=\"token operator\">&amp;&amp;<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;send&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> argc<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">char<\/span><span class=\"token operator\">*<\/span> argv<span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>size_t message_size <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1024<\/span> <span class=\"token operator\">*<\/span> <span class=\"token number\">1024<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>argc <span class=\"token operator\">&gt;&#061;<\/span> <span class=\"token number\">2<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        message_size <span class=\"token operator\">&#061;<\/span><br \/>\n            <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><br \/>\n                std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">strtoull<\/span><span class=\"token punctuation\">(<\/span>argv<span class=\"token punctuation\">[<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">10<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">int<\/span> socket_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">socket<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span> SOCK_STREAM<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>socket_fd <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;socket&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    sockaddr_in server_addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_family <span class=\"token operator\">&#061;<\/span> AF_INET<span class=\"token punctuation\">;<\/span><br \/>\n    server_addr<span class=\"token punctuation\">.<\/span>sin_port <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">htons<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">8888<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">inet_pton<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token string\">&#034;127.0.0.1&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                  <span class=\"token operator\">&amp;<\/span>server_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span>cerr <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;invalid IPv4 address\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">connect<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span><br \/>\n                <span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>sockaddr<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>server_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;connect&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>string <span class=\"token function\">payload<\/span><span class=\"token punctuation\">(<\/span>message_size<span class=\"token punctuation\">,<\/span> <span class=\"token char\">&#039;X&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span><span class=\"token function\">SendAll<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span><br \/>\n                 payload<span class=\"token punctuation\">.<\/span><span class=\"token function\">data<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                 payload<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">shutdown<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span> SHUT_WR<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;shutdown&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>string received<span class=\"token punctuation\">;<\/span><br \/>\n    received<span class=\"token punctuation\">.<\/span><span class=\"token function\">reserve<\/span><span class=\"token punctuation\">(<\/span>payload<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span><span class=\"token number\">16<\/span> <span class=\"token operator\">*<\/span> <span class=\"token number\">1024<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">,<\/span><br \/>\n                         buffer<span class=\"token punctuation\">,<\/span><br \/>\n                         <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                         <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            received<span class=\"token punctuation\">.