{"id":123019,"date":"2026-11-06T08:18:26","date_gmt":"2026-11-06T00:18:26","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/123019.html"},"modified":"2026-11-06T08:18:26","modified_gmt":"2026-11-06T00:18:26","slug":"linux%e7%bd%91%e7%bb%9c%e7%bc%96%e7%a8%8b%ef%bc%9a%e5%bd%bb%e5%ba%95%e7%90%86%e8%a7%a3io%e5%a4%9a%e8%b7%af%e5%a4%8d%e7%94%a8select%ef%bc%81%e4%bb%8efd_set%e4%bd%8d%e5%9b%be%e3%80%81%e8%af%bb%e5%86%99","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/123019.html","title":{"rendered":"Linux\u7f51\u7edc\u7f16\u7a0b\uff1a\u5f7b\u5e95\u7406\u89e3IO\u591a\u8def\u590d\u7528select\uff01\u4ecefd_set\u4f4d\u56fe\u3001\u8bfb\u5199\u5c31\u7eea\u5230\u624b\u5199TCP\u591a\u5ba2\u6237\u7aef\u5b57\u5178\u670d\u52a1\u5668"},"content":{"rendered":"<h2>Linux\u7f51\u7edc\u7f16\u7a0b&#xff1a;\u5f7b\u5e95\u7406\u89e3IO\u591a\u8def\u590d\u7528select&#xff01;\u4ecefd_set\u4f4d\u56fe\u3001\u8bfb\u5199\u5c31\u7eea\u5230\u624b\u5199TCP\u591a\u5ba2\u6237\u7aef\u5b57\u5178\u670d\u52a1\u5668<\/h2>\n<p><img decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/11\/20261106001814-6aed1cc6db5f3.png\" alt=\"\u5934\u50cf\" \/><\/p>\n<p> <font color=\"#FF4D4F\" size=\"4\"><b>&#x1f525; \u661f\u6052\u968f\u98ce&#xff1a;<\/b><\/font><br \/>\n <font color=\"#FF4D4F\" size=\"4\"><b>\u4e2a\u4eba\u4e3b\u9875<\/b><\/font><\/p>\n<p> <font color=\"#66CCFF\" size=\"3\"><b>\u2744\ufe0f \u4e2a\u4eba\u4e13\u680f&#xff1a;<\/b><\/font><br \/>\n <font color=\"#66CCFF\" size=\"3\"><b>\u300aLinux\u7f51\u7edc\u7f16\u7a0b\u4ece0\u52301\u300b<\/b><\/font><br \/>\n <font color=\"#333333\" size=\"3\"><b>&#xff5c;<\/b><\/font><br \/>\n <font color=\"#66CCFF\" size=\"3\"><b>\u300aC\u8bed\u8a00\u57fa\u7840\u300b<\/b><\/font><br \/>\n <font color=\"#333333\" size=\"3\"><b>&#xff5c;<\/b><\/font><br \/>\n <font color=\"#66CCFF\" size=\"3\"><b>\u300a\u6570\u636e\u7ed3\u6784\u300b<\/b><\/font><br \/>\n <font color=\"#333333\" size=\"3\"><b>&#xff5c;<\/b><\/font><br \/>\n <font color=\"#66CCFF\" size=\"3\"><b>\u300a\u673a\u5668\u5b66\u4e60\u5bfc\u8bba\u300b<\/b><\/font><br \/>\n <font color=\"#333333\" size=\"3\"><b>&#xff5c;<\/b><\/font><br \/>\n <font color=\"#66CCFF\" size=\"3\"><b>\u300a\u524d\u7aef\u57fa\u7840\u300b<\/b><\/font><br \/>\n <font color=\"#333333\" size=\"3\"><b>&#xff5c;<\/b><\/font><br \/>\n <font color=\"#66CCFF\" size=\"3\"><b>\u300apython\u57fa\u7840\u300b<\/b><\/font><br \/>\n <font color=\"#333333\" size=\"3\"><b>&#xff5c;<\/b><\/font><br \/>\n <font color=\"#66CCFF\" size=\"3\"><b>\u300aC&#043;&#043;\u4ece\u5165\u95e8\u5230\u5165\u571f\u300b<\/b><\/font><br \/>\n <font color=\"#333333\" size=\"3\"><b>&#xff5c;<\/b><\/font><br \/>\n <font color=\"#66CCFF\" size=\"3\"><b>\u300aLinux\u7684\u5b66\u4e60\u4e4b\u65c5\u300b<\/b><\/font> <\/p>\n<p> <font color=\"#F5B400\" size=\"5\"><b>\u2728 \u6570\u636e\u5373\u77e5\u8bc6&#xff0c;\u538b\u7f29\u5373\u667a\u80fd<\/b><\/font><\/p>\n<hr \/>\n<h4>\u6587\u7ae0\u76ee\u5f55<\/h4>\n<ul>\n<li>Linux\u7f51\u7edc\u7f16\u7a0b&#xff1a;\u5f7b\u5e95\u7406\u89e3IO\u591a\u8def\u590d\u7528select&#xff01;\u4ecefd_set\u4f4d\u56fe\u3001\u8bfb\u5199\u5c31\u7eea\u5230\u624b\u5199TCP\u591a\u5ba2\u6237\u7aef\u5b57\u5178\u670d\u52a1\u5668<\/li>\n<li>\n<ul>\n<li>\u524d\u8a00&#xff1a;\u4e3a\u4ec0\u4e48\u6709\u4e86\u975e\u963b\u585eIO&#xff0c;\u8fd8\u9700\u8981select&#xff1f;<\/li>\n<\/ul>\n<\/li>\n<li>\u4e00\u3001\u4ec0\u4e48\u662fI\/O\u591a\u8def\u8f6c\u63a5&#xff1f;<\/li>\n<li>\n<ul>\n<li>1.1 \u666e\u901a\u963b\u585eI\/O\u7684\u95ee\u9898<\/li>\n<li>1.2 \u975e\u963b\u585e\u8f6e\u8be2\u7684\u6539\u8fdb\u4e0e\u95ee\u9898<\/li>\n<li>1.3 select\u7684\u89e3\u51b3\u65b9\u6848<\/li>\n<li>1.4 select\u662f\u4e0d\u662f\u5f02\u6b65I\/O&#xff1f;<\/li>\n<li>1.5 select\u4e00\u5b9a\u4e0d\u4f1a\u963b\u585e\u5417&#xff1f;<\/li>\n<\/ul>\n<\/li>\n<li>\u4e8c\u3001select\u51fd\u6570\u539f\u578b<\/li>\n<li>\u4e09\u3001\u7b2c\u4e00\u4e2a\u53c2\u6570nfds\u662f\u4ec0\u4e48\u610f\u601d&#xff1f;<\/li>\n<li>\n<ul>\n<li>3.1 \u4e3a\u4ec0\u4e48\u4e0d\u662f\u6587\u4ef6\u63cf\u8ff0\u7b26\u6570\u91cf&#xff1f;<\/li>\n<li>3.2 \u4e3a\u4ec0\u4e48\u8981\u52a01&#xff1f;<\/li>\n<li>3.3 \u53e6\u4e00\u4e2a\u4f8b\u5b50<\/li>\n<\/ul>\n<\/li>\n<li>\u56db\u3001readfds\u3001writefds\u3001exceptfds\u5206\u522b\u662f\u4ec0\u4e48&#xff1f;<\/li>\n<li>\n<ul>\n<li>4.1 readfds&#xff1a;\u8bfb\u5c31\u7eea\u96c6\u5408<\/li>\n<li>4.2 writefds&#xff1a;\u5199\u5c31\u7eea\u96c6\u5408<\/li>\n<li>4.3 exceptfds&#xff1a;\u5f02\u5e38\u6761\u4ef6\u96c6\u5408<\/li>\n<li>4.4 \u5982\u679c\u53ea\u9700\u8981\u76d1\u89c6\u8bfb\u4e8b\u4ef6\u600e\u4e48\u529e&#xff1f;<\/li>\n<\/ul>\n<\/li>\n<li>\u4e94\u3001\u7b2c\u4e94\u4e2a\u53c2\u6570timeout\u662f\u4ec0\u4e48\u610f\u601d&#xff1f;<\/li>\n<li>\n<ul>\n<li>5.1 timeval\u7ed3\u6784<\/li>\n<li>5.2 \u7b2c\u4e00\u79cd\u60c5\u51b5&#xff1a;timeout\u4e3aNULL<\/li>\n<li>5.3 \u7b2c\u4e8c\u79cd\u60c5\u51b5&#xff1a;timeout\u4e3a0<\/li>\n<li>5.4 \u7b2c\u4e09\u79cd\u60c5\u51b5&#xff1a;\u6307\u5b9a\u8d85\u65f6\u65f6\u95f4<\/li>\n<li>5.5 \u4e09\u79cd\u6a21\u5f0f\u603b\u7ed3<\/li>\n<\/ul>\n<\/li>\n<li>\u516d\u3001\u4ec0\u4e48\u662ffd_set&#xff1f;<\/li>\n<li>\n<ul>\n<li>6.1 fd_set\u53ef\u4ee5\u7406\u89e3\u4e3a\u4f4d\u56fe<\/li>\n<li>6.2 \u4e3a\u4ec0\u4e48\u4f7f\u7528\u4f4d\u56fe&#xff1f;<\/li>\n<li>6.3 fd_set\u662f\u4e0d\u662f\u4e00\u4e2a\u666e\u901a\u7684int\u6570\u7ec4&#xff1f;<\/li>\n<\/ul>\n<\/li>\n<li>\u4e03\u3001\u64cd\u4f5cfd_set\u7684\u56db\u4e2a\u91cd\u8981\u5b8f<\/li>\n<li>\n<ul>\n<li>7.1 FD_ZERO&#xff1a;\u6e05\u7a7a\u96c6\u5408<\/li>\n<li>7.2 FD_SET&#xff1a;\u6dfb\u52a0\u63cf\u8ff0\u7b26<\/li>\n<li>7.3 FD_CLR&#xff1a;\u5220\u9664\u63cf\u8ff0\u7b26<\/li>\n<li>7.4 FD_ISSET&#xff1a;\u68c0\u67e5\u63cf\u8ff0\u7b26\u662f\u5426\u5728\u96c6\u5408\u4e2d<\/li>\n<li>7.5 \u56db\u4e2a\u5b8f\u603b\u7ed3<\/li>\n<\/ul>\n<\/li>\n<li>\u516b\u3001\u901a\u8fc7\u4f4d\u56fe\u7406\u89e3select\u7684\u6267\u884c\u8fc7\u7a0b<\/li>\n<li>\n<ul>\n<li>8.1 \u7b2c\u4e00\u6b65&#xff1a;\u521b\u5efa\u5e76\u6e05\u7a7a\u96c6\u5408<\/li>\n<li>8.2 \u7b2c\u4e8c\u6b65&#xff1a;\u52a0\u5165fd5<\/li>\n<li>8.3 \u7b2c\u4e09\u6b65&#xff1a;\u52a0\u5165fd2\u548cfd1<\/li>\n<li>8.4 \u7b2c\u56db\u6b65&#xff1a;\u8c03\u7528select<\/li>\n<li>8.5 \u7b2c\u4e94\u6b65&#xff1a;\u5047\u8bbefd1\u548cfd2\u5c31\u7eea<\/li>\n<li>8.6 \u6700\u7ec8\u8fc7\u7a0b<\/li>\n<\/ul>\n<\/li>\n<li>\u4e5d\u3001select\u4f1a\u4fee\u6539fd_set&#xff1a;\u4e3a\u4ec0\u4e48\u8fd9\u662f\u4e00\u4e2a\u5927\u5751&#xff1f;<\/li>\n<li>\n<ul>\n<li>9.1 \u9519\u8bef\u5199\u6cd5<\/li>\n<li>9.2 \u6b63\u786e\u601d\u8def\u4e00&#xff1a;\u6bcf\u8f6e\u91cd\u65b0\u8bbe\u7f6e<\/li>\n<li>9.3 \u6b63\u786e\u601d\u8def\u4e8c&#xff1a;\u4fdd\u5b58\u4e3b\u96c6\u5408<\/li>\n<li>9.4 \u4e3a\u4ec0\u4e48\u8fd9\u4e2a\u8bbe\u8ba1\u5f88\u91cd\u8981&#xff1f;<\/li>\n<\/ul>\n<\/li>\n<li>\u5341\u3001select\u7684\u8fd4\u56de\u503c<\/li>\n<li>\n<ul>\n<li>10.1 \u8fd4\u56de\u6b63\u6570<\/li>\n<li>10.2 \u8fd4\u56de0<\/li>\n<li>10.3 \u8fd4\u56de-1<\/li>\n<li>10.4 \u4e3a\u4ec0\u4e48\u9700\u8981\u5904\u7406EINTR&#xff1f;<\/li>\n<\/ul>\n<\/li>\n<li>\u5341\u4e00\u3001Socket\u4ec0\u4e48\u65f6\u5019\u7b97\u8bfb\u5c31\u7eea&#xff1f;<\/li>\n<li>\n<ul>\n<li>11.1 \u7b2c\u4e00\u79cd&#xff1a;\u63a5\u6536\u7f13\u51b2\u533a\u4e2d\u6709\u53ef\u8bfb\u53d6\u6570\u636e<\/li>\n<li>11.2 \u7b2c\u4e8c\u79cd&#xff1a;TCP\u5bf9\u7aef\u5173\u95ed\u8fde\u63a5<\/li>\n<li>11.3 \u7b2c\u4e09\u79cd&#xff1a;\u76d1\u542cSocket\u5b58\u5728\u5f85\u63a5\u53d7\u8fde\u63a5<\/li>\n<li>11.4 \u7b2c\u56db\u79cd&#xff1a;Socket\u5b58\u5728\u5f85\u5904\u7406\u9519\u8bef<\/li>\n<\/ul>\n<\/li>\n<li>\u5341\u4e8c\u3001Socket\u4ec0\u4e48\u65f6\u5019\u7b97\u5199\u5c31\u7eea&#xff1f;<\/li>\n<li>\n<ul>\n<li>12.1 \u53d1\u9001\u7f13\u51b2\u533a\u5177\u6709\u53ef\u7528\u7a7a\u95f4<\/li>\n<li>12.2 \u5199\u5c31\u7eea\u4e0d\u610f\u5473\u7740\u53ef\u4ee5\u4e00\u6b21\u5199\u5165\u4efb\u610f\u957f\u5ea6<\/li>\n<li>12.3 \u975e\u963b\u585econnect\u5b8c\u6210\u4ee5\u540e<\/li>\n<li>12.4 \u5173\u95ed\u5199\u65b9\u5411\u4e0e\u9519\u8bef\u60c5\u51b5<\/li>\n<\/ul>\n<\/li>\n<li>\u5341\u4e09\u3001\u5f02\u5e38\u5c31\u7eea\u662f\u4ec0\u4e48&#xff1f;<\/li>\n<li>\u5341\u56db\u3001select\u7684\u7279\u70b9<\/li>\n<li>\n<ul>\n<li>14.1 \u53ef\u4ee5\u540c\u65f6\u76d1\u89c6\u591a\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26<\/li>\n<li>14.2 select\u5bf9\u63cf\u8ff0\u7b26\u7f16\u53f7\u6709\u4e0a\u9650<\/li>\n<li>14.3 \u4e3a\u4ec0\u4e48\u8fd8\u9700\u8981\u4fdd\u5b58\u539f\u59cb\u63cf\u8ff0\u7b26\u96c6\u5408&#xff1f;<\/li>\n<li>14.4 \u4e3a\u4ec0\u4e48\u8fd8\u8981\u4fdd\u5b58maxfd&#xff1f;<\/li>\n<\/ul>\n<\/li>\n<li>\u5341\u4e94\u3001select\u7684\u7f3a\u70b9<\/li>\n<li>\n<ul>\n<li>15.1 \u7f3a\u70b9\u4e00&#xff1a;\u6bcf\u6b21\u90fd\u9700\u8981\u51c6\u5907\u63cf\u8ff0\u7b26\u96c6\u5408<\/li>\n<li>15.2 \u7f3a\u70b9\u4e8c&#xff1a;\u5b58\u5728\u7528\u6237\u6001\u4e0e\u5185\u6838\u6001\u7684\u6570\u636e\u590d\u5236<\/li>\n<li>15.3 \u7f3a\u70b9\u4e09&#xff1a;\u5185\u6838\u9700\u8981\u68c0\u67e5\u63cf\u8ff0\u7b26\u96c6\u5408<\/li>\n<li>15.4 \u7f3a\u70b9\u56db&#xff1a;\u5e94\u7528\u7a0b\u5e8f\u9700\u8981\u627e\u51fa\u5c31\u7eea\u63cf\u8ff0\u7b26<\/li>\n<li>15.5 \u7f3a\u70b9\u4e94&#xff1a;fd_set\u5b58\u5728\u5bb9\u91cf\u9650\u5236<\/li>\n<li>15.6 select\u3001poll\u3001epoll\u7684\u5b66\u4e60\u5173\u7cfb<\/li>\n<\/ul>\n<\/li>\n<li>\u5341\u516d\u3001\u7b2c\u4e00\u4e2a\u5b9e\u9a8c&#xff1a;\u4f7f\u7528select\u76d1\u542c\u6807\u51c6\u8f93\u5165<\/li>\n<li>\n<ul>\n<li>16.1 \u6574\u4e2a\u6587\u4ef6\u8981\u5b9e\u73b0\u4ec0\u4e48\u529f\u80fd&#xff1f;<\/li>\n<li>16.2 \u9700\u8981\u8bbe\u8ba1\u54ea\u4e9b\u63a5\u53e3&#xff1f;<\/li>\n<li>16.3 \u6807\u51c6\u8f93\u5165\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26<\/li>\n<\/ul>\n<\/li>\n<li>\u5341\u4e03\u3001\u6807\u51c6\u8f93\u5165\u5b9e\u9a8c\u5b8c\u6574\u4ee3\u7801<\/li>\n<li>\n<ul>\n<li>17.1 \u7f16\u8bd1<\/li>\n<li>17.2 \u8fd0\u884c<\/li>\n<li>17.3 \u4e3a\u4ec0\u4e48\u6bcf\u6b21\u5faa\u73af\u90fd\u8c03\u7528FD_ZERO&#xff1f;<\/li>\n<li>17.4 \u4e3a\u4ec0\u4e48\u6bcf\u8f6e\u90fd\u91cd\u65b0\u8bbe\u7f6etimeout&#xff1f;<\/li>\n<li>17.5 \u4e3a\u4ec0\u4e48\u9700\u8981fflush(stdout)&#xff1f;<\/li>\n<li>17.6 \u4e3a\u4ec0\u4e48read\u8fd4\u56de0\u8981\u9000\u51fa&#xff1f;<\/li>\n<li>17.7 \u6807\u51c6\u8f93\u5165\u5b9e\u9a8c\u8bf4\u660e\u4e86\u4ec0\u4e48&#xff1f;<\/li>\n<\/ul>\n<\/li>\n<li>\u5341\u516b\u3001\u7b2c\u4e8c\u4e2a\u5b9e\u9a8c&#xff1a;\u4f7f\u7528select\u5b9e\u73b0TCP\u5b57\u5178\u670d\u52a1\u5668<\/li>\n<li>\n<ul>\n<li>18.1 \u670d\u52a1\u5668\u9700\u8981\u5b9e\u73b0\u4ec0\u4e48\u529f\u80fd&#xff1f;<\/li>\n<li>18.3 \u76d1\u542cSocket\u4e0e\u901a\u4fe1Socket\u6709\u4ec0\u4e48\u533a\u522b&#xff1f;<\/li>\n<\/ul>\n<\/li>\n<li>\u5341\u4e5d\u3001\u5148\u8bbe\u8ba1\u670d\u52a1\u5668\u6587\u4ef6\u4e0e\u63a5\u53e3<\/li>\n<li>\n<ul>\n<li>19.1 \u4e3a\u4ec0\u4e48\u9700\u8981Selector\u7c7b&#xff1f;<\/li>\n<li>19.2 Selector\u9700\u8981\u63d0\u4f9b\u4ec0\u4e48\u63a5\u53e3&#xff1f;<\/li>\n<li>19.3 \u4e3a\u4ec0\u4e48Selector\u4e0d\u76f4\u63a5\u7ba1\u7406Socket\u751f\u547d\u5468\u671f&#xff1f;<\/li>\n<li>19.4 TcpSelectServer\u9700\u8981\u63d0\u4f9b\u4ec0\u4e48\u63a5\u53e3&#xff1f;<\/li>\n<li>19.5 Handler\u662f\u4ec0\u4e48&#xff1f;<\/li>\n<\/ul>\n<\/li>\n<li>\u4e8c\u5341\u3001\u4e3a\u4ec0\u4e48TCP\u5b57\u5178\u670d\u52a1\u5668\u8fd8\u9700\u8981\u5904\u7406\u6d88\u606f\u8fb9\u754c&#xff1f;<\/li>\n<li>\n<ul>\n<li>20.1 \u6211\u4eec\u600e\u6837\u89e3\u51b3&#xff1f;<\/li>\n<li>20.2 \u4e3a\u4ec0\u4e48\u6bcf\u4e2a\u5ba2\u6237\u7aef\u90fd\u9700\u8981\u81ea\u5df1\u7684\u63a5\u6536\u7f13\u51b2\u533a&#xff1f;<\/li>\n<\/ul>\n<\/li>\n<li>\u4e8c\u5341\u4e00\u3001\u5b8c\u6574\u5b9e\u73b0select_server.hpp<\/li>\n<li>\u4e8c\u5341\u4e8c\u3001\u9010\u6b65\u5206\u6790Selector\u7c7b<\/li>\n<li>\n<ul>\n<li>22.1 \u6784\u9020\u51fd\u6570<\/li>\n<li>22.2 Add\u51fd\u6570<\/li>\n<li>22.3 Del\u51fd\u6570<\/li>\n<li>22.4 Wait\u51fd\u6570<\/li>\n<li>22.5 \u4e3a\u4ec0\u4e48\u4e0d\u76f4\u63a5\u628a\u6574\u4e2aTcpSocket\u5bf9\u8c61\u590d\u5236\u5230\u96c6\u5408\u4e2d&#xff1f;<\/li>\n<\/ul>\n<\/li>\n<li>\u4e8c\u5341\u4e09\u3001\u9010\u6b65\u5206\u6790TcpSelectServer<\/li>\n<li>\n<ul>\n<li>23.1 \u521b\u5efa\u76d1\u542cSocket<\/li>\n<li>23.2 \u7ed1\u5b9a\u7aef\u53e3<\/li>\n<li>23.3 \u5f00\u59cb\u76d1\u542c<\/li>\n<li>23.4 \u4e3a\u4ec0\u4e48\u76d1\u542cSocket\u4e5f\u8981\u52a0\u5165select&#xff1f;<\/li>\n<li>23.5 \u4e3a\u4ec0\u4e48\u65b0\u5ba2\u6237\u7aef\u4e5f\u8981\u52a0\u5165select&#xff1f;<\/li>\n<li>23.6 \u5982\u679c\u5ba2\u6237\u7aef\u65ad\u5f00\u600e\u4e48\u529e&#xff1f;<\/li>\n<\/ul>\n<\/li>\n<li>\u4e8c\u5341\u56db\u3001\u5b8c\u6574\u5b9e\u73b0dict_server.cpp<\/li>\n<li>\n<ul>\n<li>24.1 \u4e3a\u4ec0\u4e48\u4f7f\u7528unordered_map&#xff1f;<\/li>\n<li>24.2 \u4e3a\u4ec0\u4e48\u4e1a\u52a1\u51fd\u6570\u4f7f\u7528Handler&#xff1f;<\/li>\n<li>24.3 \u4e3a\u4ec0\u4e48\u76d1\u542c127.0.0.1&#xff1f;<\/li>\n<\/ul>\n<\/li>\n<li>\u4e8c\u5341\u4e94\u3001\u7f16\u8bd1\u8fd0\u884cTCP\u5b57\u5178\u670d\u52a1\u5668<\/li>\n<li>\n<ul>\n<li>25.1 \u7f16\u8bd1<\/li>\n<li>25.2 \u542f\u52a8<\/li>\n<li>25.3 \u4f7f\u7528nc\u5ba2\u6237\u7aef\u6d4b\u8bd5<\/li>\n<li>25.4 \u4e3a\u4ec0\u4e48\u5fc5\u987b\u6309\u56de\u8f66&#xff1f;<\/li>\n<li>25.5 \u540c\u65f6\u6253\u5f00\u591a\u4e2a\u5ba2\u6237\u7aef<\/li>\n<li>25.6 \u6d4b\u8bd5\u4e00\u6279\u8fde\u7eed\u8bf7\u6c42<\/li>\n<\/ul>\n<\/li>\n<li>\u4e8c\u5341\u516d\u3001\u6574\u4e2aselect\u4e8b\u4ef6\u5faa\u73af\u7a76\u7adf\u53d1\u751f\u4e86\u4ec0\u4e48&#xff1f;<\/li>\n<li>\n<ul>\n<li>26.1 \u7b2c\u4e00\u8f6e&#xff1a;\u6ca1\u6709\u5ba2\u6237\u7aef\u6570\u636e<\/li>\n<li>26.2 \u7b2c\u4e8c\u8f6e&#xff1a;\u5ba2\u6237\u7aefB\u53d1\u9001\u6570\u636e<\/li>\n<li>26.3 \u7b2c\u4e09\u8f6e&#xff1a;\u5ba2\u6237\u7aefA\u548cC\u540c\u65f6\u53d1\u9001<\/li>\n<li>26.4 \u7b2c\u56db\u8f6e&#xff1a;\u5ba2\u6237\u7aefC\u65ad\u5f00\u8fde\u63a5<\/li>\n<\/ul>\n<\/li>\n<li>\u4e8c\u5341\u4e03\u3001\u8fd9\u4e2a\u670d\u52a1\u5668\u8fd8\u6709\u54ea\u4e9b\u9700\u8981\u6ce8\u610f\u7684\u5730\u65b9&#xff1f;<\/li>\n<li>\n<ul>\n<li>27.1 select\u53ea\u8d1f\u8d23\u62a5\u544a\u5c31\u7eea<\/li>\n<li>27.2 TCP\u4ecd\u7136\u662f\u5b57\u8282\u6d41<\/li>\n<li>27.3 \u5f53\u524d\u670d\u52a1\u5668\u4f7f\u7528\u963b\u585e\u5f0f\u53d1\u9001<\/li>\n<li>27.4 select\u8fd4\u56de\u540e&#xff0c;\u64cd\u4f5c\u5c31\u4e00\u5b9a\u6210\u529f\u5417&#xff1f;<\/li>\n<li>27.5 \u4e3a\u4ec0\u4e48\u4e0d\u80fd\u7b80\u5355\u590d\u5236Socket\u5bf9\u8c61&#xff1f;<\/li>\n<li>27.6 \u5982\u679c\u5ba2\u6237\u7aef\u6570\u91cf\u5f88\u591a\u600e\u4e48\u529e&#xff1f;<\/li>\n<\/ul>\n<\/li>\n<li>\u4e8c\u5341\u516b\u3001select\u5e38\u89c1\u9762\u8bd5\u95ee\u9898<\/li>\n<li>\n<ul>\n<li>28.1 select\u662f\u4ec0\u4e48&#xff1f;<\/li>\n<li>28.2 select\u548c\u963b\u585erecv\u6709\u4ec0\u4e48\u533a\u522b&#xff1f;<\/li>\n<li>28.3 select\u662f\u5426\u5c5e\u4e8e\u5f02\u6b65I\/O&#xff1f;<\/li>\n<li>28.4 select\u7684\u7b2c\u4e00\u4e2a\u53c2\u6570\u662f\u4ec0\u4e48&#xff1f;<\/li>\n<li>28.5 FD_ZERO\u662f\u4ec0\u4e48&#xff1f;<\/li>\n<li>28.6 FD_SET\u662f\u4ec0\u4e48&#xff1f;<\/li>\n<li>28.7 FD_ISSET\u662f\u4ec0\u4e48&#xff1f;<\/li>\n<li>28.8 \u4e3a\u4ec0\u4e48\u6bcf\u6b21\u8c03\u7528select\u524d\u8981\u91cd\u5efafd_set&#xff1f;<\/li>\n<li>28.9 select\u8fd4\u56de0\u662f\u4ec0\u4e48\u610f\u601d&#xff1f;<\/li>\n<li>28.10 \u4e3a\u4ec0\u4e48\u76d1\u542cSocket\u8bfb\u5c31\u7eea\u8981\u8c03\u7528accept&#xff1f;<\/li>\n<li>28.11 \u4e3a\u4ec0\u4e48\u5ba2\u6237\u7aefSocket\u8bfb\u5c31\u7eea\u540erecv\u53ef\u80fd\u8fd4\u56de0&#xff1f;<\/li>\n<li>28.12 \u4e3a\u4ec0\u4e48select\u8981\u7ef4\u62a4maxfd&#xff1f;<\/li>\n<li>28.13 select\u6700\u591a\u652f\u6301\u591a\u5c11\u4e2aSocket&#xff1f;<\/li>\n<li>28.14 select\u6700\u5927\u7684\u7f3a\u70b9\u662f\u4ec0\u4e48&#xff1f;<\/li>\n<\/ul>\n<\/li>\n<li>\u4e8c\u5341\u4e5d\u3001\u5168\u6587\u603b\u7ed3<\/li>\n<\/ul>\n<h3>\u524d\u8a00&#xff1a;\u4e3a\u4ec0\u4e48\u6709\u4e86\u975e\u963b\u585eIO&#xff0c;\u8fd8\u9700\u8981select&#xff1f;<\/h3>\n<p>\u5728\u524d\u9762\u7684Linux\u7f51\u7edc\u7f16\u7a0b\u4e2d&#xff0c;\u6211\u4eec\u5df2\u7ecf\u5b66\u4e60\u4e86\u4e94\u79cd\u7ecf\u5178I\/O\u6a21\u578b&#xff1a;<\/p>\n<li>\u963b\u585eI\/O<\/li>\n<li>\u975e\u963b\u585eI\/O<\/li>\n<li>\u4fe1\u53f7\u9a71\u52a8I\/O<\/li>\n<li>I\/O\u591a\u8def\u8f6c\u63a5<\/li>\n<li>\u5f02\u6b65I\/O<\/li>\n<p>\u5176\u4e2d&#xff0c;\u6211\u4eec\u901a\u8fc7 fcntl() \u914d\u5408&#xff1a;<\/p>\n<p>O_NONBLOCK<\/p>\n<p>\u5c06\u6587\u4ef6\u63cf\u8ff0\u7b26\u8bbe\u7f6e\u4e3a\u975e\u963b\u585e\u6a21\u5f0f\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p><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 punctuation\">;<\/span><\/p>\n<p><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 punctuation\">;<\/span><\/p>\n<p>\u8fd9\u6837&#xff0c;\u5728\u6ca1\u6709\u6570\u636e\u53ef\u8bfb\u65f6&#xff1a;<\/p>\n<p>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> 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>\u53ef\u4ee5\u7acb\u5373\u8fd4\u56de&#xff1a;<\/p>\n<p>-1<\/p>\n<p>\u5e76\u8bbe\u7f6e&#xff1a;<\/p>\n<p>errno <span class=\"token operator\">&#061;<\/span> EAGAIN<span class=\"token punctuation\">;<\/span><\/p>\n<p>\u800c\u4e0d\u9700\u8981\u8ba9\u5f53\u524d\u7ebf\u7a0b\u4e00\u76f4\u963b\u585e\u7b49\u5f85\u3002<\/p>\n<p>\u4f46\u662f&#xff0c;\u8fd9\u53c8\u5f15\u51fa\u4e86\u4e00\u4e2a\u65b0\u7684\u95ee\u9898\u3002<\/p>\n<p>\u5047\u8bbe\u6211\u4eec\u7684TCP\u670d\u52a1\u5668\u540c\u65f6\u8fde\u63a5\u4e86100\u4e2a\u5ba2\u6237\u7aef&#xff1a;<\/p>\n<p>\u5ba2\u6237\u7aef1  \u2192 sockfd1<\/p>\n<p>\u5ba2\u6237\u7aef2  \u2192 sockfd2<\/p>\n<p>\u5ba2\u6237\u7aef3  \u2192 sockfd3<\/p>\n<p>\u2026\u2026<\/p>\n<p>\u5ba2\u6237\u7aef100 \u2192 sockfd100<\/p>\n<p>\u5982\u679c\u4f7f\u7528\u7b80\u5355\u7684\u975e\u963b\u585e\u8f6e\u8be2&#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><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>sockfd1<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><br \/>\n    <span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>sockfd2<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><br \/>\n    <span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>sockfd3<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><br \/>\n    <span class=\"token comment\">\/\/ &#8230;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u670d\u52a1\u5668\u5c31\u9700\u8981\u4e0d\u65ad\u68c0\u67e5\u8fd9\u4e9bSocket\u3002<\/p>\n<p>\u5373\u4f7f\u5176\u4e2d99\u4e2a\u5ba2\u6237\u7aef\u90fd\u6ca1\u6709\u53d1\u9001\u4efb\u4f55\u6570\u636e&#xff0c;\u670d\u52a1\u5668\u4ecd\u7136\u53ef\u80fd\u53cd\u590d\u8c03\u7528\u5b83\u4eec\u5bf9\u5e94\u7684 recv()\u3002<\/p>\n<p>\u663e\u7136&#xff0c;\u8fd9\u79cd\u65b9\u5f0f\u53ef\u80fd\u4ea7\u751f\u5927\u91cf\u65e0\u610f\u4e49\u7684\u7cfb\u7edf\u8c03\u7528\u3002<\/p>\n<p>\u6211\u4eec\u771f\u6b63\u5e0c\u671b\u5b9e\u73b0\u7684\u662f&#xff1a;<\/p>\n<p>\u80fd\u4e0d\u80fd\u8ba9\u5185\u6838\u5e2e\u6211\u4eec\u540c\u65f6\u76d1\u89c6\u591a\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26&#xff0c;\u53ea\u6709\u5176\u4e2d\u67d0\u4e9b\u6587\u4ef6\u63cf\u8ff0\u7b26\u6ee1\u8db3\u8bfb\u5199\u6761\u4ef6\u65f6&#xff0c;\u624d\u901a\u77e5\u5e94\u7528\u7a0b\u5e8f\u5904\u7406&#xff1f;<\/p>\n<p>\u7b54\u6848\u662f\u53ef\u4ee5\u3002<\/p>\n<p>Linux\u63d0\u4f9b\u4e86&#xff1a;<\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u7cfb\u7edf\u8c03\u7528\u3002<\/p>\n<p>\u5b83\u662fI\/O\u591a\u8def\u8f6c\u63a5\u7684\u4e00\u79cd\u7ecf\u5178\u5b9e\u73b0\u3002<\/p>\n<hr \/>\n<h2>\u4e00\u3001\u4ec0\u4e48\u662fI\/O\u591a\u8def\u8f6c\u63a5&#xff1f;<\/h2>\n<p>I\/O\u591a\u8def\u8f6c\u63a5&#xff0c;\u4e5f\u79f0\u4e3a&#xff1a;<\/p>\n<p>I\/O Multiplexing\u3002<\/p>\n<p>\u5b83\u7684\u6838\u5fc3\u601d\u60f3\u662f&#xff1a;<\/p>\n<p>\u8ba9\u4e00\u4e2a\u6267\u884c\u6d41\u901a\u8fc7\u4e00\u4e2a\u7edf\u4e00\u7684\u7b49\u5f85\u63a5\u53e3&#xff0c;\u540c\u65f6\u5173\u6ce8\u591a\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26\u7684\u5c31\u7eea\u72b6\u6001\u3002<\/p>\n<h3>1.1 \u666e\u901a\u963b\u585eI\/O\u7684\u95ee\u9898<\/h3>\n<p>\u5047\u8bbe\u670d\u52a1\u5668\u8fde\u63a5\u4e86\u4e09\u4e2a\u5ba2\u6237\u7aef\u3002<\/p>\n<p>\u5ba2\u6237\u7aefA<br \/>\n   |<br \/>\n   v<br \/>\nSocket A<\/p>\n<p>\u5ba2\u6237\u7aefB<br \/>\n   |<br \/>\n   v<br \/>\nSocket B<\/p>\n<p>\u5ba2\u6237\u7aefC<br \/>\n   |<br \/>\n   v<br \/>\nSocket C<\/p>\n<p>\u5982\u679c\u670d\u52a1\u5668\u9996\u5148\u8c03\u7528&#xff1a;<\/p>\n<p><span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>sockfdA<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><\/p>\n<p>\u5f53\u5ba2\u6237\u7aefA\u6ca1\u6709\u53d1\u9001\u6570\u636e\u65f6&#xff0c;\u5f53\u524d\u7ebf\u7a0b\u53ef\u80fd\u963b\u585e\u5728\u8fd9\u4e2a\u51fd\u6570\u4e2d\u3002<\/p>\n<p>\u5373\u4f7f&#xff1a;<\/p>\n<p>\u5ba2\u6237\u7aefB\u5df2\u7ecf\u53d1\u9001\u6570\u636e<\/p>\n<p>\u4e5f\u65e0\u6cd5\u7acb\u5373\u5904\u7406&#xff0c;\u56e0\u4e3a\u5f53\u524d\u7ebf\u7a0b\u8fd8\u505c\u7559\u5728\u5ba2\u6237\u7aefA\u7684 recv() \u4e0a\u3002<\/p>\n<h3>1.2 \u975e\u963b\u585e\u8f6e\u8be2\u7684\u6539\u8fdb\u4e0e\u95ee\u9898<\/h3>\n<p>\u5982\u679c\u628a\u4e09\u4e2aSocket\u5168\u90e8\u8bbe\u7f6e\u4e3a\u975e\u963b\u585e&#xff1a;<\/p>\n<p>\u8bfb\u53d6A&#xff1a;\u6ca1\u6709\u6570\u636e \u2192 EAGAIN<\/p>\n<p>\u8bfb\u53d6B&#xff1a;\u6709\u6570\u636e \u2192 \u8bfb\u53d6\u6210\u529f<\/p>\n<p>\u8bfb\u53d6C&#xff1a;\u6ca1\u6709\u6570\u636e \u2192 EAGAIN<\/p>\n<p>\u5c31\u907f\u514d\u4e86\u5728\u5355\u4e2aSocket\u4e0a\u4e00\u76f4\u7b49\u5f85\u3002<\/p>\n<p>\u4f46\u662f&#xff0c;\u5982\u679cSocket\u6570\u91cf\u8fbe\u5230&#xff1a;<\/p>\n<p>1000\u4e2a<\/p>\n<p>10000\u4e2a<\/p>\n<p>\u4e0d\u505c\u8f6e\u8be2\u53ef\u80fd\u4f1a\u9020\u6210\u8f83\u5927\u5f00\u9500\u3002<\/p>\n<h3>1.3 select\u7684\u89e3\u51b3\u65b9\u6848<\/h3>\n<p>select() \u7684\u601d\u8def\u662f&#xff1a;<\/p>\n<p>\u5148\u8ba9\u5185\u6838\u7b49\u5f85\u591a\u4e2a\u63cf\u8ff0\u7b26\u7684\u5c31\u7eea\u6761\u4ef6&#xff0c;\u7b49\u5230\u81f3\u5c11\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6&#xff0c;\u518d\u8ba9\u5e94\u7528\u7a0b\u5e8f\u5904\u7406\u76f8\u5e94\u63cf\u8ff0\u7b26\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>              \u5e94\u7528\u7a0b\u5e8f<br \/>\n                  |<br \/>\n                  v<br \/>\n               select<br \/>\n                  |<br \/>\n       &#043;&#8212;&#8212;&#8212;-&#043;&#8212;&#8212;&#8212;-&#043;<br \/>\n       |          |          |<br \/>\n       v          v          v<br \/>\n    sockfdA    sockfdB    sockfdC<br \/>\n       |          |          |<br \/>\n     \u672a\u5c31\u7eea      \u5df2\u5c31\u7eea      \u672a\u5c31\u7eea<br \/>\n                  |<br \/>\n                  v<br \/>\n             select\u8fd4\u56de<br \/>\n                  |<br \/>\n                  v<br \/>\n             \u5904\u7406sockfdB<\/p>\n<p>\u56e0\u6b64&#xff1a;<\/p>\n<p>\u5e94\u7528\u7a0b\u5e8f\u4e0d\u9700\u8981\u6301\u7eed\u53cd\u590d\u5c1d\u8bd5\u8bfb\u53d6\u6240\u6709Socket<\/p>\n<p>\u800c\u53ef\u4ee5&#xff1a;<\/p>\n<p>\u7b49\u5f85\u5185\u6838\u62a5\u544a\u54ea\u4e9bSocket\u5df2\u7ecf\u6ee1\u8db3\u6761\u4ef6<\/p>\n<h3>1.4 select\u662f\u4e0d\u662f\u5f02\u6b65I\/O&#xff1f;<\/h3>\n<p>\u4e0d\u662f\u3002<\/p>\n<p>\u5728\u7ecf\u5178\u4e94\u79cdI\/O\u6a21\u578b\u4e2d&#xff0c;select\u5c5e\u4e8e&#xff1a;<\/p>\n<p>\u540c\u6b65I\/O\u591a\u8def\u8f6c\u63a5\u3002<\/p>\n<p>\u56e0\u4e3a&#xff1a;<\/p>\n<p>select\u8d1f\u8d23\u7b49\u5f85\u5c31\u7eea\u4e8b\u4ef6<\/p>\n<p>\u800c&#xff1a;<\/p>\n<p>read \/ recv\u8d1f\u8d23\u771f\u6b63\u8bfb\u53d6\u6570\u636e<\/p>\n<p>\u6574\u4e2a\u8fc7\u7a0b&#xff1a;<\/p>\n<p>select\u7b49\u5f85<br \/>\n    |<br \/>\n    v<br \/>\n\u53d1\u73b0Socket\u5c31\u7eea<br \/>\n    |<br \/>\n    v<br \/>\n\u5e94\u7528\u7a0b\u5e8f\u8c03\u7528recv<br \/>\n    |<br \/>\n    v<br \/>\n\u6570\u636e\u62f7\u8d1d\u5230\u7528\u6237\u7a7a\u95f4<br \/>\n    |<br \/>\n    v<br \/>\n\u5e94\u7528\u7a0b\u5e8f\u5904\u7406\u6570\u636e<\/p>\n<p>select\u5e76\u4e0d\u4f1a\u81ea\u52a8\u66ff\u5e94\u7528\u7a0b\u5e8f\u5b8c\u6210\u6574\u4e2a\u8bfb\u53d6\u64cd\u4f5c\u3002<\/p>\n<h3>1.5 select\u4e00\u5b9a\u4e0d\u4f1a\u963b\u585e\u5417&#xff1f;<\/h3>\n<p>\u6070\u6070\u76f8\u53cd\u3002<\/p>\n<p>select() \u672c\u8eab\u901a\u5e38\u5c31\u662f\u4e00\u4e2a\u53ef\u4ee5\u963b\u585e\u7b49\u5f85\u7684\u7cfb\u7edf\u8c03\u7528\u3002<\/p>\n<p>\u4f46\u5b83\u548c\u76f4\u63a5\u963b\u585e\u5728\u67d0\u4e00\u4e2aSocket\u4e0a\u7684 