<\/span><span class=\"token function\">append<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                buffer<span class=\"token punctuation\">,<\/span><br \/>\n                <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;recv&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>socket_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">bool<\/span> ok <span class=\"token operator\">&#061;<\/span> received <span class=\"token operator\">&#061;&#061;<\/span> payload<span class=\"token punctuation\">;<\/span><\/p>\n<p>    std<span class=\"token double-colon punctuation\">::<\/span>cout <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;sent&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> payload<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><br \/>\n              <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;, received&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> received<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><br \/>\n              <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token string\">&#034;, verify&#061;&#034;<\/span> <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token punctuation\">(<\/span>ok <span class=\"token operator\">?<\/span> <span class=\"token string\">&#034;OK&#034;<\/span> <span class=\"token operator\">:<\/span> <span class=\"token string\">&#034;FAILED&#034;<\/span><span class=\"token punctuation\">)<\/span><br \/>\n              <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> ok <span class=\"token operator\">?<\/span> <span class=\"token number\">0<\/span> <span class=\"token operator\">:<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>33.1 \u6d4b\u8bd5 1 MiB \u56de\u663e<\/h3>\n<p>.\/bin\/05_epoll_et_server<\/p>\n<p>\u53e6\u4e00\u4e2a\u7ec8\u7aef&#xff1a;<\/p>\n<p>.\/bin\/stress_client <span class=\"token number\">1048576<\/span><\/p>\n<p>\u9884\u671f&#xff1a;<\/p>\n<p>sent&#061;1048576, received&#061;1048576, verify&#061;OK<\/p>\n<h3>33.2 \u4e3a\u4ec0\u4e48\u4e0d\u80fd\u7528\u4e00\u6b21 write \u4f5c\u4e3a\u538b\u529b\u6d4b\u8bd5<\/h3>\n<p>\u9519\u8bef\u5199\u6cd5&#xff1a;<\/p>\n<p><span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> big_message<span class=\"token punctuation\">.<\/span><span class=\"token function\">data<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> big_message<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5982\u679c\u8fd4\u56de\u503c\u5c0f\u4e8e big_message.size()&#xff0c;\u5269\u4f59\u6570\u636e\u6ca1\u6709\u88ab\u53d1\u9001\u3002<\/p>\n<p>\u538b\u529b\u6d4b\u8bd5\u672c\u8eab\u4e5f\u5fc5\u987b\u6b63\u786e\u5904\u7406\u90e8\u5206\u53d1\u9001&#xff0c;\u5426\u5219\u65e0\u6cd5\u533a\u5206&#xff1a;<\/p>\n<ul>\n<li>\u670d\u52a1\u7aef\u9519\u8bef&#xff1b;<\/li>\n<li>\u5ba2\u6237\u7aef\u53d1\u9001\u4e0d\u5b8c\u6574\u3002<\/li>\n<\/ul>\n<hr \/>\n<h2>\u7b2c\u5341\u516b\u90e8\u5206&#xff1a;\u7f16\u8bd1\u4e0e\u8fd0\u884c<\/h2>\n<h3>\u4e09\u5341\u56db\u3001\u7f16\u8bd1\u5168\u90e8\u7248\u672c<\/h3>\n<p><span class=\"token function\">make<\/span><\/p>\n<p>\u4f7f\u7528\u7684\u7f16\u8bd1\u53c2\u6570&#xff1a;<\/p>\n<p>g&#043;&#043; <span class=\"token parameter variable\">-std<\/span><span class=\"token operator\">&#061;<\/span>c&#043;&#043;17 <span class=\"token parameter variable\">-O2<\/span> <span class=\"token parameter variable\">-Wall<\/span> <span class=\"token parameter variable\">-Wextra<\/span> <span class=\"token parameter variable\">-Wpedantic<\/span><\/p>\n<h3>\u4e09\u5341\u4e94\u3001\u8fd0\u884c\u6307\u5b9a\u5c42\u6b21<\/h3>\n<h4>\u7b2c 0 \u5c42<\/h4>\n<p>.\/bin\/00_select_server<br \/>\n.\/bin\/00_select_client<\/p>\n<h4>\u7b2c 1 \u5c42<\/h4>\n<p>.\/bin\/01_epoll_lt_server<br \/>\n.\/bin\/01_epoll_lt_client<\/p>\n<h4>\u7b2c 2 \u5c42<\/h4>\n<p>.\/bin\/02_epoll_lt_server<br \/>\n.\/bin\/02_epoll_lt_client<\/p>\n<h4>\u7b2c 3 \u5c42<\/h4>\n<p>.\/bin\/03_epoll_et_server<br \/>\n.\/bin\/03_epoll_et_client<\/p>\n<h4>\u7b2c 4 \u5c42<\/h4>\n<p>.\/bin\/04_epoll_et_server<br \/>\n.\/bin\/04_epoll_et_client<\/p>\n<h4>\u7b2c 5 \u5c42<\/h4>\n<p>.\/bin\/05_epoll_et_server<br \/>\n.\/bin\/05_epoll_et_client<\/p>\n<p>\u5ba2\u6237\u7aef\u8f93\u5165\u7ed3\u675f&#xff1a;<\/p>\n<p>Ctrl&#043;D<\/p>\n<p>\u5ba2\u6237\u7aef\u4f1a\u534a\u5173\u95ed\u5199\u65b9\u5411&#xff0c;\u4f46\u7ee7\u7eed\u8bfb\u53d6\u670d\u52a1\u7aef\u56de\u663e\u3002<\/p>\n<hr \/>\n<h2>\u7b2c\u5341\u4e5d\u90e8\u5206&#xff1a;\u8c03\u8bd5\u65b9\u6cd5<\/h2>\n<h3>\u4e09\u5341\u516d\u3001\u4f7f\u7528 strace \u89c2\u5bdf\u4e8b\u4ef6\u5faa\u73af<\/h3>\n<p><span class=\"token function\">strace<\/span> <span class=\"token parameter variable\">-f<\/span> <span class=\"token punctuation\">\\\\<\/span><br \/>\n  <span class=\"token parameter variable\">-e<\/span> <span class=\"token assign-left variable\">trace<\/span><span class=\"token operator\">&#061;<\/span>epoll_create1,epoll_ctl,epoll_wait,accept,recvfrom,sendto,close <span class=\"token punctuation\">\\\\<\/span><br \/>\n  .\/bin\/05_epoll_et_server<\/p>\n<p>\u91cd\u70b9\u89c2\u5bdf&#xff1a;<\/p>\n<p>epoll_wait(&#8230;)<br \/>\naccept(&#8230;)<br \/>\nrecvfrom(&#8230;)<br \/>\nsendto(&#8230;)<br \/>\nepoll_ctl(&#8230; EPOLL_CTL_MOD &#8230;)<\/p>\n<h3>\u4e09\u5341\u4e03\u3001\u4f7f\u7528 ss \u67e5\u770b\u8fde\u63a5<\/h3>\n<p>ss <span class=\"token parameter variable\">-ltnp<\/span> <span class=\"token string\">&#039;sport &#061; :8888&#039;<\/span><\/p>\n<p>\u67e5\u770b\u76d1\u542c\u72b6\u6001&#xff1a;<\/p>\n<p>LISTEN<\/p>\n<p>\u67e5\u770b\u5df2\u5efa\u7acb\u8fde\u63a5&#xff1a;<\/p>\n<p>ss <span class=\"token parameter variable\">-tnp<\/span> <span class=\"token string\">&#039;sport &#061; :8888 or dport &#061; :8888&#039;<\/span><\/p>\n<h3>\u4e09\u5341\u516b\u3001\u6a21\u62df\u6162\u5ba2\u6237\u7aef<\/h3>\n<p>\u53ef\u4ee5\u8ba9\u5ba2\u6237\u7aef\u53d1\u9001\u5927\u91cf\u6570\u636e&#xff0c;\u5374\u6682\u65f6\u4e0d\u8bfb\u53d6\u56de\u663e&#xff0c;\u4ece\u800c\u89c2\u5bdf&#xff1a;<\/p>\n<ul>\n<li>\u670d\u52a1\u7aef\u53d1\u9001\u961f\u5217\u589e\u957f&#xff1b;<\/li>\n<li>\u8fbe\u5230\u9ad8\u6c34\u4f4d\u540e\u6682\u505c EPOLLIN&#xff1b;<\/li>\n<li>\u53d1\u9001\u961f\u5217\u4e0b\u964d\u540e\u6062\u590d\u8bfb\u53d6&#xff1b;<\/li>\n<li>\u8d85\u8fc7\u786c\u4e0a\u9650\u540e\u7684\u65ad\u5f00\u7b56\u7565\u3002<\/li>\n<\/ul>\n<hr \/>\n<h2>\u7b2c\u4e8c\u5341\u90e8\u5206&#xff1a;\u5e38\u89c1\u9519\u8bef\u6e05\u5355<\/h2>\n<h3>\u4e09\u5341\u4e5d\u3001\u9519\u8bef&#xff1a;ET \u53ea\u52a0 EPOLLET&#xff0c;\u4e0d\u6539\u8bfb\u53d6\u65b9\u5f0f<\/h3>\n<p>events <span class=\"token operator\">&#061;<\/span> EPOLLIN <span class=\"token operator\">|<\/span> EPOLLET<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> buf<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buf<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u53ea\u8bfb\u4e00\u6b21<\/span><\/p>\n<p>\u540e\u679c&#xff1a;\u672a\u8bfb\u6570\u636e\u53ef\u80fd\u6ede\u7559&#xff0c;\u5904\u7406\u505c\u6ede\u3002<\/p>\n<h3>\u56db\u5341\u3001\u9519\u8bef&#xff1a;ET \u4f7f\u7528\u963b\u585e fd \u5faa\u73af\u8bfb<\/h3>\n<p><span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> buf<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buf<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u540e\u679c&#xff1a;\u7f13\u51b2\u533a\u8bfb\u7a7a\u540e\u963b\u585e\u6574\u4e2a\u4e8b\u4ef6\u5faa\u73af\u3002<\/p>\n<h3>\u56db\u5341\u4e00\u3001\u9519\u8bef&#xff1a;\u628a EAGAIN \u5f53\u6210\u8fde\u63a5\u5931\u8d25<\/h3>\n<p><span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u540e\u679c&#xff1a;\u6b63\u5e38\u7684\u975e\u963b\u585e\u63a7\u5236\u6d41\u88ab\u8bef\u5224\u4e3a\u9519\u8bef\u3002<\/p>\n<h3>\u56db\u5341\u4e8c\u3001\u9519\u8bef&#xff1a;\u6c38\u4e45\u76d1\u542c EPOLLOUT<\/h3>\n<p>events <span class=\"token operator\">&#061;<\/span> EPOLLIN <span class=\"token operator\">|<\/span> EPOLLOUT<span class=\"token punctuation\">;<\/span><\/p>\n<p>\u540e\u679c&#xff1a;\u6ca1\u6709\u5f85\u53d1\u9001\u6570\u636e\u65f6\u4ecd\u53ef\u80fd\u6301\u7eed\u88ab\u53ef\u5199\u4e8b\u4ef6\u5524\u9192\u3002<\/p>\n<h3>\u56db\u5341\u4e09\u3001\u9519\u8bef&#xff1a;\u5ffd\u7565\u90e8\u5206\u53d1\u9001<\/h3>\n<p><span class=\"token function\">send<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> data<span