recv() \u4e0d\u540c&#xff1a;<\/p>\n<p>\u666e\u901a\u963b\u585erecv&#xff1a;<\/p>\n<p>\u7b49\u5f85\u4e00\u4e2aSocket\u4e0a\u7684\u8bfb\u53d6\u6761\u4ef6<\/p>\n<p>select&#xff1a;<\/p>\n<p>\u540c\u65f6\u7b49\u5f85\u591a\u4e2a\u63cf\u8ff0\u7b26\u7684\u5c31\u7eea\u6761\u4ef6<\/p>\n<p>\u56e0\u6b64&#xff1a;<\/p>\n<p>select\u7684\u4ef7\u503c\u4e0d\u662f\u8ba9\u7ebf\u7a0b\u6c38\u8fdc\u4e0d\u963b\u585e&#xff0c;\u800c\u662f\u63d0\u9ad8\u4e00\u4e2a\u7ebf\u7a0b\u7b49\u5f85\u591a\u4e2aI\/O\u5bf9\u8c61\u65f6\u7684\u6548\u7387\u3002<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/11\/20261106001815-6aed1cc71ef4b.png\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\" \/><\/p>\n<hr \/>\n<h2>\u4e8c\u3001select\u51fd\u6570\u539f\u578b<\/h2>\n<p>Linux\u63d0\u4f9b\u4e86&#xff1a;<\/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;sys\/select.h&gt;<\/span><\/span><\/p>\n<p>\u5176\u4e2d\u5b9a\u4e49\u4e86&#xff1a;<\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> nfds<span class=\"token punctuation\">,<\/span><br \/>\n    fd_set <span class=\"token operator\">*<\/span>readfds<span class=\"token punctuation\">,<\/span><br \/>\n    fd_set <span class=\"token operator\">*<\/span>writefds<span class=\"token punctuation\">,<\/span><br \/>\n    fd_set <span class=\"token operator\">*<\/span>exceptfds<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">timeval<\/span> <span class=\"token operator\">*<\/span>timeout<br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8fd9\u4e2a\u51fd\u6570\u6709\u4e94\u4e2a\u53c2\u6570\u3002<\/p>\n<p>\u521d\u6b21\u63a5\u89e6\u65f6&#xff0c;\u53ef\u80fd\u89c9\u5f97\u975e\u5e38\u590d\u6742\u3002<\/p>\n<p>\u4f46\u5b9e\u9645\u4e0a\u53ef\u4ee5\u5206\u4e3a\u4e09\u7ec4&#xff1a;<\/p>\n<p>nfds&#xff1a;<\/p>\n<p>\u544a\u8bc9\u5185\u6838\u8981\u68c0\u67e5\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26\u7f16\u53f7\u8303\u56f4<\/p>\n<p>readfds \/ writefds \/ exceptfds&#xff1a;<\/p>\n<p>\u544a\u8bc9\u5185\u6838\u9700\u8981\u5173\u6ce8\u54ea\u4e9b\u5c31\u7eea\u6761\u4ef6<\/p>\n<p>timeout&#xff1a;<\/p>\n<p>\u544a\u8bc9\u5185\u6838\u6700\u591a\u7b49\u5f85\u591a\u957f\u65f6\u95f4<\/p>\n<p>\u63a5\u4e0b\u6765\u9010\u4e2a\u8bb2\u89e3\u3002<\/p>\n<hr \/>\n<h2>\u4e09\u3001\u7b2c\u4e00\u4e2a\u53c2\u6570nfds\u662f\u4ec0\u4e48\u610f\u601d&#xff1f;<\/h2>\n<p>\u51fd\u6570\u539f\u578b&#xff1a;<\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> nfds<span class=\"token punctuation\">,<\/span><br \/>\n    fd_set <span class=\"token operator\">*<\/span>readfds<span class=\"token punctuation\">,<\/span><br \/>\n    fd_set <span class=\"token operator\">*<\/span>writefds<span class=\"token punctuation\">,<\/span><br \/>\n    fd_set <span class=\"token operator\">*<\/span>exceptfds<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">timeval<\/span> <span class=\"token operator\">*<\/span>timeout<br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5176\u4e2d&#xff1a;<\/p>\n<p>nfds<\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>\u9700\u8981\u68c0\u67e5\u7684\u6700\u5927\u6587\u4ef6\u63cf\u8ff0\u7b26\u7f16\u53f7\u52a01\u3002<\/p>\n<h3>3.1 \u4e3a\u4ec0\u4e48\u4e0d\u662f\u6587\u4ef6\u63cf\u8ff0\u7b26\u6570\u91cf&#xff1f;<\/h3>\n<p>\u5047\u8bbe\u6211\u4eec\u9700\u8981\u76d1\u89c6\u4e09\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26&#xff1a;<\/p>\n<p>fd &#061; 3<\/p>\n<p>fd &#061; 5<\/p>\n<p>fd &#061; 8<\/p>\n<p>\u867d\u7136\u53ea\u6709\u4e09\u4e2a\u63cf\u8ff0\u7b26&#xff0c;\u4f46\u662f\u6700\u5927\u7f16\u53f7\u662f&#xff1a;<\/p>\n<p>8<\/p>\n<p>\u56e0\u6b64&#xff1a;<\/p>\n<p>nfds <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">8<\/span> <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5373&#xff1a;<\/p>\n<p>nfds <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">9<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8c03\u7528&#xff1a;<\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">9<\/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<h3>3.2 \u4e3a\u4ec0\u4e48\u8981\u52a01&#xff1f;<\/h3>\n<p>\u56e0\u4e3a\u6587\u4ef6\u63cf\u8ff0\u7b26\u4ece0\u5f00\u59cb\u7f16\u53f7\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>0 1 2 3 4 5 6 7 8<\/p>\n<p>\u5982\u679c\u8981\u68c0\u67e5\u7684\u6700\u5927\u63cf\u8ff0\u7b26\u4e3a8&#xff0c;\u90a3\u4e48\u9700\u8981\u8003\u8651&#xff1a;<\/p>\n<p>0&#xff5e;8<\/p>\n<p>\u8fd9\u4e9b\u53ef\u80fd\u7684\u7f16\u53f7\u4f4d\u7f6e\u3002<\/p>\n<p>\u6240\u4ee5&#xff1a;<\/p>\n<p><span class=\"katex--display\"><span class=\"katex-display\"><span class=\"katex\"><span class=\"katex-mathml\"><\/p>\n<p>         n<\/p>\n<p>         f<\/p>\n<p>         d<\/p>\n<p>         s<\/p>\n<p>         &#061;<\/p>\n<p>         m<\/p>\n<p>         a<\/p>\n<p>         x<\/p>\n<p>         f<\/p>\n<p>         d<\/p>\n<p>         &#043;<\/p>\n<p>         1<\/p>\n<p>         nfds&#061;maxfd&#043;1 <\/p>\n<p>     <\/span><span class=\"katex-html\"><span class=\"base\"><span class=\"strut\" style=\"height: 0.8889em;vertical-align: -0.1944em\"><\/span><span class=\"mord mathnormal\">n<\/span><span class=\"mord mathnormal\" style=\"margin-right: 0.1076em\">f<\/span><span class=\"mord mathnormal\">d<\/span><span class=\"mord mathnormal\">s<\/span><span class=\"mspace\" style=\"margin-right: 0.2778em\"><\/span><span class=\"mrel\">&#061;<\/span><span class=\"mspace\" style=\"margin-right: 0.2778em\"><\/span><\/span><span class=\"base\"><span class=\"strut\" style=\"height: 0.8889em;vertical-align: -0.1944em\"><\/span><span class=\"mord mathnormal\">ma<\/span><span class=\"mord mathnormal\">x<\/span><span class=\"mord mathnormal\" style=\"margin-right: 0.1076em\">f<\/span><span class=\"mord mathnormal\">d<\/span><span class=\"mspace\" style=\"margin-right: 0.2222em\"><\/span><span class=\"mbin\">&#043;<\/span><span class=\"mspace\" style=\"margin-right: 0.2222em\"><\/span><\/span><span class=\"base\"><span class=\"strut\" style=\"height: 0.6444em\"><\/span><span class=\"mord\">1<\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n<h3>3.3 \u53e6\u4e00\u4e2a\u4f8b\u5b50<\/h3>\n<p>\u5047\u8bbe\u76d1\u89c6&#xff1a;<\/p>\n<p>fd &#061; 4<\/p>\n<p>fd &#061; 7<\/p>\n<p>fd &#061; 12<\/p>\n<p>\u6700\u5927\u503c&#xff1a;<\/p>\n<p>12<\/p>\n<p>\u56e0\u6b64&#xff1a;<\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">13<\/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>\u6ce8\u610f&#xff1a;<\/p>\n<p>nfds\u4e0d\u662f\u9700\u8981\u76d1\u89c6\u7684\u63cf\u8ff0\u7b26\u4e2a\u6570&#xff0c;\u800c\u662f\u6700\u5927\u63cf\u8ff0\u7b26\u7f16\u53f7\u52a01\u3002<\/p>\n<p>\u8fd9\u662f\u4f7f\u7528select\u65f6\u6700\u5bb9\u6613\u51fa\u9519\u7684\u5730\u65b9\u4e4b\u4e00\u3002<\/p>\n<hr \/>\n<h2>\u56db\u3001readfds\u3001writefds\u3001exceptfds\u5206\u522b\u662f\u4ec0\u4e48&#xff1f;<\/h2>\n<p>select\u53ef\u4ee5\u76d1\u89c6\u4e09\u79cd\u7c7b\u578b\u7684\u4e8b\u4ef6\u3002<\/p>\n<p>fd_set <span class=\"token operator\">*<\/span>readfds<span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>\u9700\u8981\u68c0\u67e5\u53ef\u8bfb\u72b6\u6001\u7684\u63cf\u8ff0\u7b26\u96c6\u5408\u3002<\/p>\n<p>fd_set <span class=\"token operator\">*<\/span>writefds<span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>\u9700\u8981\u68c0\u67e5\u53ef\u5199\u72b6\u6001\u7684\u63cf\u8ff0\u7b26\u96c6\u5408\u3002<\/p>\n<p>fd_set <span class=\"token operator\">*<\/span>exceptfds<span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>\u9700\u8981\u68c0\u67e5\u5f02\u5e38\u6761\u4ef6\u7684\u63cf\u8ff0\u7b26\u96c6\u5408\u3002<\/p>\n<h3>4.1 readfds&#xff1a;\u8bfb\u5c31\u7eea\u96c6\u5408<\/h3>\n<p>\u5047\u8bbe\u6211\u4eec\u5e0c\u671b\u68c0\u67e5&#xff1a;<\/p>\n<p>sockfd1\u662f\u5426\u53ef\u8bfb&#xff1f;<\/p>\n<p>sockfd2\u662f\u5426\u53ef\u8bfb&#xff1f;<\/p>\n<p>sockfd3\u662f\u5426\u53ef\u8bfb&#xff1f;<\/p>\n<p>\u90a3\u4e48\u5c31\u9700\u8981\u628a\u8fd9\u4e09\u4e2a\u63cf\u8ff0\u7b26\u52a0\u5165&#xff1a;<\/p>\n<p>readfds<\/p>\n<p>\u96c6\u5408\u3002<\/p>\n<p>\u8c03\u7528select\u4ee5\u540e&#xff0c;\u53ef\u4ee5\u68c0\u67e5\u54ea\u4e9b\u63cf\u8ff0\u7b26\u6ee1\u8db3\u53ef\u8bfb\u6761\u4ef6\u3002<\/p>\n<h3>4.2 writefds&#xff1a;\u5199\u5c31\u7eea\u96c6\u5408<\/h3>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>\u67d0\u4e2aSocket\u5f53\u524d\u662f\u5426\u80fd\u591f\u8fdb\u884c\u5199\u64cd\u4f5c&#xff1f;<\/p>\n<p>\u5c31\u53ef\u4ee5\u4f7f\u7528&#xff1a;<\/p>\n<p>writefds<\/p>\n<p>\u4f46\u8fd9\u91cc\u7684\u201c\u53ef\u5199\u201d\u4e0d\u8868\u793a\u65e0\u8bba\u53d1\u9001\u591a\u5c11\u6570\u636e\u90fd\u7edd\u5bf9\u4e0d\u4f1a\u7b49\u5f85\u3002<\/p>\n<p>\u5b83\u901a\u5e38\u8868\u793a&#xff1a;<\/p>\n<p>\u5f53\u524d\u6ee1\u8db3\u4e00\u5b9a\u7684\u5199\u5165\u5c31\u7eea\u6761\u4ef6\u3002<\/p>\n<p>\u5982\u679c\u5c1d\u8bd5\u53d1\u9001\u5927\u91cf\u6570\u636e&#xff0c;\u4ecd\u7136\u53ef\u80fd\u51fa\u73b0\u90e8\u5206\u5199\u5165\u6216\u5176\u4ed6\u60c5\u51b5\u3002<\/p>\n<h3>4.3 exceptfds&#xff1a;\u5f02\u5e38\u6761\u4ef6\u96c6\u5408<\/h3>\n<p>\u7528\u4e8e\u76d1\u89c6\u7279\u5b9a\u7684\u5f02\u5e38\u6761\u4ef6\u3002<\/p>\n<p>\u4f8b\u5982TCP\u5e26\u5916\u6570\u636e\u76f8\u5173\u7684\u5f02\u5e38\u5c31\u7eea\u60c5\u51b5\u3002<\/p>\n<p>\u9700\u8981\u7279\u522b\u6ce8\u610f&#xff1a;<\/p>\n<p>exceptfds\u4e0d\u662f\u666e\u901aSocket\u9519\u8bef\u4e8b\u4ef6\u7684\u603b\u96c6\u5408\u3002<\/p>\n<p>\u4e0d\u80fd\u628a&#xff1a;<\/p>\n<p>exceptfds<\/p>\n<p>\u7b80\u5355\u7406\u89e3\u4e3a&#xff1a;<\/p>\n<p>\u6240\u6709\u7f51\u7edc\u5f02\u5e38\u90fd\u5728\u8fd9\u91cc\u62a5\u544a<\/p>\n<p>\u5f53\u524d\u9636\u6bb5\u53ea\u9700\u8981\u77e5\u9053\u5b83\u7684\u5b58\u5728\u5373\u53ef\u3002<\/p>\n<h3>4.4 \u5982\u679c\u53ea\u9700\u8981\u76d1\u89c6\u8bfb\u4e8b\u4ef6\u600e\u4e48\u529e&#xff1f;<\/h3>\n<p>\u53ef\u4ee5\u5c06\u5176\u4ed6\u96c6\u5408\u8bbe\u7f6e\u4e3a&#xff1a;<\/p>\n<p><span class=\"token constant\">NULL<\/span><\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><br \/>\n    maxfd <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>readfds<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token constant\">NULL<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>\u53ea\u68c0\u67e5readfds\u4e2d\u7684\u53ef\u8bfb\u4e8b\u4ef6<\/p>\n<p>\u4e0d\u68c0\u67e5&#xff1a;<\/p>\n<p>writefds<\/p>\n<p>exceptfds<\/p>\n<p>\u672c\u7bc7\u7684\u5b57\u5178\u670d\u52a1\u5668\u9996\u5148\u5c31\u91c7\u7528\u8fd9\u79cd\u65b9\u5f0f\u3002<\/p>\n<hr \/>\n<h2>\u4e94\u3001\u7b2c\u4e94\u4e2a\u53c2\u6570timeout\u662f\u4ec0\u4e48\u610f\u601d&#xff1f;<\/h2>\n<p>select() \u7684\u6700\u540e\u4e00\u4e2a\u53c2\u6570&#xff1a;<\/p>\n<p><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">timeval<\/span> <span class=\"token operator\">*<\/span>timeout<span class=\"token punctuation\">;<\/span><\/p>\n<p>\u7528\u4e8e\u63a7\u5236\u7b49\u5f85\u65f6\u95f4\u3002<\/p>\n<h3>5.1 timeval\u7ed3\u6784<\/h3>\n<p>\u901a\u5e38\u53ef\u4ee5\u7406\u89e3\u4e3a&#xff1a;<\/p>\n<p><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">timeval<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    time_t tv_sec<span class=\"token punctuation\">;<\/span><br \/>\n    suseconds_t tv_usec<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<p>tv_sec<\/p>\n<p>\u8868\u793a\u79d2\u3002<\/p>\n<p>tv_usec<\/p>\n<p>\u8868\u793a\u5fae\u79d2\u3002<\/p>\n<p>\u9700\u8981\u6ce8\u610f&#xff1a;<\/p>\n<p><span class=\"katex--display\"><span class=\"katex-display\"><span class=\"katex\"><span class=\"katex-mathml\"><\/p>\n<p>         1<\/p>\n<p>         \u79d2<\/p>\n<p>         &#061;<\/p>\n<p>         1000000<\/p>\n<p>         \u5fae\u79d2<\/p>\n<p>         1\\\\text{\u79d2}&#061;1000000\\\\text{\u5fae\u79d2} <\/p>\n<p>     <\/span><span class=\"katex-html\"><span class=\"base\"><span class=\"strut\" style=\"height: 0.6833em\"><\/span><span class=\"mord\">1<\/span><span class=\"mord text\"><span class=\"mord cjk_fallback\">\u79d2<\/span><\/span><span class=\"mspace\" style=\"margin-right: 0.2778em\"><\/span><span class=\"mrel\">&#061;<\/span><span class=\"mspace\" style=\"margin-right: 0.2778em\"><\/span><\/span><span class=\"base\"><span class=\"strut\" style=\"height: 0.6833em\"><\/span><span class=\"mord\">1000000<\/span><span class=\"mord text\"><span class=\"mord cjk_fallback\">\u5fae\u79d2<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">timeval<\/span> timeout<span class=\"token punctuation\">;<\/span><\/p>\n<p>timeout<span class=\"token punctuation\">.<\/span>tv_sec <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">2<\/span><span class=\"token punctuation\">;<\/span><br \/>\ntimeout<span class=\"token punctuation\">.