class=\"token punctuation\">,<\/span> size<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u540e\u679c&#xff1a;\u53ea\u53d1\u9001\u524d\u534a\u90e8\u5206&#xff0c;\u5e94\u7528\u5374\u4ee5\u4e3a\u5168\u90e8\u5b8c\u6210\u3002<\/p>\n<h3>\u56db\u5341\u56db\u3001\u9519\u8bef&#xff1a;\u53d1\u9001\u961f\u5217\u6ca1\u6709\u4e0a\u9650<\/h3>\n<p>\u540e\u679c&#xff1a;\u6162\u5ba2\u6237\u7aef\u53ef\u4ee5\u4f7f\u8fdb\u7a0b\u5185\u5b58\u6301\u7eed\u589e\u957f\u3002<\/p>\n<h3>\u56db\u5341\u4e94\u3001\u9519\u8bef&#xff1a;ET \u8bbe\u7f6e\u5904\u7406\u9884\u7b97\u4f46\u4e0d\u91cd\u65b0\u6fc0\u6d3b<\/h3>\n<p>\u540e\u679c&#xff1a;\u9884\u7b97\u8017\u5c3d\u65f6\u7f13\u51b2\u533a\u53ef\u80fd\u4ecd\u7136\u53ef\u8bfb&#xff0c;\u4f46\u6ca1\u6709\u65b0\u8fb9\u7f18\u89e6\u53d1\u3002<\/p>\n<h3>\u56db\u5341\u516d\u3001\u9519\u8bef&#xff1a;EPOLLRDHUP \u7acb\u5373 close<\/h3>\n<p>\u540e\u679c&#xff1a;\u53ef\u80fd\u4e22\u5f03 FIN \u4e4b\u524d\u5df2\u7ecf\u5230\u8fbe\u4f46\u5c1a\u672a\u8bfb\u53d6\u7684\u6570\u636e&#xff0c;\u6216\u4e22\u5f03\u5c1a\u672a\u53d1\u9001\u7684\u54cd\u5e94\u3002<\/p>\n<h3>\u56db\u5341\u4e03\u3001\u9519\u8bef&#xff1a;\u5728 epoll_event.data.ptr \u4e2d\u4fdd\u5b58\u88f8\u6307\u9488\u5374\u4e0d\u7ba1\u7406\u751f\u547d\u5468\u671f<\/h3>\n<p>\u5982\u679c\u8fde\u63a5\u5bf9\u8c61\u88ab\u91ca\u653e&#xff0c;\u800c ready event \u4e2d\u4ecd\u4fdd\u7559\u65e7\u6307\u9488&#xff0c;\u5c31\u53ef\u80fd\u51fa\u73b0 use-after-free\u3002<\/p>\n<p>\u672c\u6587\u4f7f\u7528 data.fd \u548c unordered_map&lt;int, ClientState&gt;&#xff0c;\u964d\u4f4e\u4e86\u793a\u4f8b\u4e2d\u7684\u751f\u547d\u5468\u671f\u590d\u6742\u5ea6\u3002\u751f\u4ea7\u4ee3\u7801\u53ef\u4ee5\u4f7f\u7528\u6307\u9488&#xff0c;\u4f46\u5fc5\u987b\u7ed3\u5408&#xff1a;<\/p>\n<ul>\n<li>\u7a33\u5b9a\u5bf9\u8c61\u5730\u5740&#xff1b;<\/li>\n<li>\u5f15\u7528\u8ba1\u6570&#xff1b;<\/li>\n<li>generation \u6807\u8bc6&#xff1b;<\/li>\n<li>\u5ef6\u8fdf\u9500\u6bc1&#xff1b;<\/li>\n<li>\u7ebf\u7a0b\u540c\u6b65\u3002<\/li>\n<\/ul>\n<hr \/>\n<h2>\u7b2c\u4e8c\u5341\u4e00\u90e8\u5206&#xff1a;\u8fdb\u4e00\u6b65\u5de5\u7a0b\u5316\u65b9\u5411<\/h2>\n<h3>\u56db\u5341\u516b\u3001\u5e94\u7528\u5c42\u534f\u8bae\u62c6\u5305<\/h3>\n<p>Echo \u793a\u4f8b\u628a\u6536\u5230\u7684\u5b57\u8282\u539f\u6837\u8fd4\u56de&#xff0c;\u4e0d\u4ee3\u8868\u4e00\u6b21 recv() \u5c31\u662f\u4e00\u6761\u4e1a\u52a1\u6d88\u606f\u3002<\/p>\n<p>\u751f\u4ea7\u670d\u52a1\u901a\u5e38\u9700\u8981&#xff1a;<\/p>\n<ul>\n<li>\u56fa\u5b9a\u957f\u5ea6\u534f\u8bae&#xff1b;<\/li>\n<li>\u5206\u9694\u7b26\u534f\u8bae&#xff1b;<\/li>\n<li>\u957f\u5ea6\u5b57\u6bb5 &#043; Payload&#xff1b;<\/li>\n<li>HTTP\/WebSocket \u7b49\u6210\u719f\u534f\u8bae\u89e3\u6790\u5668\u3002<\/li>\n<\/ul>\n<p>\u957f\u5ea6\u5934\u793a\u610f&#xff1a;<\/p>\n<p>\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510<br \/>\n\u2502 4 \u5b57\u8282\u957f\u5ea6 N \u2502 N \u5b57\u8282 Payload      \u2502<br \/>\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518<\/p>\n<p>\u6bcf\u8fde\u63a5\u9700\u8981\u72ec\u7acb\u63a5\u6536\u7f13\u51b2\u533a&#xff1a;<\/p>\n<p><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">ClientState<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string input<span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string output<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u89e3\u6790\u539f\u5219&#xff1a;<\/p>\n<p>input \u4e0d\u591f\u4e00\u5e27&#xff1a;<br \/>\n    \u4fdd\u7559&#xff0c;\u7b49\u5f85\u4e0b\u6b21 recv<\/p>\n<p>input \u5305\u542b\u5b8c\u6574\u4e00\u5e27&#xff1a;<br \/>\n    \u53d6\u51fa\u5e76\u5904\u7406<\/p>\n<p>input \u5305\u542b\u591a\u5e27&#xff1a;<br \/>\n    \u5faa\u73af\u89e3\u6790<\/p>\n<h3>\u56db\u5341\u4e5d\u3001\u5b9a\u65f6\u5668<\/h3>\n<p>\u53ef\u4ee5\u4f7f\u7528&#xff1a;<\/p>\n<ul>\n<li>timerfd&#xff1b;<\/li>\n<li>\u65f6\u95f4\u8f6e&#xff1b;<\/li>\n<li>\u6700\u5c0f\u5806&#xff1b;<\/li>\n<li>\u5468\u671f\u6027 epoll_wait \u8d85\u65f6\u3002<\/li>\n<\/ul>\n<p>\u7528\u4e8e\u5904\u7406&#xff1a;<\/p>\n<ul>\n<li>\u7a7a\u95f2\u8fde\u63a5\u8d85\u65f6&#xff1b;<\/li>\n<li>\u63e1\u624b\u8d85\u65f6&#xff1b;<\/li>\n<li>\u8bf7\u6c42\u5904\u7406\u8d85\u65f6&#xff1b;<\/li>\n<li>\u5fc3\u8df3\u3002<\/li>\n<\/ul>\n<h3>\u4e94\u5341\u3001\u4fe1\u53f7<\/h3>\n<p>\u53ef\u4ee5\u4f7f\u7528 