<\/span>tv_usec <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">500000<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>2.5\u79d2<\/p>\n<h3>5.2 \u7b2c\u4e00\u79cd\u60c5\u51b5&#xff1a;timeout\u4e3aNULL<\/h3>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><br \/>\n    maxfd <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>readfds<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token constant\">NULL<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8fd9\u91cc\u6700\u540e\u4e00\u4e2a\u53c2\u6570\u4e3a&#xff1a;<\/p>\n<p><span class=\"token constant\">NULL<\/span><\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>\u4e0d\u8bbe\u7f6e\u8d85\u65f6\u671f\u9650\u3002<\/p>\n<p>\u5982\u679c\u6ca1\u6709\u63cf\u8ff0\u7b26\u6ee1\u8db3\u5c31\u7eea\u6761\u4ef6&#xff0c;select\u53ef\u4ee5\u4e00\u76f4\u7b49\u5f85\u3002<\/p>\n<p>\u76f4\u5230\u51fa\u73b0&#xff1a;<\/p>\n<p>\u67d0\u4e9b\u63cf\u8ff0\u7b26\u5c31\u7eea<\/p>\n<p>\u4fe1\u53f7\u4e2d\u65ad<\/p>\n<p>\u7cfb\u7edf\u8c03\u7528\u9519\u8bef<\/p>\n<p>\u7b49\u60c5\u51b5\u3002<\/p>\n<p>\u6240\u4ee5\u5e76\u4e0d\u662f\u4e25\u683c\u610f\u4e49\u4e0a\u7684\u201c\u6c38\u8fdc\u65e0\u6cd5\u8fd4\u56de\u201d\u3002<\/p>\n<h3>5.3 \u7b2c\u4e8c\u79cd\u60c5\u51b5&#xff1a;timeout\u4e3a0<\/h3>\n<p>\u6ce8\u610f&#xff0c;\u8fd9\u91cc\u7684timeout\u4e3a0&#xff0c;\u901a\u5e38\u662f\u6307&#xff1a;<\/p>\n<p><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">timeval<\/span> timeout <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">{<\/span><span class=\"token number\">0<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u7136\u540e&#xff1a;<\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><br \/>\n    maxfd <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>readfds<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token operator\">&amp;<\/span>timeout<br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8fd9\u6837\u8868\u793a&#xff1a;<\/p>\n<p>\u53ea\u68c0\u67e5\u5f53\u524d\u72b6\u6001&#xff0c;\u7136\u540e\u7acb\u5373\u8fd4\u56de&#xff0c;\u4e0d\u7b49\u5f85\u5916\u90e8\u4e8b\u4ef6\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>\u5f53\u524d\u6709\u5c31\u7eea\u63cf\u8ff0\u7b26&#xff1a;<\/p>\n<p>\u8fd4\u56de\u5c31\u7eea\u4fe1\u606f<\/p>\n<p>\u5f53\u524d\u6ca1\u6709\u5c31\u7eea\u63cf\u8ff0\u7b26&#xff1a;<\/p>\n<p>\u7acb\u5373\u8fd4\u56de0<\/p>\n<h3>5.4 \u7b2c\u4e09\u79cd\u60c5\u51b5&#xff1a;\u6307\u5b9a\u8d85\u65f6\u65f6\u95f4<\/h3>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">timeval<\/span> timeout <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">{<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>\u6700\u591a\u7b49\u5f855\u79d2<\/p>\n<p>\u8c03\u7528&#xff1a;<\/p>\n<p><span class=\"token keyword\">int<\/span> ret <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><br \/>\n    maxfd <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>readfds<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token operator\">&amp;<\/span>timeout<br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5982\u679c5\u79d2\u5185\u6ca1\u6709\u5bf9\u5e94\u5c31\u7eea\u4e8b\u4ef6&#xff1a;<\/p>\n<p>ret <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><\/p>\n<p>\u5982\u679c\u57285\u79d2\u5185\u6709\u63cf\u8ff0\u7b26\u5c31\u7eea&#xff1a;<\/p>\n<p>ret <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><\/p>\n<p>\u5219\u53ef\u4ee5\u63d0\u524d\u8fd4\u56de\u3002<\/p>\n<h3>5.5 \u4e09\u79cd\u6a21\u5f0f\u603b\u7ed3<\/h3>\n<table>\n<tr>timeout\u542b\u4e49<\/tr>\n<tbody>\n<tr>\n<td>NULL<\/td>\n<td>\u4e0d\u8bbe\u7f6e\u8d85\u65f6\u671f\u9650&#xff0c;\u53ef\u6301\u7eed\u963b\u585e\u7b49\u5f85<\/td>\n<\/tr>\n<tr>\n<td>{0, 0}<\/td>\n<td>\u7acb\u5373\u68c0\u6d4b&#xff0c;\u4e0d\u7b49\u5f85<\/td>\n<\/tr>\n<tr>\n<td>{5, 0}<\/td>\n<td>\u6700\u591a\u7b49\u5f85\u7ea65\u79d2<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u9700\u8981\u6ce8\u610f&#xff0c;\u5b9e\u9645\u7b49\u5f85\u65f6\u957f\u8fd8\u53ef\u80fd\u53d7\u5230\u7cfb\u7edf\u8c03\u5ea6\u548c\u4fe1\u53f7\u7b49\u56e0\u7d20\u5f71\u54cd\u3002<\/p>\n<p>\u6b64\u5916&#xff0c;\u5728Linux\u4e0a&#xff0c;select\u53ef\u80fd\u4fee\u6539\u4f20\u5165\u7684 timeval\u3002<\/p>\n<p>\u56e0\u6b64\u5982\u679c\u9700\u8981\u91cd\u590d\u4f7f\u7528\u56fa\u5b9a\u7684\u8d85\u65f6\u65f6\u95f4&#xff1a;<\/p>\n<p>\u6700\u597d\u5728\u6bcf\u6b21\u8c03\u7528select\u4e4b\u524d\u91cd\u65b0\u521d\u59cb\u5316timeval\u3002<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/11\/20261106001816-6aed1cc88917c.png\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\" \/><\/p>\n<hr \/>\n<h2>\u516d\u3001\u4ec0\u4e48\u662ffd_set&#xff1f;<\/h2>\n<p>\u73b0\u5728\u6b63\u5f0f\u5b66\u4e60select\u7684\u6838\u5fc3\u6570\u636e\u7ed3\u6784&#xff1a;<\/p>\n<p>fd_set<\/p>\n<p>\u524d\u9762\u4e00\u76f4\u5728\u8bf4&#xff1a;<\/p>\n<p>\u53ef\u8bfb\u96c6\u5408<\/p>\n<p>\u53ef\u5199\u96c6\u5408<\/p>\n<p>\u5f02\u5e38\u96c6\u5408<\/p>\n<p>\u90a3\u4e48&#xff1a;<\/p>\n<p>select\u7a76\u7adf\u600e\u6837\u8868\u793a\u4e00\u7ec4\u6587\u4ef6\u63cf\u8ff0\u7b26&#xff1f;<\/p>\n<p>\u7b54\u6848\u662f&#xff1a;<\/p>\n<p>\u4f7f\u7528fd_set\u3002<\/p>\n<h3>6.1 fd_set\u53ef\u4ee5\u7406\u89e3\u4e3a\u4f4d\u56fe<\/h3>\n<p>\u5728\u5e38\u89c1\u5b9e\u73b0\u4e2d&#xff1a;<\/p>\n<p>fd_set<\/p>\n<p>\u53ef\u4ee5\u7406\u89e3\u4e3a\u4f7f\u7528\u4f4d\u56fe\u8868\u793a\u6587\u4ef6\u63cf\u8ff0\u7b26\u96c6\u5408\u3002<\/p>\n<p>\u6240\u8c13\u4f4d\u56fe&#xff0c;\u5c31\u662f&#xff1a;<\/p>\n<p>\u4f7f\u7528\u4e00\u4e2a\u4e8c\u8fdb\u5236\u4f4d\u8868\u793a\u67d0\u4e2a\u7f16\u53f7\u7684\u72b6\u6001\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>00000000<\/p>\n<p>\u8fd9\u662f\u4e00\u4e2a8\u4f4d\u7684\u793a\u610f\u4f4d\u56fe\u3002<\/p>\n<p>\u6211\u4eec\u6682\u65f6\u5047\u8bbe&#xff1a;<\/p>\n<p>bit0\u4ee3\u8868fd0<\/p>\n<p>bit1\u4ee3\u8868fd1<\/p>\n<p>bit2\u4ee3\u8868fd2<\/p>\n<p>\u2026\u2026<\/p>\n<p>bit7\u4ee3\u8868fd7<\/p>\n<p>\u5982\u679c&#xff1a;<\/p>\n<p>bit3 &#061; 1<\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>fd3\u5728\u96c6\u5408\u4e2d<\/p>\n<p>\u5982\u679c&#xff1a;<\/p>\n<p>bit3 &#061; 0<\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>fd3\u4e0d\u5728\u96c6\u5408\u4e2d<\/p>\n<h3>6.2 \u4e3a\u4ec0\u4e48\u4f7f\u7528\u4f4d\u56fe&#xff1f;<\/h3>\n<p>\u56e0\u4e3a\u6587\u4ef6\u63cf\u8ff0\u7b26\u672c\u8d28\u4e0a\u662f\u6574\u6570\u7f16\u53f7\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>fd0<\/p>\n<p>fd1<\/p>\n<p>fd2<\/p>\n<p>fd3<\/p>\n<p>\u53ef\u4ee5\u76f4\u63a5\u5bf9\u5e94\u4f4d\u56fe\u4e2d\u7684\u4e0d\u540c\u4f4d\u7f6e\u3002<\/p>\n<p>\u8fd9\u6837\u5c31\u80fd\u591f\u7528\u7d27\u51d1\u7684\u6570\u636e\u7ed3\u6784\u8bb0\u5f55&#xff1a;<\/p>\n<p>\u54ea\u4e9b\u6587\u4ef6\u63cf\u8ff0\u7b26\u9700\u8981\u76d1\u89c6<\/p>\n<h3>6.3 fd_set\u662f\u4e0d\u662f\u4e00\u4e2a\u666e\u901a\u7684int\u6570\u7ec4&#xff1f;<\/h3>\n<p>\u4ece\u5b9e\u73b0\u89d2\u5ea6\u770b&#xff0c;\u5e38\u89c1Linux C\u5e93\u4e2d\u7684 fd_set \u53ef\u4ee5\u7531\u6574\u6570\u7c7b\u578b\u7684\u6570\u7ec4\u6784\u6210\u3002<\/p>\n<p>\u4f8b\u5982\u5178\u578b\u7684\u5386\u53f2\u5b9e\u73b0\u601d\u8def&#xff1a;<\/p>\n<p><span class=\"token keyword\">typedef<\/span> <span class=\"token keyword\">long<\/span> <span class=\"token keyword\">int<\/span> __fd_mask<span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">typedef<\/span> <span class=\"token keyword\">struct<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    __fd_mask fds_bits<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><br \/>\n<span class=\"token punctuation\">}<\/span> fd_set<span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8fd9\u6bb5\u4ee3\u7801\u4ec5\u7528\u4e8e\u89e3\u91ca\u4f4d\u56fe\u601d\u60f3\u3002<\/p>\n<p>\u4e0d\u540c\u7cfb\u7edf\u4e0eC\u5e93\u7248\u672c\u7684\u5185\u90e8\u7ed3\u6784\u4f53\u540d\u79f0\u3001\u6210\u5458\u540d\u548c\u5b9e\u73b0\u7ec6\u8282\u53ef\u80fd\u6709\u6240\u4e0d\u540c\u3002<\/p>\n<p>\u5b9e\u9645\u7a0b\u5e8f\u4e0d\u5e94\u8be5\u76f4\u63a5\u64cd\u4f5c\u8fd9\u4e9b\u5185\u90e8\u6210\u5458&#xff0c;\u800c\u5e94\u8be5\u4f7f\u7528\u6807\u51c6\u5b8f&#xff1a;<\/p>\n<p>FD_ZERO<\/p>\n<p>FD_SET<\/p>\n<p>FD_CLR<\/p>\n<p>FD_ISSET<\/p>\n<p>\u8fd9\u6837\u4ee3\u7801\u624d\u66f4\u5bb9\u6613\u7406\u89e3&#xff0c;\u4e5f\u66f4\u7b26\u5408\u89c4\u8303\u63a5\u53e3\u7684\u4f7f\u7528\u65b9\u5f0f\u3002<\/p>\n<hr \/>\n<h2>\u4e03\u3001\u64cd\u4f5cfd_set\u7684\u56db\u4e2a\u91cd\u8981\u5b8f<\/h2>\n<p>Linux\u4e3a\u6211\u4eec\u63d0\u4f9b\u4e86\u4e00\u7ec4\u64cd\u4f5c fd_set \u7684\u5b8f\u3002<\/p>\n<h3>7.1 FD_ZERO&#xff1a;\u6e05\u7a7a\u96c6\u5408<\/h3>\n<p>\u51fd\u6570\u5f62\u5f0f&#xff1a;<\/p>\n<p><span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span>fd_set <span class=\"token operator\">*<\/span>set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u4f5c\u7528&#xff1a;<\/p>\n<p>\u5c06\u96c6\u5408\u4e2d\u7684\u6240\u6709\u4f4d\u6e05\u96f6\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>fd_set readfds<span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u6b64\u65f6&#xff1a;<\/p>\n<p>readfds\u4e2d\u6ca1\u6709\u4efb\u4f55\u63cf\u8ff0\u7b26\u88ab\u8bbe\u7f6e<\/p>\n<p>\u75288\u4f4d\u793a\u610f&#xff1a;<\/p>\n<p>00000000<\/p>\n<h3>7.2 FD_SET&#xff1a;\u6dfb\u52a0\u63cf\u8ff0\u7b26<\/h3>\n<p>\u5f62\u5f0f&#xff1a;<\/p>\n<p><span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span> fd_set <span class=\"token operator\">*<\/span>set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u4f5c\u7528&#xff1a;<\/p>\n<p>\u5c06\u6307\u5b9a\u6587\u4ef6\u63cf\u8ff0\u7b26\u52a0\u5165\u96c6\u5408\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p><span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">3<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>\u76d1\u89c6fd3<\/p>\n<h3>7.3 FD_CLR&#xff1a;\u5220\u9664\u63cf\u8ff0\u7b26<\/h3>\n<p>\u5f62\u5f0f&#xff1a;<\/p>\n<p><span class=\"token function\">FD_CLR<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span> fd_set <span class=\"token operator\">*<\/span>set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u4f5c\u7528&#xff1a;<\/p>\n<p>\u5c06\u6307\u5b9a\u63cf\u8ff0\u7b26\u4ece\u96c6\u5408\u4e2d\u79fb\u9664\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p><span class=\"token function\">FD_CLR<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">3<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>\u4e0d\u518d\u76d1\u89c6fd3<\/p>\n<h3>7.4 FD_ISSET&#xff1a;\u68c0\u67e5\u63cf\u8ff0\u7b26\u662f\u5426\u5728\u96c6\u5408\u4e2d<\/h3>\n<p>\u5f62\u5f0f&#xff1a;<\/p>\n<p><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span> fd_set <span class=\"token operator\">*<\/span>set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u4f8b\u5982&#xff1a;<\/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><span class=\"token number\">3<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token comment\">\/\/ fd3\u5bf9\u5e94\u7684\u4f4d\u88ab\u8bbe\u7f6e<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u5728select\u8fd4\u56de\u4ee5\u540e&#xff0c;\u53ef\u4ee5\u901a\u8fc7\u5b83\u68c0\u67e5&#xff1a;<\/p>\n<p>fd3\u662f\u5426\u88ab\u62a5\u544a\u4e3a\u5c31\u7eea<\/p>\n<h3>7.5 \u56db\u4e2a\u5b8f\u603b\u7ed3<\/h3>\n<table>\n<tr>\u5b8f\u4f5c\u7528<\/tr>\n<tbody>\n<tr>\n<td>FD_ZERO<\/td>\n<td>\u6e05\u7a7a\u6574\u4e2a\u63cf\u8ff0\u7b26\u96c6\u5408<\/td>\n<\/tr>\n<tr>\n<td>FD_SET<\/td>\n<td>\u5411\u96c6\u5408\u52a0\u5165\u4e00\u4e2afd<\/td>\n<\/tr>\n<tr>\n<td>FD_CLR<\/td>\n<td>\u4ece\u96c6\u5408\u5220\u9664\u4e00\u4e2afd<\/td>\n<\/tr>\n<tr>\n<td>FD_ISSET<\/td>\n<td>\u5224\u65ad\u6307\u5b9afd\u5bf9\u5e94\u7684\u4f4d\u662f\u5426\u88ab\u8bbe\u7f6e<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u8fd9\u56db\u4e2a\u5b8f\u662fselect\u7f16\u7a0b\u4e2d\u5fc5\u987b\u719f\u7ec3\u638c\u63e1\u7684\u57fa\u7840\u63a5\u53e3\u3002<\/p>\n<hr \/>\n<h2>\u516b\u3001\u901a\u8fc7\u4f4d\u56fe\u7406\u89e3select\u7684\u6267\u884c\u8fc7\u7a0b<\/h2>\n<p>\u8fd9\u91cc\u6211\u4eec\u7528\u4e00\u4e2a\u7b80\u5316\u6a21\u578b\u5206\u6790\u3002<\/p>\n<p>\u5047\u8bbe&#xff1a;<\/p>\n<p>fd_set\u53ea\u67098\u4f4d<\/p>\n<p>\u80fd\u591f\u8868\u793a&#xff1a;<\/p>\n<p>fd0&#xff5e;fd7<\/p>\n<p>\u5b9e\u9645\u4e0a&#xff0c;\u771f\u5b9eLinux\u4e2d\u7684 fd_set \u5e76\u4e0d\u662f\u53ea\u6709\u4e00\u4e2a\u5b57\u8282\u3002<\/p>\n<p>\u8fd9\u91cc\u4ec5\u4ec5\u662f\u4e3a\u4e86\u65b9\u4fbf\u624b\u5de5\u7406\u89e3\u3002<\/p>\n<h3>8.1 \u7b2c\u4e00\u6b65&#xff1a;\u521b\u5efa\u5e76\u6e05\u7a7a\u96c6\u5408<\/h3>\n<p>fd_set