signalfd \u628a\u4fe1\u53f7\u4e5f\u53d8\u6210 epoll \u4e8b\u4ef6&#xff0c;\u907f\u514d\u4f20\u7edf\u5f02\u6b65\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u4e2d\u7684\u9650\u5236\u3002<\/p>\n<h3>\u4e94\u5341\u4e00\u3001\u591a\u7ebf\u7a0b<\/h3>\n<p>\u5e38\u89c1\u6a21\u578b\u5305\u62ec&#xff1a;<\/p>\n<p>\u5355 acceptor &#043; \u591a event loop<br \/>\n\u6bcf\u7ebf\u7a0b\u4e00\u4e2a epoll<br \/>\n\u4e3b\u4ece Reactor<br \/>\nEPOLLONESHOT &#043; \u5de5\u4f5c\u7ebf\u7a0b<br \/>\nSO_REUSEPORT \u591a\u76d1\u542c\u5b9e\u4f8b<\/p>\n<p>\u591a\u7ebf\u7a0b\u4e0b\u8981\u989d\u5916\u89e3\u51b3&#xff1a;<\/p>\n<ul>\n<li>\u8fde\u63a5\u5f52\u5c5e&#xff1b;<\/li>\n<li>\u540c\u4e00 fd \u662f\u5426\u4f1a\u5e76\u53d1\u5904\u7406&#xff1b;<\/li>\n<li>\u5bf9\u8c61\u9500\u6bc1\u65f6\u673a&#xff1b;<\/li>\n<li>\u8de8\u7ebf\u7a0b\u5524\u9192&#xff1b;<\/li>\n<li>\u53d1\u9001\u961f\u5217\u9501&#xff1b;<\/li>\n<li>fd \u590d\u7528&#xff1b;<\/li>\n<li>\u60ca\u7fa4\u3002<\/li>\n<\/ul>\n<h3>\u4e94\u5341\u4e8c\u3001\u8de8\u7ebf\u7a0b\u5524\u9192<\/h3>\n<p>\u5e38\u4f7f\u7528&#xff1a;<\/p>\n<ul>\n<li>eventfd&#xff1b;<\/li>\n<li>pipe&#xff1b;<\/li>\n<li>socketpair\u3002<\/li>\n<\/ul>\n<p>\u5de5\u4f5c\u7ebf\u7a0b\u5411 event loop \u63d0\u4ea4\u4efb\u52a1\u540e&#xff0c;\u901a\u8fc7 eventfd \u5524\u9192 epoll_wait()\u3002<\/p>\n<hr \/>\n<h2>\u7b2c\u4e8c\u5341\u4e8c\u90e8\u5206&#xff1a;FAQ<\/h2>\n<h3>\u4e94\u5341\u4e09\u3001close \u524d\u5fc5\u987b EPOLL_CTL_DEL \u5417<\/h3>\n<p>\u7b80\u5355\u5355\u7ebf\u7a0b\u7a0b\u5e8f\u4e2d&#xff0c;\u5173\u95ed\u6587\u4ef6\u63cf\u8ff0\u7b26\u7684\u6700\u7ec8\u5f15\u7528\u540e&#xff0c;\u5185\u6838\u4f1a\u6e05\u7406\u76f8\u5173 epoll \u76d1\u63a7\u5173\u7cfb\u3002<\/p>\n<p>\u4f46\u663e\u5f0f DEL \u4ecd\u6709\u4ef7\u503c&#xff1a;<\/p>\n<ul>\n<li>\u7528\u6237\u6001\u751f\u547d\u5468\u671f\u6e05\u6670&#xff1b;<\/li>\n<li>\u9519\u8bef\u66f4\u5bb9\u6613\u5b9a\u4f4d&#xff1b;<\/li>\n<li>\u590d\u6742\u7684 dup()\/\u5171\u4eab open file description \u573a\u666f\u4e2d\u66f4\u5bb9\u6613\u63a7\u5236&#xff1b;<\/li>\n<li>\u907f\u514d\u8fde\u63a5\u72b6\u6001\u5bb9\u5668\u548c epoll \u5174\u8da3\u96c6\u5408\u957f\u65f6\u95f4\u4e0d\u4e00\u81f4\u3002<\/li>\n<\/ul>\n<p>\u4e0d\u80fd\u7b80\u5355\u603b\u7ed3\u6210\u201cclose \u4e00\u5b9a\u4f1a\u4ea7\u751f\u5e7d\u7075\u4e8b\u4ef6\u201d\u6216\u201cDEL \u6c38\u8fdc\u5fc5\u987b\u201d\u3002<\/p>\n<h3>\u4e94\u5341\u56db\u3001accepted socket \u4f1a\u7ee7\u627f O_NONBLOCK \u5417<\/h3>\n<p>\u5728 Linux \u4e0a&#xff0c;accept() \u8fd4\u56de\u7684\u65b0\u5957\u63a5\u5b57\u4e0d\u4f1a\u81ea\u52a8\u7ee7\u627f\u76d1\u542c\u5957\u63a5\u5b57\u7684 O_NONBLOCK \u6587\u4ef6\u72b6\u6001\u6807\u5fd7\u3002<\/p>\n<p>\u56e0\u6b64\u9700\u8981&#xff1a;<\/p>\n<p><span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">,<\/span> F_SETFL<span class=\"token punctuation\">,<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span> <span class=\"token operator\">|<\/span> O_NONBLOCK<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u6216\u8005&#xff1a;<\/p>\n<p><span class=\"token function\">accept4<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">,<\/span> SOCK_NONBLOCK <span class=\"token operator\">|<\/span> SOCK_CLOEXEC<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<h3>\u4e94\u5341\u4e94\u3001EAGAIN \u548c EWOULDBLOCK \u662f\u5426\u76f8\u540c<\/h3>\n<p>Linux \u4e0a\u901a\u5e38\u76f8\u540c&#xff0c;\u4f46\u53ef\u79fb\u690d\u4ee3\u7801\u5e94\u540c\u65f6\u68c0\u67e5&#xff1a;<\/p>\n<p>errno <span class=\"token operator\">&#061;&#061;<\/span> EAGAIN <span class=\"token operator\">||<\/span><br \/>\nerrno <span class=\"token operator\">&#061;&#061;<\/span> EWOULDBLOCK<\/p>\n<h3>\u4e94\u5341\u516d\u3001LT \u53ef\u4ee5\u4f7f\u7528\u963b\u585e\u5957\u63a5\u5b57\u5417<\/h3>\n<p>\u4ece\u63a5\u53e3\u8bed\u4e49\u4e0a\u53ef\u4ee5&#xff0c;\u4f46\u4e8b\u4ef6\u9a71\u52a8\u670d\u52a1\u5668\u901a\u5e38\u4ecd\u5efa\u8bae\u4f7f\u7528\u975e\u963b\u585e\u5957\u63a5\u5b57&#xff0c;\u4ee5\u4fdd\u8bc1\u4efb\u4f55 I\/O \u64cd\u4f5c\u90fd\u4e0d\u4f1a\u610f\u5916\u957f\u65f6\u95f4\u963b\u585e\u6574\u4e2a\u4e8b\u4ef6\u5faa\u73af\u3002<\/p>\n<h3>\u4e94\u5341\u4e03\u3001ET \u662f\u5426\u6bcf\u6b21\u90fd\u5fc5\u987b\u8bfb\u5230 EAGAIN<\/h3>\n<p>\u6700\u7a33\u5b9a\u3001\u6700\u5bb9\u6613\u9a8c\u8bc1\u7684\u901a\u7528\u89c4\u5219\u662f&#xff1a;<\/p>\n<p>\u975e\u963b\u585e\u8bfb\u53d6\u5230 EAGAIN<\/p>\n<p>\u5bf9\u6d41\u5f0f fd&#xff0c;\u67d0\u4e9b\u60c5\u51b5\u4e0b\u77ed\u8bfb\u4e5f\u53ef\u4ee5\u8bf4\u660e\u5f53\u524d\u6570\u636e\u5df2\u7ecf\u53d6\u5c3d&#xff0c;\u4f46\u628a\u6240\u6709 ET \u8def\u5f84\u7edf\u4e00\u5199\u6210\u201c\u5faa\u73af\u5230 EAGAIN\u201d\u66f4\u4e0d\u5bb9\u6613\u51fa\u9519\u3002<\/p>\n<p>\u5982\u679c\u4e3a\u4e86\u516c\u5e73\u9884\u7b97\u63d0\u524d\u505c\u6b62&#xff0c;\u5c31\u5fc5\u987b\u4f7f\u7528\u7528\u6237\u6001\u91cd\u65b0\u8c03\u5ea6\u6216 EPOLLONESHOT \u91cd\u88c5\u7b49\u673a\u5236&#xff0c;\u4e0d\u80fd\u76f4\u63a5\u56de\u5230\u666e\u901a epoll_wait() \u540e\u5047\u8bbe\u4e00\u5b9a\u4f1a\u6709\u65b0\u8fb9\u7f18\u3002<\/p>\n<h3>\u4e94\u5341\u516b\u3001epoll \u53ef\u4ee5\u76d1\u63a7\u666e\u901a\u6587\u4ef6\u5417<\/h3>\n<p>\u5e38\u89c4\u78c1\u76d8\u6587\u4ef6\u901a\u5e38\u4e0d\u9002\u5408\u901a\u8fc7 epoll \u83b7\u53d6\u5c31\u7eea\u901a\u77e5&#xff0c;epoll_ctl() \u53ef\u80fd\u8fd4\u56de EPERM\u3002epoll \u4e3b\u8981\u9762\u5411\u652f\u6301\u8f6e\u8be2\u8bed\u4e49\u7684\u5bf9\u8c61&#xff0c;\u4f8b\u5982 socket\u3001pipe\u3001eventfd\u3001timerfd\u3001signalfd \u7b49\u3002<\/p>\n<h3>\u4e94\u5341\u4e5d\u3001epoll \u80fd\u66ff\u4ee3\u7ebf\u7a0b\u6c60\u5417<\/h3>\n<p>\u4e0d\u80fd\u3002<\/p>\n<p>epoll \u89e3\u51b3\u7684\u662f&#xff1a;<\/p>\n<p>\u5927\u91cf I\/O \u5bf9\u8c61\u7684\u5c31\u7eea\u7b49\u5f85<\/p>\n<p>\u7ebf\u7a0b\u6c60\u89e3\u51b3\u7684\u662f&#xff1a;<\/p>\n<p>CPU \u5bc6\u96c6\u578b\u6216\u53ef\u80fd\u963b\u585e\u7684\u4e1a\u52a1\u4efb\u52a1\u5e76\u53d1\u6267\u884c<\/p>\n<p>\u4e24\u8005\u7ecf\u5e38\u7ec4\u5408\u4f7f\u7528\u3002<\/p>\n<hr \/>\n<h2>\u7b2c\u4e8c\u5341\u4e09\u90e8\u5206&#xff1a;\u516d\u5c42\u6f14\u8fdb\u603b\u7ed3<\/h2>\n<h3>\u516d\u5341\u3001\u6bcf\u4e00\u5c42\u5230\u5e95\u5b66\u5230\u4e86\u4ec0\u4e48<\/h3>\n<h4>\u7b2c 0 \u5c42&#xff1a;select<\/h4>\n<p>\u7406\u89e3&#xff1a;<\/p>\n<ul>\n<li>fd \u96c6\u5408&#xff1b;<\/li>\n<li>select() \u7834\u574f\u6027\u4fee\u6539&#xff1b;<\/li>\n<li>\u5168\u91cf\u626b\u63cf&#xff1b;<\/li>\n<li>FD_SETSIZE\u3002<\/li>\n<\/ul>\n<h4>\u7b2c 1 \u5c42&#xff1a;epoll LT \u6700\u5c0f\u8fc1\u79fb<\/h4>\n<p>\u7406\u89e3&#xff1a;<\/p>\n<ul>\n<li>epoll \u5b9e\u4f8b&#xff1b;<\/li>\n<li>interest list&#xff1b;<\/li>\n<li>ready events&#xff1b;<\/li>\n<li>epoll_create1\/ctl\/wait\u3002<\/li>\n<\/ul>\n<h4>\u7b2c 2 \u5c42&#xff1a;\u975e\u963b\u585e LT<\/h4>\n<p>\u7406\u89e3&#xff1a;<\/p>\n<ul>\n<li>\u975e\u963b\u585e\u5957\u63a5\u5b57&#xff1b;<\/li>\n<li>EINTR&#xff1b;<\/li>\n<li>EAGAIN&#xff1b;<\/li>\n<li>\u6392\u7a7a\u8fde\u63a5\u961f\u5217&#xff1b;<\/li>\n<li>LT \u4e5f\u5e94\u907f\u514d\u963b\u585e\u4e8b\u4ef6\u5faa\u73af\u3002<\/li>\n<\/ul>\n<h4>\u7b2c 3 \u5c42&#xff1a;ET \u6b63\u786e\u8bfb\u53d6<\/h4>\n<p>\u7406\u89e3&#xff1a;<\/p>\n<ul>\n<li>EPOLLET&#xff1b;<\/li>\n<li>\u5355\u6b21 read \u7684\u505c\u6ede\u95ee\u9898&#xff1b;<\/li>\n<li>\u963b\u585e\u5faa\u73af\u8bfb\u7684\u4e8b\u4ef6\u5faa\u73af\u5361\u987f&#xff1b;<\/li>\n<li>\u975e\u963b\u585e &#043; \u5904\u7406\u5230 EAGAIN\u3002<\/li>\n<\/ul>\n<h4>\u7b2c 4 \u5c42&#xff1a;\u5199\u4e8b\u4ef6\u72b6\u6001\u673a<\/h4>\n<p>\u7406\u89e3&#xff1a;<\/p>\n<ul>\n<li>\u90e8\u5206\u53d1\u9001&#xff1b;<\/li>\n<li>\u53d1\u9001\u504f\u79fb&#xff1b;<\/li>\n<li>EPOLLOUT \u6309\u9700\u8ba2\u9605&#xff1b;<\/li>\n<li>\u534a\u5173\u95ed&#xff1b;<\/li>\n<li>MSG_NOSIGNAL\u3002<\/li>\n<\/ul>\n<h4>\u7b2c 5 \u5c42&#xff1a;\u5de5\u7a0b\u8fb9\u754c<\/h4>\n<p>\u7406\u89e3&#xff1a;<\/p>\n<ul>\n<li>\u80cc\u538b&#xff1b;<\/li>\n<li>\u9ad8\u4f4e\u6c34\u4f4d&#xff1b;<\/li>\n<li>\u5185\u5b58\u786c\u4e0a\u9650&#xff1b;<\/li>\n<li>\u6bcf\u4e8b\u4ef6\u9884\u7b97&#xff1b;<\/li>\n<li>EPOLLONESHOT&#xff1b;<\/li>\n<li>\u516c\u5e73\u6027\u3002<\/li>\n<\/ul>\n<h3>\u516d\u5341\u4e00\u3001\u6700\u7ec8\u6838\u5fc3\u539f\u5219<\/h3>\n<p>\u53ef\u4ee5\u628a\u6574\u7bc7\u6587\u7ae0\u538b\u7f29\u6210\u516d\u53e5\u8bdd&#xff1a;<\/p>\n<p>1. epoll \u53ea\u62a5\u544a\u5c31\u7eea&#xff0c;\u4e0d\u66ff\u4f60\u6267\u884c I\/O\u3002<br \/>\n2. \u975e\u963b\u585e I\/O \u7684 EAGAIN \u662f\u6b63\u5e38\u8fb9\u754c&#xff0c;\u4e0d\u662f\u9519\u8bef\u3002<br \/>\n3. ET \u6536\u5230\u4e8b\u4ef6\u540e&#xff0c;\u8981\u628a\u5f53\u524d\u5c31\u7eea\u72b6\u6001\u5904\u7406\u5b8c\u6574\u3002<br \/>\n4. TCP send \u53ef\u80fd\u90e8\u5206\u5b8c\u6210&#xff0c;\u5fc5\u987b\u4fdd\u5b58\u53d1\u9001\u72b6\u6001\u3002<br \/>\n5. EPOLLOUT \u53ea\u5728\u5b58\u5728\u5f85\u53d1\u9001\u6570\u636e\u65f6\u76d1\u542c\u3002<br \/>\n6. \u6ca1\u6709\u80cc\u538b\u548c\u8d44\u6e90\u4e0a\u9650\u7684\u53d1\u9001\u961f\u5217\u4e0d\u662f\u5b8c\u6574\u8bbe\u8ba1\u3002<\/p>\n<hr \/>\n<h2>\u9644\u5f55 A&#xff1a;\u6e90\u7801\u76ee\u5f55<\/h2>\n<p>epoll_\u5206\u5c42\u5347\u7ea7\u6280\u672f\u535a\u5ba2\/<br \/>\n\u251c\u2500\u2500 00_select_original\/<br \/>\n\u2502   \u251c\u2500\u2500 server.cpp<br \/>\n\u2502   \u2514\u2500\u2500 client.cpp<br \/>\n\u251c\u2500\u2500 01_epoll_lt_minimal\/<br \/>\n\u2502   \u251c\u2500\u2500 server.cpp<br \/>\n\u2502   \u2514\u2500\u2500 client.cpp<br \/>\n\u251c\u2500\u2500 02_epoll_lt_nonblocking\/<br \/>\n\u2502   \u251c\u2500\u2500 server.cpp<br \/>\n\u2502   \u2514\u2500\u2500 client.cpp<br \/>\n\u251c\u2500\u2500 03_epoll_et_correct_read\/<br \/>\n\u2502   \u251c\u2500\u2500 server.cpp<br \/>\n\u2502   \u2514\u2500\u2500 client.cpp<br \/>\n\u251c\u2500\u2500 04_epoll_et_write_queue\/<br \/>\n\u2502   \u251c\u2500\u2500 server.cpp<br \/>\n\u2502   \u2514\u2500\u2500 client.cpp<br \/>\n\u251c\u2500\u2500 05_epoll_et_backpressure\/<br \/>\n\u2502   \u251c\u2500\u2500 server.cpp<br \/>\n\u2502   \u2514\u2500\u2500 client.cpp<br \/>\n\u251c\u2500\u2500 pitfalls\/<br \/>\n\u2502   \u251c\u2500\u2500 et_single_read_server.cpp<br \/>\n\u2502   \u2514\u2500\u2500 et_blocking_loop_server.cpp<br \/>\n\u251c\u2500\u2500 tools\/<br \/>\n\u2502   \u2514\u2500\u2500 stress_client.cpp<br \/>\n\u251c\u2500\u2500 Makefile<br \/>\n\u251c\u2500\u2500 README.md<br \/>\n\u2514\u2500\u2500 \u4ece_select_\u5230_epoll_C&#043;&#043;17_\u5b8c\u6574\u6280\u672f\u535a\u5ba2.md<\/p>\n<h2>\u9644\u5f55 B&#xff1a;\u5b98\u65b9\u8d44\u6599\u540d\u79f0<\/h2>\n<p>\u8fdb\u4e00\u6b65\u6838\u5bf9\u63a5\u53e3\u8bed\u4e49\u65f6&#xff0c;\u5e94\u4f18\u5148\u67e5\u9605 Linux man-pages \u4e2d\u7684&#xff1a;<\/p>\n<ul>\n<li>epoll(7)<\/li>\n<li>epoll_create(2)<\/li>\n<li>epoll_ctl(2)<\/li>\n<li>epoll_wait(2)<\/li>\n<li>accept(2)<\/li>\n<li>recv(2)<\/li>\n<li>send(2)<\/li>\n<li>socket(7)<\/li>\n<li>fcntl(2)<\/li>\n<\/ul>\n<hr \/>\n<p>\u672c\u6587\u7684\u91cd\u70b9\u4e0d\u662f\u8bb0\u4f4f\u67d0\u4efd\u6700\u7ec8\u4ee3\u7801&#xff0c;\u800c\u662f\u5efa\u7acb\u53ef\u4ee5\u8fc1\u79fb\u5230\u771f\u5b9e\u7f51\u7edc\u9879\u76ee\u7684\u72b6\u6001\u673a\u601d\u7ef4&#xff1a;<\/p>\n<p>\u6bcf\u4e2a\u8fde\u63a5\u90fd\u4e0d\u662f\u4e00\u4e2a\u201cfd \u6570\u5b57\u201d&#xff0c;\u800c\u662f\u4e00\u4e2a\u6301\u7eed\u53d8\u5316\u7684 I\/O \u72b6\u6001\u5bf9\u8c61&#xff1b;epoll \u53ea\u662f\u8ba9\u8fd9\u4e9b\u72b6\u6001\u5bf9\u8c61\u5728\u5408\u9002\u7684\u65f6\u673a\u83b7\u5f97\u5904\u7406\u673a\u4f1a\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u6587\u7ae0\u76ee\u5f55\u4ece select \u5230 epoll&#xff1a;C17 TCP \u670d\u52a1\u5668\u7684\u516d\u5c42\u6e10\u8fdb\u5f0f\u91cd\u6784\u4e00\u3001\u4e3a\u4ec0\u4e48\u8981\u91c7\u7528\u201c\u5206\u5c42\u5347\u7ea7\u201d\u4e8c\u3001\u5148\u5efa\u7acb\u6b63\u786e\u7684 epoll \u5fc3\u667a\u6a21\u578b2.1 epoll \u4e0d\u662f\u5f02\u6b65 I\/O2.2 interest list \u4e0e ready list2.3 epoll \u5e76\u4e0d\u662f\u201c\u5b8c\u5168\u96f6\u62f7\u8d1d\u201d2.4 \u4e0d\u8981\u628a epoll \u7684\u590d\u6742\u5ea6\u6982\u62ec\u6210\u201c\u6240\u6709\u64cd\u4f5c\u90fd\u662f O(1)\u201d\u7b2c\u4e00\u90e8\u5206&#xff1a;\u7b2c 0 \u5c42\u2014\u2014\u539f\u59cb select \u7248\u672c\u4e09\u3001\u7b2c 0 \u5c42\u7684\u76ee\u76843.1 \u5b8c\u6574\u670d\u52a1\u7aef&#xff1a;<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[55,205,43],"topic":[],"class_list":["post-81405","post","type-post","status-publish","format-standard","hentry","category-server","tag-c","tag-tcp-ip","tag-43"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v20.3 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>11.