readfds<span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u6b64\u65f6&#xff1a;<\/p>\n<p>bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0<\/p>\n<p> 0    0    0    0    0    0    0    0<\/p>\n<p>\u53ef\u4ee5\u5199\u6210&#xff1a;<\/p>\n<p>00000000<\/p>\n<h3>8.2 \u7b2c\u4e8c\u6b65&#xff1a;\u52a0\u5165fd5<\/h3>\n<p><span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5c06bit5\u8bbe\u7f6e\u4e3a1\u3002<\/p>\n<p>\u7ed3\u679c&#xff1a;<\/p>\n<p>00100000<\/p>\n<p>\u6ce8\u610f&#xff1a;<\/p>\n<p>\u6211\u4eec\u4ece\u53f3\u5411\u5de6\u7f16\u53f7&#xff0c;\u6700\u53f3\u4fa7\u662fbit0\u3002<\/p>\n<p>\u56e0\u6b64fd5\u5bf9\u5e94&#xff1a;<\/p>\n<p>00100000<\/p>\n<p>\u800c\u4e0d\u662fbit4\u3002<\/p>\n<h3>8.3 \u7b2c\u4e09\u6b65&#xff1a;\u52a0\u5165fd2\u548cfd1<\/h3>\n<p><span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">2<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u6b64\u65f6&#xff1a;<\/p>\n<p>00100110<\/p>\n<p>\u5bf9\u5e94&#xff1a;<\/p>\n<p>fd5 &#061; 1<\/p>\n<p>fd2 &#061; 1<\/p>\n<p>fd1 &#061; 1<\/p>\n<p>\u4e5f\u5c31\u662f\u5f53\u524d\u76d1\u89c6&#xff1a;<\/p>\n<p>fd1<\/p>\n<p>fd2<\/p>\n<p>fd5<\/p>\n<h3>8.4 \u7b2c\u56db\u6b65&#xff1a;\u8c03\u7528select<\/h3>\n<p>\u6700\u5927\u63cf\u8ff0\u7b26&#xff1a;<\/p>\n<p>5<\/p>\n<p>\u56e0\u6b64&#xff1a;<\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><br \/>\n    <span class=\"token number\">6<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token constant\">NULL<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8fd9\u91cc&#xff1a;<\/p>\n<p>nfds &#061; 5 &#043; 1 &#061; 6<\/p>\n<p>select\u5f00\u59cb\u7b49\u5f85\u8fd9\u4e09\u4e2a\u63cf\u8ff0\u7b26\u7684\u53ef\u8bfb\u6761\u4ef6\u3002<\/p>\n<h3>8.5 \u7b2c\u4e94\u6b65&#xff1a;\u5047\u8bbefd1\u548cfd2\u5c31\u7eea<\/h3>\n<p>\u5047\u8bbe&#xff1a;<\/p>\n<p>fd1&#xff1a;\u53ef\u8bfb<\/p>\n<p>fd2&#xff1a;\u53ef\u8bfb<\/p>\n<p>fd5&#xff1a;\u4e0d\u53ef\u8bfb<\/p>\n<p>\u90a3\u4e48select\u8fd4\u56de\u540e&#xff1a;<\/p>\n<p>readfds &#061; 00000110<\/p>\n<p>\u4e3a\u4ec0\u4e48&#xff1f;<\/p>\n<p>\u56e0\u4e3a&#xff1a;<\/p>\n<p>fd1\u5bf9\u5e94\u7684\u4f4d\u4fdd\u7559<\/p>\n<p>fd2\u5bf9\u5e94\u7684\u4f4d\u4fdd\u7559<\/p>\n<p>fd5\u6ca1\u6709\u5c31\u7eea&#xff0c;\u5bf9\u5e94\u7684\u4f4d\u88ab\u6e05\u9664<\/p>\n<p>\u8fd9\u65f6&#xff1a;<\/p>\n<p><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><\/p>\n<p>\u7ed3\u679c\u4e3a\u771f\u3002<\/p>\n<p><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">2<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><\/p>\n<p>\u7ed3\u679c\u4e3a\u771f\u3002<\/p>\n<p>\u800c&#xff1a;<\/p>\n<p><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><\/p>\n<p>\u7ed3\u679c\u4e3a\u5047\u3002<\/p>\n<h3>8.6 \u6700\u7ec8\u8fc7\u7a0b<\/h3>\n<p>\u521d\u59cb\u5316&#xff1a;<\/p>\n<p>00000000<\/p>\n<p>\u52a0\u5165fd5&#xff1a;<\/p>\n<p>00100000<\/p>\n<p>\u52a0\u5165fd2\u3001fd1&#xff1a;<\/p>\n<p>00100110<\/p>\n<p>\u8c03\u7528select&#xff1a;<\/p>\n<p>\u76d1\u89c6fd1\u3001fd2\u3001fd5<\/p>\n<p>fd1\u3001fd2\u5c31\u7eea<\/p>\n<p>select\u8fd4\u56de&#xff1a;<\/p>\n<p>00000110<\/p>\n<p>\u8fd9\u5c31\u662f\u7406\u89e3select\u6267\u884c\u8fc7\u7a0b\u7684\u91cd\u8981\u57fa\u7840\u3002<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/11\/20261106001818-6aed1cca07cdc.png\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\" \/><\/p>\n<hr \/>\n<h2>\u4e5d\u3001select\u4f1a\u4fee\u6539fd_set&#xff1a;\u4e3a\u4ec0\u4e48\u8fd9\u662f\u4e00\u4e2a\u5927\u5751&#xff1f;<\/h2>\n<p>\u524d\u9762\u7684\u4f8b\u5b50\u544a\u8bc9\u6211\u4eec&#xff1a;<\/p>\n<p>\u8c03\u7528select\u4e4b\u524d&#xff1a;<\/p>\n<p>00100110<\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>\u76d1\u89c6fd1\u3001fd2\u3001fd5<\/p>\n<p>\u4f46\u662f\u8c03\u7528select\u4e4b\u540e&#xff1a;<\/p>\n<p>00000110<\/p>\n<p>\u56e0\u4e3a&#xff1a;<\/p>\n<p>fd5\u6ca1\u6709\u5c31\u7eea<\/p>\n<p>\u5bf9\u5e94\u4f4d\u7f6e\u88ab\u6e05\u9664\u4e86\u3002<\/p>\n<p>\u95ee\u9898\u6765\u4e86&#xff1a;<\/p>\n<p>\u5982\u679c\u4e0b\u4e00\u6b21\u8fd8\u60f3\u7ee7\u7eed\u76d1\u89c6fd5&#xff0c;\u8be5\u600e\u4e48\u529e&#xff1f;<\/p>\n<h3>9.1 \u9519\u8bef\u5199\u6cd5<\/h3>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>fd_set readfds<span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">2<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<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><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">6<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">,<\/span> <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ \u5904\u7406\u5c31\u7eea\u4e8b\u4ef6<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u4e3a\u4ec0\u4e48\u53ef\u80fd\u51fa\u9519&#xff1f;<\/p>\n<p>\u56e0\u4e3a&#xff1a;<\/p>\n<p>select\u4f1a\u4fee\u6539readfds<\/p>\n<p>\u7b2c\u4e00\u6b21\u8c03\u7528\u4e4b\u540e&#xff0c;\u5982\u679cfd5\u6ca1\u6709\u5c31\u7eea&#xff0c;\u5b83\u5bf9\u5e94\u7684\u4f4d\u88ab\u6e05\u9664\u3002<\/p>\n<p>\u4e0b\u4e00\u8f6e\u53c8\u76f4\u63a5\u4f7f\u7528\u4fee\u6539\u540e\u7684&#xff1a;<\/p>\n<p>readfds<\/p>\n<p>\u90a3\u4e48fd5\u5c31\u4e0d\u518d\u88ab\u76d1\u89c6\u4e86\u3002<\/p>\n<h3>9.2 \u6b63\u786e\u601d\u8def\u4e00&#xff1a;\u6bcf\u8f6e\u91cd\u65b0\u8bbe\u7f6e<\/h3>\n<p>\u4f8b\u5982&#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><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    fd_set readfds<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">2<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">int<\/span> ret <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><br \/>\n        <span class=\"token number\">6<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token constant\">NULL<\/span><br \/>\n    <span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ \u68c0\u67e5\u8fd4\u56de\u7ed3\u679c<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u8fd9\u6837\u6bcf\u4e00\u8f6e\u90fd\u91cd\u65b0\u6784\u9020&#xff1a;<\/p>\n<p>\u9700\u8981\u76d1\u89c6\u7684\u63cf\u8ff0\u7b26\u96c6\u5408<\/p>\n<h3>9.3 \u6b63\u786e\u601d\u8def\u4e8c&#xff1a;\u4fdd\u5b58\u4e3b\u96c6\u5408<\/h3>\n<p>\u66f4\u9002\u5408\u670d\u52a1\u5668\u7684\u65b9\u5f0f\u662f\u7ef4\u62a4\u4e24\u5957\u96c6\u5408\u3002<\/p>\n<p>\u4e3b\u96c6\u5408master&#xff1a;<\/p>\n<p>\u4fdd\u5b58\u6240\u6709\u9700\u8981\u957f\u671f\u76d1\u89c6\u7684\u63cf\u8ff0\u7b26<\/p>\n<p>\u4e34\u65f6\u96c6\u5408temp&#xff1a;<\/p>\n<p>\u4ea4\u7ed9select\u4f7f\u7528<\/p>\n<p>\u6bcf\u6b21\u8c03\u7528\u4e4b\u524d&#xff1a;<\/p>\n<p>fd_set temp <span class=\"token operator\">&#061;<\/span> master<span class=\"token punctuation\">;<\/span><\/p>\n<p>\u7136\u540e&#xff1a;<\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span>maxfd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>temp<span class=\"token punctuation\">,<\/span> <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5373\u4f7fselect\u4fee\u6539\u4e86&#xff1a;<\/p>\n<p>temp<\/p>\n<p>\u4e5f\u4e0d\u4f1a\u6539\u53d8&#xff1a;<\/p>\n<p>master<\/p>\n<h3>9.4 \u4e3a\u4ec0\u4e48\u8fd9\u4e2a\u8bbe\u8ba1\u5f88\u91cd\u8981&#xff1f;<\/h3>\n<p>\u56e0\u4e3a\u670d\u52a1\u5668\u8fd0\u884c\u8fc7\u7a0b\u4e2d\u4e0d\u65ad\u6709\u5ba2\u6237\u7aef&#xff1a;<\/p>\n<p>\u5efa\u7acb\u8fde\u63a5<\/p>\n<p>\u65ad\u5f00\u8fde\u63a5<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>\u5ba2\u6237\u7aefA\u8fde\u63a5 \u2192 \u52a0\u5165\u4e3b\u96c6\u5408<\/p>\n<p>\u5ba2\u6237\u7aefB\u8fde\u63a5 \u2192 \u52a0\u5165\u4e3b\u96c6\u5408<\/p>\n<p>\u5ba2\u6237\u7aefA\u65ad\u5f00 \u2192 \u4ece\u4e3b\u96c6\u5408\u5220\u9664<\/p>\n<p>\u7136\u540e\u6bcf\u6b21&#xff1a;<\/p>\n<p>\u4ece\u4e3b\u96c6\u5408\u590d\u5236\u51fa\u4e34\u65f6\u96c6\u5408<\/p>\n<p>\u8ba9select\u5904\u7406\u3002<\/p>\n<p>\u8fd9\u79cd\u8bbe\u8ba1\u53ef\u4ee5\u907f\u514d\u53cd\u590d\u4e22\u5931\u9700\u8981\u76d1\u89c6\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26\u3002<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/11\/20261106001819-6aed1ccbb9573.png\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\" \/><\/p>\n<hr \/>\n<h2>\u5341\u3001select\u7684\u8fd4\u56de\u503c<\/h2>\n<p>select\u8fd4\u56de&#xff1a;<\/p>\n<p><span class=\"token keyword\">int<\/span> ret<span class=\"token punctuation\">;<\/span><\/p>\n<p>\u901a\u5e38\u6709\u4e09\u79cd\u60c5\u51b5\u3002<\/p>\n<h3>10.1 \u8fd4\u56de\u6b63\u6570<\/h3>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>ret <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">2<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8868\u793a\u6709\u76f8\u5e94\u7684\u5c31\u7eea\u6761\u4ef6\u88ab\u62a5\u544a\u3002<\/p>\n<p>\u5982\u679c\u6211\u4eec\u53ea\u4f7f\u7528&#xff1a;<\/p>\n<p>readfds<\/p>\n<p>\u90a3\u4e48\u901a\u5e38\u53ef\u4ee5\u7406\u89e3\u4e3a&#xff1a;<\/p>\n<p>\u67092\u4e2a\u63cf\u8ff0\u7b26\u88ab\u62a5\u544a\u4e3a\u53ef\u8bfb<\/p>\n<p>\u5982\u679c\u540c\u65f6\u4f7f\u7528\u8bfb\u96c6\u5408\u548c\u5199\u96c6\u5408&#xff0c;\u540c\u4e00\u4e2afd\u53ef\u80fd\u5728\u4e0d\u540c\u96c6\u5408\u4e2d\u5206\u522b\u8ba1\u5165\u5c31\u7eea\u6761\u4ef6\u3002<\/p>\n<p>\u56e0\u6b64\u4e0d\u80fd\u5728\u6240\u6709\u60c5\u51b5\u4e0b\u628a\u8fd4\u56de\u503c\u7b80\u5355\u7406\u89e3\u4e3a\u201c\u4e0d\u540c\u6587\u4ef6\u63cf\u8ff0\u7b26\u7684\u6570\u91cf\u201d\u3002<\/p>\n<h3>10.2 \u8fd4\u56de0<\/h3>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>ret <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>\u5728\u6307\u5b9a\u7b49\u5f85\u65f6\u95f4\u5185&#xff0c;\u6ca1\u6709\u76f8\u5e94\u5c31\u7eea\u6761\u4ef6\u6ee1\u8db3&#xff0c;select\u8d85\u65f6\u8fd4\u56de\u3002<\/p>\n<p>\u9700\u8981\u6ce8\u610f&#xff1a;<\/p>\n<p>\u5982\u679c&#xff1a;<\/p>\n<p>timeout <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token constant\">NULL<\/span><\/p>\n<p>\u8868\u793a\u6ca1\u6709\u6307\u5b9a\u8d85\u65f6\u671f\u9650\u3002<\/p>\n<p>\u8fd9\u65f6\u6b63\u5e38\u60c5\u51b5\u4e0b\u4e0d\u4f1a\u56e0\u4e3a\u201c\u7b49\u5f85\u65f6\u95f4\u5230\u4e86\u201d\u800c\u8fd4\u56de0\u3002<\/p>\n<h3>10.3 \u8fd4\u56de-1<\/h3>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>ret <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><\/p>\n<p>\u8868\u793a\u8c03\u7528\u5931\u8d25\u3002<\/p>\n<p>\u53ef\u4ee5\u901a\u8fc7&#xff1a;<\/p>\n<p>errno<\/p>\n<p>\u5224\u65ad\u9519\u8bef\u539f\u56e0\u3002<\/p>\n<p>\u5e38\u89c1\u9519\u8bef\u5305\u62ec&#xff1a;<\/p>\n<table>\n<tr>\u9519\u8bef\u7801\u542b\u4e49<\/tr>\n<tbody>\n<tr>\n<td>EBADF<\/td>\n<td>\u5b58\u5728\u65e0\u6548\u7684\u88ab\u68c0\u67e5\u63cf\u8ff0\u7b26<\/td>\n<\/tr>\n<tr>\n<td>EINTR<\/td>\n<td>\u8c03\u7528\u88ab\u4fe1\u53f7\u4e2d\u65ad<\/td>\n<\/tr>\n<tr>\n<td>EINVAL<\/td>\n<td>\u53c2\u6570\u4e0d\u5408\u6cd5&#xff0c;\u4f8b\u5982nfds\u4e3a\u8d1f<\/td>\n<\/tr>\n<tr>\n<td>ENOMEM<\/td>\n<td>\u5185\u6838\u5185\u5b58\u8d44\u6e90\u4e0d\u8db3<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>10.4 \u4e3a\u4ec0\u4e48\u9700\u8981\u5904\u7406EINTR&#xff1f;<\/h3>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p><span class=\"token keyword\">int<\/span> ret <span class=\"token operator\">&#061;<\/span> <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>\u6267\u884c\u671f\u95f4\u6536\u5230\u4fe1\u53f7\u3002<\/p>\n<p>select\u53ef\u80fd\u8fd4\u56de&#xff1a;<\/p>\n<p>-1<\/p>\n<p>\u5e76\u8bbe\u7f6e&#xff1a;<\/p>\n<p>errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<\/p>\n<p>\u8fd9\u79cd\u60c5\u51b5\u53ef\u4ee5\u6839\u636e\u7a0b\u5e8f\u903b\u8f91\u91cd\u65b0\u7b49\u5f85\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p><span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>ret <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<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><br \/>\n    <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 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>\u4e0d\u8fc7\u91cd\u65b0\u8c03\u7528\u65f6&#xff0c;\u9700\u8981\u91cd\u65b0\u51c6\u5907\u8f93\u5165\u63cf\u8ff0\u7b26\u96c6\u5408\u548c\u9002\u5f53\u7684timeout\u3002<\/p>\n<hr \/>\n<h2>\u5341\u4e00\u3001Socket\u4ec0\u4e48\u65f6\u5019\u7b97\u8bfb\u5c31\u7eea&#xff1f;<\/h2>\n<p>\u73b0\u5728\u8fdb\u5165select\u771f\u6b63\u91cd\u8981\u7684\u90e8\u5206&#xff1a;<\/p>\n<p>\u4ec0\u4e48\u53eb\u6587\u4ef6\u63cf\u8ff0\u7b26\u5c31\u7eea&#xff1f;<\/p>\n<p>\u5bf9\u4e8eSocket&#xff0c;\u6211\u4eec\u4e3b\u8981\u8ba8\u8bba&#xff1a;<\/p>\n<p>\u8bfb\u5c31\u7eea<\/p>\n<p>\u5199\u5c31\u7eea<\/p>\n<h3>11.1 \u7b2c\u4e00\u79cd&#xff1a;\u63a5\u6536\u7f13\u51b2\u533a\u4e2d\u6709\u53ef\u8bfb\u53d6\u6570\u636e<\/h3>\n<p>\u5047\u8bbe\u5ba2\u6237\u7aef\u53d1\u9001&#xff1a;<\/p>\n<p>hello<\/p>\n<p>\u670d\u52a1\u5668\u5185\u6838\u6536\u5230\u6570\u636e\u3002<\/p>\n<p>\u5f53\u63a5\u6536\u7f13\u51b2\u533a\u6ee1\u8db3\u76f8\u5e94\u53ef\u8bfb\u4f4e\u6c34\u4f4d\u7b49\u6761\u4ef6\u65f6&#xff1a;<\/p>\n<p>Socket\u53ef\u8bfb<\/p>\n<p>\u6b64\u65f6select\u53ef\u4ee5\u62a5\u544a&#xff1a;<\/p>\n<p>\u8bfb\u5c31\u7eea<\/p>\n<p>\u5e94\u7528\u7a0b\u5e8f\u968f\u540e\u8c03\u7528&#xff1a;<\/p>\n<p><span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>sockfd<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><\/p>\n<p>\u5373\u53ef\u5c1d\u8bd5\u8bfb\u53d6\u6570\u636e\u3002<\/p>\n<h3>11.2 \u7b2c\u4e8c\u79cd&#xff1a;TCP\u5bf9\u7aef\u5173\u95ed\u8fde\u63a5<\/h3>\n<p>\u5047\u8bbe\u5ba2\u6237\u7aef\u5df2\u7ecf\u6b63\u5e38\u5173\u95ed\u4e86\u53d1\u9001\u65b9\u5411\u3002<\/p>\n<p>\u90a3\u4e48\u670d\u52a1\u5668\u53ef\u80fd\u89c2\u5bdf\u5230&#xff1a;<\/p>\n<p>Socket\u8bfb\u5c31\u7eea<\/p>\n<p>\u4f46\u968f\u540e\u6267\u884c&#xff1a;<\/p>\n<p><span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>sockfd<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><\/p>\n<p>\u8fd4\u56de&#xff1a;<\/p>\n<p>0<\/p>\n<p>\u4e3a\u4ec0\u4e48&#xff1f;<\/p>\n<p>\u56e0\u4e3a&#xff1a;<\/p>\n<p>TCP\u5bf9\u7aef\u5df2\u7ecf\u6b63\u5e38\u7ed3\u675f\u53d1\u9001<\/p>\n<p>\u6b64\u65f6\u8bfb\u53d6\u5230\u4e86EOF\u3002<\/p>\n<p>\u6240\u4ee5\u4e00\u5b9a\u8981\u8bb0\u4f4f&#xff1a;<\/p>\n<p>\u8bfb\u5c31\u7eea\u4e0d\u4ee3\u8868recv\u4e00\u5b9a\u8fd4\u56de\u6b63\u6570\u3002<\/p>\n<p>\u5b83\u4e5f\u53ef\u80fd\u610f\u5473\u7740&#xff1a;<\/p>\n<p>\u8bfb\u53d6\u5c06\u8fd4\u56de0<\/p>\n<h3>11.3 \u7b2c\u4e09\u79cd&#xff1a;\u76d1\u542cSocket\u5b58\u5728\u5f85\u63a5\u53d7\u8fde\u63a5<\/h3>\n<p>\u5047\u8bbe\u670d\u52a1\u5668\u6267\u884c&#xff1a;<\/p>\n<p><span class=\"token function\">listen<\/span><span class=\"token punctuation\">(<\/span>listenfd<span class=\"token punctuation\">,<\/span> <span class=\"token number\">16<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u4e4b\u540e\u6709\u5ba2\u6237\u7aef\u53d1\u8d77\u8fde\u63a5\u3002<\/p>\n<p>\u5f53\u6709\u8fde\u63a5\u8fdb\u5165\u7b49\u5f85\u63a5\u53d7\u7684\u961f\u5217\u5e76\u6ee1\u8db3\u6761\u4ef6\u65f6&#xff1a;<\/p>\n<p>listenfd\u53ef\u8bfb<\/p>\n<p>\u4e8e\u662fselect\u53ef\u4ee5\u62a5\u544a&#xff1a;<\/p>\n<p>\u76d1\u542cSocket\u8bfb\u5c31\u7eea<\/p>\n<p>\u4f46\u8fd9\u91cc\u4e0d\u80fd\u8c03\u7528&#xff1a;<\/p>\n<p><span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>listenfd<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>\u56e0\u4e3a\u76d1\u542cSocket\u4e0d\u662f\u7528\u4e8e\u63a5\u6536\u67d0\u4e2a\u5df2\u8fde\u63a5\u5ba2\u6237\u7aef\u4e1a\u52a1\u6570\u636e\u7684Socket\u3002<\/p>\n<p>\u5e94\u8be5\u8c03\u7528&#xff1a;<\/p>\n<p><span class=\"token function\">accept<\/span><span class=\"token punctuation\">(<\/span>listenfd<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>\u83b7\u5f97\u65b0\u7684\u8fde\u63a5\u63cf\u8ff0\u7b26\u3002<\/p>\n<h3>11.4 \u7b2c\u56db\u79cd&#xff1a;Socket\u5b58\u5728\u5f85\u5904\u7406\u9519\u8bef<\/h3>\n<p>\u67d0\u4e9bSocket\u9519\u8bef\u4e5f\u53ef\u80fd\u4f7f\u76f8\u5e94\u63cf\u8ff0\u7b26\u88ab\u62a5\u544a\u4e3a\u53ef\u8bfb\u3002<\/p>\n<p>\u4e4b\u540e\u8fdb\u884c\u8bfb\u53d6\u6216\u68c0\u67e5\u9519\u8bef\u72b6\u6001\u65f6&#xff0c;\u624d\u80fd\u77e5\u9053\u5177\u4f53\u60c5\u51b5\u3002<\/p>\n<p>\u6240\u4ee5&#xff1a;<\/p>\n<p>\u8bfb\u5c31\u7eea\u53ea\u8868\u793a\u6ee1\u8db3\u4e86\u76f8\u5e94\u8bfb\u53d6\u76f8\u5173\u6761\u4ef6&#xff0c;\u4e0d\u4fdd\u8bc1\u4e00\u5b9a\u83b7\u5f97\u6b63\u5e38\u4e1a\u52a1\u6570\u636e\u3002<\/p>\n<hr \/>\n<h2>\u5341\u4e8c\u3001Socket\u4ec0\u4e48\u65f6\u5019\u7b97\u5199\u5c31\u7eea&#xff1f;<\/h2>\n<p>\u5199\u5c31\u7eea\u540c\u6837\u975e\u5e38\u91cd\u8981\u3002<\/p>\n<h3>12.1 \u53d1\u9001\u7f13\u51b2\u533a\u5177\u6709\u53ef\u7528\u7a7a\u95f4<\/h3>\n<p>TCP Socket\u5185\u90e8\u5177\u6709\u53d1\u9001\u7f13\u51b2\u533a\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>Socket\u53d1\u9001\u7f13\u51b2\u533a<\/p>\n<p>&#043;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;-&#043;<br \/>\n| \u5df2\u4f7f\u7528\u6570\u636e | \u5269\u4f59\u53ef\u7528\u7a7a\u95f4     |<br \/>\n&#043;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;-&#043;<\/p>\n<p>\u5f53\u53ef\u7528\u7a7a\u95f4\u6ee1\u8db3\u76f8\u5e94\u5199\u5165\u4f4e\u6c34\u4f4d\u7b49\u6761\u4ef6\u65f6&#xff1a;<\/p>\n<p>Socket\u53ef\u4ee5\u62a5\u544a\u5199\u5c31\u7eea<\/p>\n<p>\u5e94\u7528\u7a0b\u5e8f\u53ef\u4ee5\u5c1d\u8bd5\u6267\u884c&#xff1a;<\/p>\n<p><span class=\"token function\">send<\/span><span class=\"token punctuation\">(<\/span>sockfd<span class=\"token punctuation\">,<\/span> buffer<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<h3>12.2 \u5199\u5c31\u7eea\u4e0d\u610f\u5473\u7740\u53ef\u4ee5\u4e00\u6b21\u5199\u5165\u4efb\u610f\u957f\u5ea6<\/h3>\n<p>\u5047\u8bbe&#xff1a;<\/p>\n<p>\u53d1\u9001\u7f13\u51b2\u533a\u5f53\u524d\u8fd8\u67091024\u5b57\u8282\u53ef\u7528\u7a7a\u95f4<\/p>\n<p>\u4f46\u662f\u5e94\u7528\u7a0b\u5e8f\u8bd5\u56fe\u53d1\u9001&#xff1a;<\/p>\n<p>100MB\u6570\u636e<\/p>\n<p>\u90a3\u4e48\u4e0d\u80fd\u4ec5\u51ed&#xff1a;<\/p>\n<p>select\u62a5\u544a\u5199\u5c31\u7eea<\/p>\n<p>\u5c31\u65ad\u8a00\u6574\u4e2a100MB\u90fd\u80fd\u591f\u4e00\u6b21\u5199\u5165\u6210\u529f\u3002<\/p>\n<p>TCP\u53d1\u9001\u64cd\u4f5c\u4ecd\u7136\u9700\u8981\u8003\u8651&#xff1a;<\/p>\n<p>\u90e8\u5206\u5199\u5165<\/p>\n<p>\u7f13\u51b2\u533a\u7a7a\u95f4\u53d8\u5316<\/p>\n<p>\u7cfb\u7edf\u8c03\u7528\u8fd4\u56de\u503c<\/p>\n<p>\u7b49\u95ee\u9898\u3002<\/p>\n<h3>12.3 \u975e\u963b\u585econnect\u5b8c\u6210\u4ee5\u540e<\/h3>\n<p>\u5982\u679c\u4f7f\u7528\u975e\u963b\u585eSocket\u6267\u884c&#xff1a;<\/p>\n<p><span class=\"token function\">connect<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u8fde\u63a5\u5efa\u7acb\u8fc7\u7a0b\u53ef\u80fd\u5c1a\u672a\u5b8c\u6210\u3002<\/p>\n<p>\u5f53Socket\u88ab\u62a5\u544a\u4e3a\u53ef\u5199\u65f6&#xff0c;\u53ef\u80fd\u610f\u5473\u7740&#xff1a;<\/p>\n<p>\u8fde\u63a5\u5efa\u7acb\u6210\u529f<\/p>\n<p>\u4e5f\u53ef\u80fd\u610f\u5473\u7740&#xff1a;<\/p>\n<p>\u8fde\u63a5\u5efa\u7acb\u5931\u8d25<\/p>\n<p>\u6b64\u65f6\u4e0d\u80fd\u4ec5\u51ed\u5199\u5c31\u7eea\u5224\u65ad\u8fde\u63a5\u6210\u529f\u3002<\/p>\n<p>\u901a\u5e38\u8fd8\u9700\u8981&#xff1a;<\/p>\n<p><span class=\"token function\">getsockopt<\/span><span class=\"token punctuation\">(<\/span><br \/>\n    sockfd<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 punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u68c0\u67e5\u8fde\u63a5\u7ed3\u679c\u3002<\/p>\n<h3>12.4 \u5173\u95ed\u5199\u65b9\u5411\u4e0e\u9519\u8bef\u60c5\u51b5<\/h3>\n<p>\u5982\u679c\u8fde\u63a5\u7684\u5199\u65b9\u5411\u88ab\u5173\u95ed&#xff0c;\u6216\u8005\u5bf9\u7aef\u5df2\u7ecf\u4e0d\u518d\u63a5\u6536\u6570\u636e&#xff1a;<\/p>\n<p><span class=\"token function\">send<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u53ef\u80fd\u5931\u8d25\u3002<\/p>\n<p>\u5728\u67d0\u4e9b\u60c5\u51b5\u4e0b&#xff0c;\u8fd8\u53ef\u80fd\u6d89\u53ca&#xff1a;<\/p>\n<p>SIGPIPE<\/p>\n<p>\u4fe1\u53f7\u3002<\/p>\n<p>\u56e0\u6b64&#xff1a;<\/p>\n<p>select\u62a5\u544a\u53ef\u5199&#xff0c;\u4e0d\u610f\u5473\u7740\u4e4b\u540e\u7684send\u4e00\u5b9a\u6210\u529f\u3002<\/p>\n<p>\u5b9e\u9645\u53d1\u9001\u4ecd\u7136\u5fc5\u987b\u68c0\u67e5\u8fd4\u56de\u503c\u3002<\/p>\n<hr \/>\n<h2>\u5341\u4e09\u3001\u5f02\u5e38\u5c31\u7eea\u662f\u4ec0\u4e48&#xff1f;<\/h2>\n<p>select\u8fd8\u652f\u6301&#xff1a;<\/p>\n<p>exceptfds<\/p>\n<p>\u7528\u4e8e\u68c0\u6d4b\u7279\u5b9a\u5f02\u5e38\u6761\u4ef6\u3002<\/p>\n<p>\u4f8b\u5982TCP\u5e26\u5916\u6570\u636e\u76f8\u5173\u7684\u60c5\u51b5\u3002<\/p>\n<p>TCP\u62a5\u5934\u4e2d\u5b58\u5728&#xff1a;<\/p>\n<p>URG<\/p>\n<p>Urgent Pointer<\/p>\n<p>\u7b49\u4e0e\u7d27\u6025\u6570\u636e\u6709\u5173\u7684\u5b57\u6bb5\u3002<\/p>\n<p>\u5728\u67d0\u4e9bSocket\u573a\u666f\u4e2d&#xff0c;\u53ef\u4ee5\u901a\u8fc7\u5f02\u5e38\u6761\u4ef6\u96c6\u5408\u76d1\u89c6\u76f8\u5173\u4e8b\u4ef6\u3002<\/p>\n<p>\u5f53\u524d\u9636\u6bb5\u53ea\u9700\u8981\u5efa\u7acb\u4ee5\u4e0b\u8ba4\u8bc6&#xff1a;<\/p>\n<p>readfds&#xff1a;<\/p>\n<p>\u76d1\u89c6\u53ef\u8bfb\u6761\u4ef6<\/p>\n<p>writefds&#xff1a;<\/p>\n<p>\u76d1\u89c6\u53ef\u5199\u6761\u4ef6<\/p>\n<p>exceptfds&#xff1a;<\/p>\n<p>\u76d1\u89c6\u7279\u5b9a\u5f02\u5e38\u6761\u4ef6&#xff0c;\u4f8b\u5982\u5e26\u5916\u6570\u636e\u76f8\u5173\u72b6\u6001<\/p>\n<p>\u666e\u901aTCP\u670d\u52a1\u7aef\u4e3b\u8981\u5148\u638c\u63e1&#xff1a;<\/p>\n<p>readfds<\/p>\n<p>\u7684\u4f7f\u7528\u3002<\/p>\n<p>\u7b49\u5230\u9700\u8981\u53d1\u9001\u7f13\u51b2\u533a\u7ba1\u7406\u65f6&#xff0c;\u518d\u8fdb\u4e00\u6b65\u4f7f\u7528&#xff1a;<\/p>\n<p>writefds<\/p>\n<hr \/>\n<h2>\u5341\u56db\u3001select\u7684\u7279\u70b9<\/h2>\n<p>\u73b0\u5728\u6211\u4eec\u5df2\u7ecf\u7406\u89e3select\u7684\u57fa\u672c\u5de5\u4f5c\u65b9\u5f0f\u3002<\/p>\n<p>\u63a5\u4e0b\u6765\u5206\u6790\u5b83\u7684\u7279\u70b9\u3002<\/p>\n<h3>14.1 \u53ef\u4ee5\u540c\u65f6\u76d1\u89c6\u591a\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26<\/h3>\n<p>\u8fd9\u662fselect\u6700\u5927\u7684\u4f18\u52bf\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>\u76d1\u542cSocket<\/p>\n<p>\u5ba2\u6237\u7aefA\u7684Socket<\/p>\n<p>\u5ba2\u6237\u7aefB\u7684Socket<\/p>\n<p>\u5ba2\u6237\u7aefC\u7684Socket<\/p>\n<p>\u53ef\u4ee5\u540c\u65f6\u653e\u5165\u4e00\u4e2a\u8bfb\u96c6\u5408\u4e2d\u3002<\/p>\n<p><span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>listenfd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>sockfdA<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>sockfdB<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>sockfdC<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u7136\u540e&#xff1a;<\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span>maxfd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">,<\/span> <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u7edf\u4e00\u7b49\u5f85\u3002<\/p>\n<h3>14.2 select\u5bf9\u63cf\u8ff0\u7b26\u7f16\u53f7\u6709\u4e0a\u9650<\/h3>\n<p>\u5728\u5e38\u89c1Linux C\u5e93\u4e2d&#xff1a;<\/p>\n<p>FD_SETSIZE<\/p>\n<p>\u901a\u5e38\u5b9a\u4e49\u4e3a&#xff1a;<\/p>\n<p>1024<\/p>\n<p>\u56e0\u6b64\u4f20\u7edfselect\u63a5\u53e3\u7684 fd_set \u6709\u56fa\u5b9a\u5bb9\u91cf\u9650\u5236\u3002<\/p>\n<p>\u5fc5\u987b\u6ce8\u610f&#xff1a;<\/p>\n<p>\u8fd9\u4e0d\u662f\u8bf4select\u6700\u591a\u80fd\u591f\u5904\u74061024\u4e2a\u5ba2\u6237\u7aef\u3002<\/p>\n<p>\u56e0\u4e3a&#xff1a;<\/p>\n<p>\u6807\u51c6\u8f93\u5165fd0<\/p>\n<p>\u6807\u51c6\u8f93\u51fafd1<\/p>\n<p>\u6807\u51c6\u9519\u8beffd2<\/p>\n<p>\u76d1\u542cfd<\/p>\n<p>\u5176\u4ed6\u5df2\u6253\u5f00\u6587\u4ef6\u63cf\u8ff0\u7b26<\/p>\n<p>\u90fd\u53ef\u80fd\u5360\u7528\u7f16\u53f7\u3002<\/p>\n<p>\u66f4\u91cd\u8981\u7684\u662f&#xff1a;<\/p>\n<p>select\u9650\u5236\u7684\u662ffd_set\u80fd\u591f\u8868\u793a\u7684\u63cf\u8ff0\u7b26\u7f16\u53f7\u8303\u56f4&#xff0c;\u800c\u4e0d\u662f\u5355\u7eaf\u7684\u8fde\u63a5\u6570\u91cf\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>fd &#061; 1500<\/p>\n<p>\u5373\u4f7f\u5f53\u524d\u53ea\u60f3\u76d1\u89c6\u8fd9\u4e00\u4e2a\u63cf\u8ff0\u7b26&#xff0c;\u5728\u5e38\u89c1 FD_SETSIZE&#061;1024 \u7684\u7528\u6237\u6001\u63a5\u53e3\u4e2d&#xff0c;\u4e5f\u4e0d\u80fd\u5b89\u5168\u5730\u76f4\u63a5\u6267\u884c&#xff1a;<\/p>\n<p><span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">1500<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8fd9\u53ef\u80fd\u9020\u6210\u8d8a\u754c\u4e0e\u672a\u5b9a\u4e49\u884c\u4e3a\u3002<\/p>\n<p>\u4e0d\u540c\u5e73\u53f0\u548c\u5b9e\u73b0\u53ef\u80fd\u5b58\u5728\u5dee\u5f02&#xff0c;\u5b9e\u9645\u7a0b\u5e8f\u5e94\u8be5\u9075\u5b88\u76ee\u6807\u5e73\u53f0\u7684\u63a5\u53e3\u9650\u5236\u3002<\/p>\n<h3>14.3 \u4e3a\u4ec0\u4e48\u8fd8\u9700\u8981\u4fdd\u5b58\u539f\u59cb\u63cf\u8ff0\u7b26\u96c6\u5408&#xff1f;<\/h3>\n<p>\u56e0\u4e3a&#xff1a;<\/p>\n<p>select\u4f1a\u4fee\u6539\u4f20\u5165\u7684fd_set<\/p>\n<p>\u5982\u679c\u6bcf\u6b21\u90fd\u9700\u8981\u91cd\u65b0\u76d1\u89c6\u539f\u6709\u63cf\u8ff0\u7b26&#xff0c;\u5c31\u5fc5\u987b&#xff1a;<\/p>\n<p>\u91cd\u65b0\u6784\u9020\u96c6\u5408<\/p>\n<p>\u6216\u8005&#xff1a;<\/p>\n<p>\u4fdd\u5b58\u4e3b\u96c6\u5408&#xff0c;\u518d\u590d\u5236\u4e34\u65f6\u96c6\u5408<\/p>\n<h3>14.4 \u4e3a\u4ec0\u4e48\u8fd8\u8981\u4fdd\u5b58maxfd&#xff1f;<\/h3>\n<p>\u56e0\u4e3aselect\u9700\u8981&#xff1a;<\/p>\n<p>maxfd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><\/p>\n<p>\u4f5c\u4e3a\u7b2c\u4e00\u4e2a\u53c2\u6570\u3002<\/p>\n<p>\u5047\u8bbe&#xff1a;<\/p>\n<p>\u76d1\u542cfd &#061; 3<\/p>\n<p>\u5ba2\u6237\u7aefA fd &#061; 4<\/p>\n<p>\u5ba2\u6237\u7aefB fd &#061; 5<\/p>\n<p>\u6b64\u65f6&#xff1a;<\/p>\n<p>maxfd &#061; 5<\/p>\n<p>\u6240\u4ee5&#xff1a;<\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">6<\/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>\u5982\u679c\u540e\u6765&#xff1a;<\/p>\n<p>\u5ba2\u6237\u7aefB\u65ad\u5f00<\/p>\n<p>\u5e76\u4e14&#xff1a;<\/p>\n<p>fd5\u88ab\u5220\u9664<\/p>\n<p>\u90a3\u4e48\u6700\u5927\u63cf\u8ff0\u7b26\u5c31\u53ef\u80fd\u53d8\u6210&#xff1a;<\/p>\n<p>4<\/p>\n<p>\u56e0\u6b64\u9700\u8981\u91cd\u65b0\u7ef4\u62a4\u6700\u5927\u503c\u3002<\/p>\n<hr \/>\n<h2>\u5341\u4e94\u3001select\u7684\u7f3a\u70b9<\/h2>\n<p>select\u80fd\u591f\u89e3\u51b3\u7b80\u5355\u8f6e\u8be2\u7684\u95ee\u9898&#xff0c;\u4f46\u5e76\u4e0d\u662f\u5b8c\u7f8e\u7684\u65b9\u6848\u3002<\/p>\n<h3>15.1 \u7f3a\u70b9\u4e00&#xff1a;\u6bcf\u6b21\u90fd\u9700\u8981\u51c6\u5907\u63cf\u8ff0\u7b26\u96c6\u5408<\/h3>\n<p>\u56e0\u4e3aselect\u4f1a\u4fee\u6539&#xff1a;<\/p>\n<p>fd_set<\/p>\n<p>\u6bcf\u6b21\u8c03\u7528\u4e4b\u524d&#xff0c;\u90fd\u9700\u8981\u51c6\u5907\u65b0\u7684\u8f93\u5165\u96c6\u5408\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>fd_set temp <span class=\"token operator\">&#061;<\/span> master<span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8fd9\u4f1a\u589e\u52a0\u4ee3\u7801\u7ba1\u7406\u6210\u672c\u3002<\/p>\n<h3>15.2 \u7f3a\u70b9\u4e8c&#xff1a;\u5b58\u5728\u7528\u6237\u6001\u4e0e\u5185\u6838\u6001\u7684\u6570\u636e\u590d\u5236<\/h3>\n<p>select\u9700\u8981\u5c06\u7528\u6237\u7a0b\u5e8f\u63d0\u4f9b\u7684\u63cf\u8ff0\u7b26\u96c6\u5408\u4ea4\u7ed9\u5185\u6838\u5904\u7406\u3002<\/p>\n<p>\u6bcf\u6b21\u8c03\u7528\u90fd\u6d89\u53ca\u76f8\u5173\u6570\u636e\u4f20\u9012\u3002<\/p>\n<p>\u5f53\u63cf\u8ff0\u7b26\u89c4\u6a21\u6bd4\u8f83\u5927\u65f6&#xff0c;\u4f1a\u4ea7\u751f\u989d\u5916\u5f00\u9500\u3002<\/p>\n<h3>15.3 \u7f3a\u70b9\u4e09&#xff1a;\u5185\u6838\u9700\u8981\u68c0\u67e5\u63cf\u8ff0\u7b26\u96c6\u5408<\/h3>\n<p>\u5185\u6838\u9700\u8981\u68c0\u67e5\u4f20\u5165\u7684\u76f8\u5173\u63cf\u8ff0\u7b26\u548c\u5c31\u7eea\u6761\u4ef6\u3002<\/p>\n<p>\u5f53\u9700\u8981\u76d1\u89c6\u7684\u63cf\u8ff0\u7b26\u6570\u91cf\u8f83\u591a\u65f6&#xff0c;\u68c0\u67e5\u6210\u672c\u53ef\u80fd\u589e\u52a0\u3002<\/p>\n<h3>15.4 \u7f3a\u70b9\u56db&#xff1a;\u5e94\u7528\u7a0b\u5e8f\u9700\u8981\u627e\u51fa\u5c31\u7eea\u63cf\u8ff0\u7b26<\/h3>\n<p>select\u8fd4\u56de\u540e&#xff0c;\u7a0b\u5e8f\u8fd8\u9700\u8981\u6267\u884c&#xff1a;<\/p>\n<p><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u68c0\u67e5\u54ea\u4e9b\u63cf\u8ff0\u7b26\u88ab\u62a5\u544a\u4e3a\u5c31\u7eea\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/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\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> fd <span class=\"token operator\">&lt;&#061;<\/span> maxfd<span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>fd<span class=\"token punctuation\">)<\/span><br \/>\n<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>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><br \/>\n    <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u5904\u7406fd<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u8fd9\u610f\u5473\u7740&#xff1a;<\/p>\n<p>\u5e94\u7528\u7a0b\u5e8f\u4e5f\u53ef\u80fd\u9700\u8981\u626b\u63cf\u8f83\u5927\u7684\u63cf\u8ff0\u7b26\u7f16\u53f7\u8303\u56f4\u3002<\/p>\n<h3>15.5 \u7f3a\u70b9\u4e94&#xff1a;fd_set\u5b58\u5728\u5bb9\u91cf\u9650\u5236<\/h3>\n<p>\u5728\u5e38\u89c1Linux\u7528\u6237\u6001\u63a5\u53e3\u4e2d&#xff0c;FD_SETSIZE \u9650\u5236\u4f7fselect\u96be\u4ee5\u76f4\u63a5\u7ba1\u7406\u975e\u5e38\u5927\u7684\u63cf\u8ff0\u7b26\u7f16\u53f7\u3002<\/p>\n<p>\u56e0\u6b64&#xff0c;\u5f53\u5e76\u53d1\u8fde\u63a5\u6570\u91cf\u8f83\u9ad8\u65f6&#xff0c;select\u5b58\u5728\u660e\u663e\u5c40\u9650\u6027\u3002<\/p>\n<h3>15.6 select\u3001poll\u3001epoll\u7684\u5b66\u4e60\u5173\u7cfb<\/h3>\n<p>select<br \/>\n   |<br \/>\n   v<br \/>\npoll<br \/>\n   |<br \/>\n   v<br \/>\nepoll<\/p>\n<p>\u8fd9\u662f\u5e38\u89c1\u7684\u5b66\u4e60\u987a\u5e8f\u3002<\/p>\n<p>\u540e\u9762\u5b66\u4e60poll\u548cepoll\u65f6&#xff0c;\u4f1a\u8fdb\u4e00\u6b65\u8ba8\u8bba&#xff1a;<\/p>\n<p>\u63a5\u53e3\u7ec4\u7ec7\u65b9\u5f0f<\/p>\n<p>\u76d1\u89c6\u5bf9\u8c61\u7ba1\u7406<\/p>\n<p>\u5c31\u7eea\u4e8b\u4ef6\u83b7\u53d6<\/p>\n<p>\u5927\u89c4\u6a21\u8fde\u63a5\u573a\u666f\u7684\u6027\u80fd\u7279\u70b9<\/p>\n<p>\u672c\u7bc7\u5148\u628aselect\u7406\u89e3\u900f\u5f7b\u3002<\/p>\n<hr \/>\n<h2>\u5341\u516d\u3001\u7b2c\u4e00\u4e2a\u5b9e\u9a8c&#xff1a;\u4f7f\u7528select\u76d1\u542c\u6807\u51c6\u8f93\u5165<\/h2>\n<p>\u73b0\u5728\u6211\u4eec\u5df2\u7ecf\u638c\u63e1\u4e86select\u7684\u57fa\u672c\u63a5\u53e3\u3002<\/p>\n<p>\u63a5\u4e0b\u6765\u7f16\u5199\u4e00\u4e2a\u6700\u7b80\u5355\u7684\u7a0b\u5e8f\u3002<\/p>\n<h3>16.1 \u6574\u4e2a\u6587\u4ef6\u8981\u5b9e\u73b0\u4ec0\u4e48\u529f\u80fd&#xff1f;<\/h3>\n<p>\u6211\u4eec\u5e0c\u671b\u7a0b\u5e8f&#xff1a;<\/p>\n<p>\u542f\u52a8<br \/>\n  |<br \/>\n  v<br \/>\n\u7b49\u5f85\u6807\u51c6\u8f93\u5165<br \/>\n  |<br \/>\n  v<br \/>\n\u7528\u6237\u8f93\u5165\u4e00\u884c\u6587\u5b57<br \/>\n  |<br \/>\n  v<br \/>\nselect\u62a5\u544a\u6807\u51c6\u8f93\u5165\u53ef\u8bfb<br \/>\n  |<br \/>\n  v<br \/>\nread\u8bfb\u53d6\u5185\u5bb9<br \/>\n  |<br \/>\n  v<br \/>\n\u6253\u5370\u8f93\u5165<br \/>\n  |<br \/>\n  v<br \/>\n\u7ee7\u7eed\u4e0b\u4e00\u8f6e\u7b49\u5f85<\/p>\n<p>\u53e6\u5916&#xff0c;\u6211\u4eec\u8fd8\u5e0c\u671b\u589e\u52a0\u4e00\u4e2a&#xff1a;<\/p>\n<p>5\u79d2\u8d85\u65f6<\/p>\n<p>\u5982\u679c5\u79d2\u5185\u6ca1\u6709\u4efb\u4f55\u8f93\u5165&#xff0c;\u5c31\u6253\u5370&#xff1a;<\/p>\n<p>select timeout<\/p>\n<p>\u7136\u540e\u7ee7\u7eed\u7b49\u5f85\u3002<\/p>\n<h3>16.2 \u9700\u8981\u8bbe\u8ba1\u54ea\u4e9b\u63a5\u53e3&#xff1f;<\/h3>\n<p>\u8fd9\u4e2a\u5b9e\u9a8c\u975e\u5e38\u7b80\u5355\u3002<\/p>\n<p>\u53ea\u9700\u8981&#xff1a;<\/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><\/p>\n<p>\u4f7f\u7528&#xff1a;<\/p>\n<p>FD_ZERO<\/p>\n<p>\u6e05\u7a7a\u96c6\u5408\u3002<\/p>\n<p>FD_SET<\/p>\n<p>\u52a0\u5165\u6807\u51c6\u8f93\u5165\u3002<\/p>\n<p>select<\/p>\n<p>\u7b49\u5f85\u5c31\u7eea\u3002<\/p>\n<p>FD_ISSET<\/p>\n<p>\u5224\u65ad\u6807\u51c6\u8f93\u5165\u662f\u5426\u53ef\u8bfb\u3002<\/p>\n<p>read<\/p>\n<p>\u8bfb\u53d6\u6570\u636e\u3002<\/p>\n<h3>16.3 \u6807\u51c6\u8f93\u5165\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26<\/h3>\n<p>Linux\u4e2d&#xff1a;<\/p>\n<p>STDIN_FILENO<\/p>\n<p>\u901a\u5e38\u4e3a&#xff1a;<\/p>\n<p>0<\/p>\n<p>\u56e0\u6b64\u6211\u4eec\u53ea\u9700\u8981\u76d1\u89c6&#xff1a;<\/p>\n<p>fd0<\/p>\n<p>\u6700\u5927\u63cf\u8ff0\u7b26&#xff1a;<\/p>\n<p>0<\/p>\n<p>\u6240\u4ee5&#xff1a;<\/p>\n<p>nfds <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span> <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span><\/p>\n<p>\u8c03\u7528&#xff1a;<\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/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<hr \/>\n<h2>\u5341\u4e03\u3001\u6807\u51c6\u8f93\u5165\u5b9e\u9a8c\u5b8c\u6574\u4ee3\u7801<\/h2>\n<p>\u6587\u4ef6\u540d&#xff1a;<\/p>\n<p>select_stdin.c<\/p>\n<p>\u5b8c\u6574\u5b9e\u73b0&#xff1a;<\/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;stdio.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><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;errno.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><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">void<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><br \/>\n    <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/\/ 1. \u5b9a\u4e49\u9700\u8981\u76d1\u89c6\u7684\u8bfb\u96c6\u5408<\/span><br \/>\n        fd_set readfds<span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ 2. \u6bcf\u8f6e\u91cd\u65b0\u6e05\u7a7a\u96c6\u5408<\/span><br \/>\n        <span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ 3. \u52a0\u5165\u6807\u51c6\u8f93\u5165<\/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>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ 4. \u8bbe\u7f6e5\u79d2\u8d85\u65f6<\/span><br \/>\n        <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">timeval<\/span> timeout<span class=\"token punctuation\">;<\/span><br \/>\n        timeout<span class=\"token punctuation\">.<\/span>tv_sec <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">5<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        timeout<span class=\"token punctuation\">.<\/span>tv_usec <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;&gt; &#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">fflush<\/span><span class=\"token punctuation\">(<\/span><span class=\"token constant\">stdout<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ 5. \u7b49\u5f85\u6807\u51c6\u8f93\u5165\u53ef\u8bfb<\/span><br \/>\n        <span class=\"token keyword\">int<\/span> ret <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><br \/>\n            STDIN_FILENO <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>readfds<span class=\"token punctuation\">,<\/span><br \/>\n            <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span><br \/>\n            <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span><br \/>\n            <span class=\"token operator\">&amp;<\/span>timeout<br \/>\n        <span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ 6. \u5904\u7406select\u9519\u8bef<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>ret <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><br \/>\n        <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><br \/>\n            <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 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\">\/\/ 7. \u8d85\u65f6<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>ret <span class=\"token operator\">&#061;&#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 function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\\\\nselect timeout\\\\n&#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 comment\">\/\/ 8. \u68c0\u67e5\u6807\u51c6\u8f93\u5165\u662f\u5426\u53ef\u8bfb<\/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>STDIN_FILENO<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>readfds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><br \/>\n        <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 class-name\">ssize_t<\/span> n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                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><br \/>\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>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><br \/>\n            <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\\\\ninput: &#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                <span class=\"token function\">fwrite<\/span><span class=\"token punctuation\">(<\/span>buffer<span class=\"token punctuation\">,<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">size_t<\/span><span class=\"token punctuation\">)<\/span>n<span class=\"token punctuation\">,<\/span> <span class=\"token constant\">stdout<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                <span class=\"token function\">fflush<\/span><span class=\"token punctuation\">(<\/span><span class=\"token constant\">stdout<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n            <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><br \/>\n            <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\\\\nEOF, exit.\\\\n&#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 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><br \/>\n            <span class=\"token punctuation\">{<\/span><br \/>\n                <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                <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 keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>17.1 \u7f16\u8bd1<\/h3>\n<p>gcc <span class=\"token parameter variable\">-Wall<\/span> <span class=\"token parameter variable\">-Wextra<\/span> select_stdin.c <span class=\"token parameter variable\">-o<\/span> select_stdin<\/p>\n<h3>17.2 \u8fd0\u884c<\/h3>\n<p>.