\u5347\u7ea7\u7b80\u5355\u7684Epoll,\u4ece select \u5230 epoll\uff1aC++17 TCP \u670d\u52a1\u5668\u7684\u516d\u5c42\u6e10\u8fdb\u5f0f\u91cd\u6784 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.wsisp.com\/helps\/81405.html\" \/>\n<meta property=\"og:locale\" content=\"zh_CN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"11.\u5347\u7ea7\u7b80\u5355\u7684Epoll,\u4ece select \u5230 epoll\uff1aC++17 TCP \u670d\u52a1\u5668\u7684\u516d\u5c42\u6e10\u8fdb\u5f0f\u91cd\u6784 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"og:description\" content=\"\u6587\u7ae0\u76ee\u5f55\u4ece select \u5230 epoll&#xff1a;C17 TCP \u670d\u52a1\u5668\u7684\u516d\u5c42\u6e10\u8fdb\u5f0f\u91cd\u6784\u4e00\u3001\u4e3a\u4ec0\u4e48\u8981\u91c7\u7528\u201c\u5206\u5c42\u5347\u7ea7\u201d\u4e8c\u3001\u5148\u5efa\u7acb\u6b63\u786e\u7684 epoll \u5fc3\u667a\u6a21\u578b2.1 epoll \u4e0d\u662f\u5f02\u6b65 I\/O2.2 interest list \u4e0e ready list2.3 epoll \u5e76\u4e0d\u662f\u201c\u5b8c\u5168\u96f6\u62f7\u8d1d\u201d2.4 \u4e0d\u8981\u628a epoll \u7684\u590d\u6742\u5ea6\u6982\u62ec\u6210\u201c\u6240\u6709\u64cd\u4f5c\u90fd\u662f O(1)\u201d\u7b2c\u4e00\u90e8\u5206&#xff1a;\u7b2c 0 \u5c42\u2014\u2014\u539f\u59cb select \u7248\u672c\u4e09\u3001\u7b2c 0 \u5c42\u7684\u76ee\u76843.1 \u5b8c\u6574\u670d\u52a1\u7aef&#xff1a;\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.wsisp.com\/helps\/81405.html\" \/>\n<meta property=\"og:site_name\" content=\"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"article:published_time\" content=\"2026-07-24T17:22:24+00:00\" \/>\n<meta name=\"author\" content=\"admin\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"\u4f5c\u8005\" \/>\n\t<meta name=\"twitter:data1\" content=\"admin\" \/>\n\t<meta name=\"twitter:label2\" content=\"\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4\" \/>\n\t<meta name=\"twitter:data2\" content=\"54 \u5206\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/81405.html\",\"url\":\"https:\/\/www.wsisp.com\/helps\/81405.html\",\"name\":\"11.\u5347\u7ea7\u7b80\u5355\u7684Epoll,\u4ece select \u5230 epoll\uff1aC++17 TCP \u670d\u52a1\u5668\u7684\u516d\u5c42\u6e10\u8fdb\u5f0f\u91cd\u6784 - 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\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.wsisp.com\/helps\/81405.html","og_locale":"zh_CN","og_type":"article","og_title":"11.\u5347\u7ea7\u7b80\u5355\u7684Epoll,\u4ece select \u5230 epoll\uff1aC++17 TCP \u670d\u52a1\u5668\u7684\u516d\u5c42\u6e10\u8fdb\u5f0f\u91cd\u6784 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","og_description":"\u6587\u7ae0\u76ee\u5f55\u4ece select \u5230 epoll&#xff1a;C17 TCP \u670d\u52a1\u5668\u7684\u516d\u5c42\u6e10\u8fdb\u5f0f\u91cd\u6784\u4e00\u3001\u4e3a\u4ec0\u4e48\u8981\u91c7\u7528\u201c\u5206\u5c42\u5347\u7ea7\u201d\u4e8c\u3001\u5148\u5efa\u7acb\u6b63\u786e\u7684 epoll \u5fc3\u667a\u6a21\u578b2.1 epoll \u4e0d\u662f\u5f02\u6b65 I\/O2.2 interest list \u4e0e ready list2.3 epoll \u5e76\u4e0d\u662f\u201c\u5b8c\u5168\u96f6\u62f7\u8d1d\u201d2.4 \u4e0d\u8981\u628a epoll \u7684\u590d\u6742\u5ea6\u6982\u62ec\u6210\u201c\u6240\u6709\u64cd\u4f5c\u90fd\u662f O(1)\u201d\u7b2c\u4e00\u90e8\u5206&#xff1a;\u7b2c 0 \u5c42\u2014\u2014\u539f\u59cb select \u7248\u672c\u4e09\u3001\u7b2c 0 \u5c42\u7684\u76ee\u76843.1 \u5b8c\u6574\u670d\u52a1\u7aef&#xff1a;","og_url":"https:\/\/www.wsisp.com\/helps\/81405.html","og_site_name":"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","article_published_time":"2026-07-24T17:22:24+00:00","author":"admin","twitter_card":"summary_large_image","twitter_misc":{"\u4f5c\u8005":"admin","\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4":"54 \u5206"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/www.wsisp.com\/helps\/81405.html","url":"https:\/\/www.wsisp.com\/helps\/81405.html","name":"11.\u5347\u7ea7\u7b80\u5355\u7684Epoll,\u4ece select \u5230 epoll\uff1aC++17 TCP \u670d\u52a1\u5668\u7684\u516d\u5c42\u6e10\u8fdb\u5f0f\u91cd\u6784 - 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