\/select_stdin<\/p>\n<p>\u53ef\u80fd\u663e\u793a&#xff1a;<\/p>\n<p>&gt;<\/p>\n<p>\u5982\u679c5\u79d2\u5185\u6ca1\u6709\u8f93\u5165&#xff1a;<\/p>\n<p>select timeout<br \/>\n&gt;<\/p>\n<p>\u518d\u6b21\u7b49\u5f855\u79d2&#xff1a;<\/p>\n<p>select timeout<br \/>\n&gt;<\/p>\n<p>\u5982\u679c\u8f93\u5165&#xff1a;<\/p>\n<p>hello<\/p>\n<p>\u5e76\u6309\u56de\u8f66&#xff1a;<\/p>\n<p>input: hello<br \/>\n&gt;<\/p>\n<h3>17.3 \u4e3a\u4ec0\u4e48\u6bcf\u6b21\u5faa\u73af\u90fd\u8c03\u7528FD_ZERO&#xff1f;<\/h3>\n<p>\u56e0\u4e3a&#xff1a;<\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u4f1a\u4fee\u6539\u4f20\u5165\u7684&#xff1a;<\/p>\n<p>readfds<\/p>\n<p>\u6240\u4ee5\u6bcf\u8f6e\u5fc5\u987b\u91cd\u65b0\u6784\u9020&#xff1a;<\/p>\n<p>\u9700\u8981\u76d1\u89c6\u7684\u96c6\u5408<\/p>\n<h3>17.4 \u4e3a\u4ec0\u4e48\u6bcf\u8f6e\u90fd\u91cd\u65b0\u8bbe\u7f6etimeout&#xff1f;<\/h3>\n<p>\u56e0\u4e3a\u5728Linux\u4e2d&#xff0c;select\u53ef\u80fd\u4fee\u6539&#xff1a;<\/p>\n<p>timeout<\/p>\n<p>\u6240\u4ee5\u6bcf\u6b21\u90fd\u91cd\u65b0\u521d\u59cb\u5316&#xff1a;<\/p>\n<p>timeout<span class=\"token punctuation\">.<\/span>tv_sec <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">5<\/span><span class=\"token punctuation\">;<\/span><br \/>\ntimeout<span class=\"token punctuation\">.<\/span>tv_usec <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u80fd\u591f\u4fdd\u8bc1\u6bcf\u4e00\u8f6e\u91cd\u65b0\u7b49\u5f85\u7ea65\u79d2\u3002<\/p>\n<h3>17.5 \u4e3a\u4ec0\u4e48\u9700\u8981fflush(stdout)&#xff1f;<\/h3>\n<p>\u56e0\u4e3a&#xff1a;<\/p>\n<p><span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;&gt; &#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u6ca1\u6709\u6362\u884c\u7b26\u3002<\/p>\n<p>\u5728\u67d0\u4e9b\u8f93\u51fa\u7f13\u51b2\u6761\u4ef6\u4e0b&#xff0c;\u63d0\u793a\u7b26\u53ef\u80fd\u6682\u65f6\u4e0d\u4f1a\u7acb\u5373\u663e\u793a\u3002<\/p>\n<p>\u56e0\u6b64&#xff1a;<\/p>\n<p><span class=\"token function\">fflush<\/span><span class=\"token punctuation\">(<\/span><span class=\"token constant\">stdout<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u7528\u4e8e\u5237\u65b0\u8f93\u51fa\u7f13\u51b2\u533a\u3002<\/p>\n<h3>17.6 \u4e3a\u4ec0\u4e48read\u8fd4\u56de0\u8981\u9000\u51fa&#xff1f;<\/h3>\n<p>\u5bf9\u4e8e\u5f53\u524d\u7ec8\u7aef\u8f93\u5165\u573a\u666f&#xff1a;<\/p>\n<p><span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><\/p>\n<p>\u901a\u5e38\u8868\u793aEOF\u3002<\/p>\n<p>\u5982\u679c\u4e0d\u9000\u51fa&#xff1a;<\/p>\n<p>\u6807\u51c6\u8f93\u5165\u6301\u7eed\u5904\u4e8eEOF\u72b6\u6001<\/p>\n<p>\u7a0b\u5e8f\u53ef\u80fd\u518d\u6b21\u7acb\u5373\u4eceselect\u8fd4\u56de&#xff0c;\u7136\u540e\u53cd\u590d\u8bfb\u53d6\u52300&#xff0c;\u5f62\u6210\u65e0\u610f\u4e49\u5faa\u73af\u3002<\/p>\n<h3>17.7 \u6807\u51c6\u8f93\u5165\u5b9e\u9a8c\u8bf4\u660e\u4e86\u4ec0\u4e48&#xff1f;<\/h3>\n<p>\u8fd9\u91cc\u6211\u4eec\u5b9e\u9645\u4e0a\u5b8c\u6210\u4e86&#xff1a;<\/p>\n<p>\u7528\u6237\u8f93\u5165<br \/>\n    |<br \/>\n    v<br \/>\n\u6807\u51c6\u8f93\u5165\u6ee1\u8db3\u53ef\u8bfb\u6761\u4ef6<br \/>\n    |<br \/>\n    v<br \/>\nselect\u8fd4\u56de<br \/>\n    |<br \/>\n    v<br \/>\nFD_ISSET\u5224\u65ad<br \/>\n    |<br \/>\n    v<br \/>\nread\u8bfb\u53d6\u6570\u636e<\/p>\n<p>\u800c\u4e0d\u662f&#xff1a;<\/p>\n<p>\u7a0b\u5e8f\u4e00\u76f4\u963b\u585e\u5728read\u4e0a<\/p>\n<p>\u867d\u7136select\u672c\u8eab\u4ecd\u7136\u53ef\u80fd\u963b\u585e&#xff0c;\u4f46\u5b83\u4e3a\u540e\u9762\u76d1\u89c6\u591a\u4e2aSocket\u5960\u5b9a\u4e86\u57fa\u7840\u3002<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/11\/20261106001821-6aed1ccd2d54b.png\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\" \/><\/p>\n<hr \/>\n<h2>\u5341\u516b\u3001\u7b2c\u4e8c\u4e2a\u5b9e\u9a8c&#xff1a;\u4f7f\u7528select\u5b9e\u73b0TCP\u5b57\u5178\u670d\u52a1\u5668<\/h2>\n<p>\u524d\u9762\u6211\u4eec\u53ea\u76d1\u89c6&#xff1a;<\/p>\n<p>\u6807\u51c6\u8f93\u5165fd0<\/p>\n<p>\u8fd9\u8fd8\u6ca1\u6709\u5b8c\u5168\u4f53\u73b0\u591a\u8def\u8f6c\u63a5\u7684\u4ef7\u503c\u3002<\/p>\n<p>\u63a5\u4e0b\u6765\u5b9e\u73b0\u4e00\u4e2a&#xff1a;<\/p>\n<p>\u540c\u65f6\u5904\u7406\u591a\u4e2aTCP\u5ba2\u6237\u7aef\u7684\u5b57\u5178\u670d\u52a1\u5668\u3002<\/p>\n<h3>18.1 \u670d\u52a1\u5668\u9700\u8981\u5b9e\u73b0\u4ec0\u4e48\u529f\u80fd&#xff1f;<\/h3>\n<p>\u5047\u8bbe\u5ba2\u6237\u7aef\u8f93\u5165&#xff1a;<\/p>\n<p>hello<\/p>\n<p>\u670d\u52a1\u5668\u8fd4\u56de&#xff1a;<\/p>\n<p>\u4f60\u597d<\/p>\n<p>\u5ba2\u6237\u7aef\u8f93\u5165&#xff1a;<\/p>\n<p>apple<\/p>\n<p>\u670d\u52a1\u5668\u8fd4\u56de&#xff1a;<\/p>\n<p>\u82f9\u679c<\/p>\n<p>\u5ba2\u6237\u7aef\u8f93\u5165&#xff1a;<\/p>\n<p>linux<\/p>\n<p>\u670d\u52a1\u5668\u8fd4\u56de&#xff1a;<\/p>\n<p>Linux\u64cd\u4f5c\u7cfb\u7edf<\/p>\n<p>\u5982\u679c\u8f93\u5165\u672a\u77e5\u5355\u8bcd&#xff1a;<\/p>\n<p>unknown<\/p>\n<p>\u670d\u52a1\u5668\u8fd4\u56de&#xff1a;<\/p>\n<p>not found<\/p>\n<p>\u6211\u4eec\u7684\u91cd\u70b9\u4e0d\u662f\u5b57\u5178\u67e5\u8be2\u672c\u8eab\u3002<\/p>\n<p>\u800c\u662f&#xff1a;<\/p>\n<p>\u8ba9\u4e00\u4e2a\u670d\u52a1\u5668\u7ebf\u7a0b\u901a\u8fc7select\u7ba1\u7406\u591a\u4e2aTCP\u8fde\u63a5\u3002<\/p>\n<h3>18.3 \u76d1\u542cSocket\u4e0e\u901a\u4fe1Socket\u6709\u4ec0\u4e48\u533a\u522b&#xff1f;<\/h3>\n<p>\u5bf9\u4e8eTCP\u670d\u52a1\u5668&#xff1a;<\/p>\n<p>listenfd<\/p>\n<p>\u8d1f\u8d23&#xff1a;<\/p>\n<p>\u76d1\u542c\u65b0\u7684\u8fde\u63a5\u8bf7\u6c42<\/p>\n<p>\u5f53\u5b83\u8bfb\u5c31\u7eea\u65f6&#xff0c;\u901a\u5e38\u6267\u884c&#xff1a;<\/p>\n<p><span class=\"token function\">accept<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u83b7\u5f97&#xff1a;<\/p>\n<p>clientfd<\/p>\n<p>\u800c&#xff1a;<\/p>\n<p>clientfd<\/p>\n<p>\u8d1f\u8d23&#xff1a;<\/p>\n<p>\u63a5\u6536\u5177\u4f53\u5ba2\u6237\u7aef\u53d1\u9001\u7684\u6570\u636e<\/p>\n<p>\u5f53\u5b83\u8bfb\u5c31\u7eea\u65f6&#xff0c;\u901a\u5e38\u6267\u884c&#xff1a;<\/p>\n<p><span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u6240\u4ee5\u670d\u52a1\u5668\u5fc5\u987b\u533a\u5206&#xff1a;<\/p>\n<p>listenfd\u8bfb\u5c31\u7eea \u2192 accept<\/p>\n<p>\u548c&#xff1a;<\/p>\n<p>clientfd\u8bfb\u5c31\u7eea \u2192 recv<\/p>\n<p>\u8fd9\u4e5f\u662fselect\u670d\u52a1\u5668\u4e8b\u4ef6\u5faa\u73af\u7684\u6838\u5fc3\u3002<\/p>\n<hr \/>\n<h2>\u5341\u4e5d\u3001\u5148\u8bbe\u8ba1\u670d\u52a1\u5668\u6587\u4ef6\u4e0e\u63a5\u53e3<\/h2>\n<p>\u4e3a\u4e86\u8ba9\u6574\u4e2a\u7a0b\u5e8f\u7ed3\u6784\u6e05\u6670&#xff0c;\u6211\u4eec\u4f7f\u7528\u4e24\u4e2a\u6587\u4ef6\u3002<\/p>\n<p>select-server\/<br \/>\n\u2502<br \/>\n\u251c\u2500\u2500 select_server.hpp<br \/>\n\u2502<br \/>\n\u2514\u2500\u2500 dict_server.cpp<\/p>\n<p>\u5176\u4e2d&#xff1a;<\/p>\n<p>select_server.hpp<\/p>\n<p>\u8d1f\u8d23&#xff1a;<\/p>\n<p>Selector\u63cf\u8ff0\u7b26\u7ba1\u7406<\/p>\n<p>TcpSelectServer\u7f51\u7edc\u670d\u52a1<\/p>\n<p>\u8fde\u63a5\u5efa\u7acb<\/p>\n<p>\u8fde\u63a5\u5173\u95ed<\/p>\n<p>\u6570\u636e\u8bfb\u53d6\u4e0e\u54cd\u5e94\u53d1\u9001<\/p>\n<p>\u800c&#xff1a;<\/p>\n<p>dict_server.cpp<\/p>\n<p>\u8d1f\u8d23&#xff1a;<\/p>\n<p>\u5b9a\u4e49\u5b57\u5178\u5185\u5bb9<\/p>\n<p>\u5b9e\u73b0\u4e1a\u52a1\u5904\u7406\u51fd\u6570<\/p>\n<p>\u521b\u5efa\u670d\u52a1\u5668\u5bf9\u8c61<\/p>\n<p>\u542f\u52a8\u670d\u52a1<\/p>\n<p>\u8fd9\u6837\u7684\u8bbe\u8ba1\u8ba9&#xff1a;<\/p>\n<p>\u7f51\u7edc\u5904\u7406\u903b\u8f91<\/p>\n<p>\u548c&#xff1a;<\/p>\n<p>\u4e1a\u52a1\u903b\u8f91<\/p>\n<p>\u5206\u5f00\u3002<\/p>\n<h3>19.1 \u4e3a\u4ec0\u4e48\u9700\u8981Selector\u7c7b&#xff1f;<\/h3>\n<p>\u56e0\u4e3a\u5982\u679c\u6bcf\u6b21\u5728TCP\u670d\u52a1\u5668\u4e2d\u624b\u52a8\u7ef4\u62a4&#xff1a;<\/p>\n<p>FD_SET<\/p>\n<p>FD_CLR<\/p>\n<p>FD_ISSET<\/p>\n<p>\u4ee5\u53ca&#xff1a;<\/p>\n<p>maxfd<\/p>\n<p>\u4f1a\u4f7f\u670d\u52a1\u5668\u903b\u8f91\u6bd4\u8f83\u6df7\u4e71\u3002<\/p>\n<p>\u56e0\u6b64&#xff0c;\u6211\u4eec\u8bbe\u8ba1&#xff1a;<\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Selector<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u4e13\u95e8\u7ba1\u7406select\u76f8\u5173\u64cd\u4f5c\u3002<\/p>\n<h3>19.2 Selector\u9700\u8981\u63d0\u4f9b\u4ec0\u4e48\u63a5\u53e3&#xff1f;<\/h3>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Selector<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">public<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token keyword\">bool<\/span> <span class=\"token function\">Add<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">void<\/span> <span class=\"token function\">Del<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">int<\/span> <span class=\"token function\">Wait<\/span><span class=\"token punctuation\">(<\/span>std<span class=\"token double-colon punctuation\">::<\/span>vector<span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token operator\">&gt;<\/span><span class=\"token operator\">*<\/span> ready<span class=\"token punctuation\">)<\/span><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<p><span class=\"token function\">Add<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u628a\u4e00\u4e2a\u63cf\u8ff0\u7b26\u52a0\u5165\u76d1\u89c6\u96c6\u5408\u3002<\/p>\n<p><span class=\"token function\">Del<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u4ece\u76d1\u89c6\u96c6\u5408\u4e2d\u5220\u9664\u4e00\u4e2a\u63cf\u8ff0\u7b26\u3002<\/p>\n<p><span class=\"token function\">Wait<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u7b49\u5f85\u5c31\u7eea\u4e8b\u4ef6&#xff0c;\u5e76\u628a\u5c31\u7eea\u7684\u63cf\u8ff0\u7b26\u4ea4\u7ed9\u8c03\u7528\u8005\u3002<\/p>\n<h3>19.3 \u4e3a\u4ec0\u4e48Selector\u4e0d\u76f4\u63a5\u7ba1\u7406Socket\u751f\u547d\u5468\u671f&#xff1f;<\/h3>\n<p>\u56e0\u4e3a&#xff1a;<\/p>\n<p>\u76d1\u89c6\u4e00\u4e2afd<\/p>\n<p>\u548c&#xff1a;<\/p>\n<p>\u62e5\u6709\u5e76\u5173\u95ed\u8fd9\u4e2afd<\/p>\n<p>\u662f\u4e24\u79cd\u4e0d\u540c\u7684\u804c\u8d23\u3002<\/p>\n<p>\u5728\u8fd9\u4e2a\u5b9e\u73b0\u4e2d&#xff1a;<\/p>\n<p>Selector\u53ea\u4fdd\u5b58\u6587\u4ef6\u63cf\u8ff0\u7b26\u7f16\u53f7<\/p>\n<p>\u7531&#xff1a;<\/p>\n<p>TcpSelectServer<\/p>\n<p>\u8d1f\u8d23\u5b9e\u9645\u5173\u95ed\u8fde\u63a5\u3002<\/p>\n<p>\u8fd9\u6837\u53ef\u4ee5\u907f\u514d\u591a\u4e2a\u5bf9\u8c61\u540c\u65f6\u8ba4\u4e3a\u81ea\u5df1\u62e5\u6709\u540c\u4e00\u4e2aSocket&#xff0c;\u5bfc\u81f4\u91cd\u590d\u5173\u95ed\u7b49\u95ee\u9898\u3002<\/p>\n<h3>19.4 TcpSelectServer\u9700\u8981\u63d0\u4f9b\u4ec0\u4e48\u63a5\u53e3&#xff1f;<\/h3>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">TcpSelectServer<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">public<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token function\">TcpSelectServer<\/span><span class=\"token punctuation\">(<\/span><br \/>\n        <span class=\"token keyword\">const<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">&amp;<\/span> ip<span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token keyword\">uint16_t<\/span> port<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\">Start<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> Handler<span class=\"token operator\">&amp;<\/span> handler<span class=\"token punctuation\">)<\/span><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<p><span class=\"token function\">Start<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u8d1f\u8d23\u5b8c\u6574\u670d\u52a1\u6d41\u7a0b\u3002<\/p>\n<p>\u9700\u8981\u5b8c\u6210&#xff1a;<\/p>\n<p>\u521b\u5efaSocket<br \/>\n      |<br \/>\n      v<br \/>\n\u7ed1\u5b9aIP\u548c\u7aef\u53e3<br \/>\n      |<br \/>\n      v<br \/>\n\u8fdb\u5165\u76d1\u542c\u72b6\u6001<br \/>\n      |<br \/>\n      v<br \/>\n\u628a\u76d1\u542cfd\u52a0\u5165Selector<br \/>\n      |<br \/>\n      v<br \/>\n\u8fdb\u5165select\u4e8b\u4ef6\u5faa\u73af<br \/>\n      |<br \/>\n      v<br \/>\n\u5904\u7406\u65b0\u8fde\u63a5<br \/>\n      |<br \/>\n      v<br \/>\n\u5904\u7406\u5ba2\u6237\u7aef\u8bf7\u6c42<\/p>\n<h3>19.5 Handler\u662f\u4ec0\u4e48&#xff1f;<\/h3>\n<p>\u4e1a\u52a1\u5904\u7406\u51fd\u6570\u5b9a\u4e49\u4e3a&#xff1a;<\/p>\n<p><span class=\"token keyword\">using<\/span> Handler <span class=\"token operator\">&#061;<\/span> std<span class=\"token double-colon punctuation\">::<\/span>function<span class=\"token operator\">&lt;<\/span><br \/>\n    <span class=\"token keyword\">void<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">&amp;<\/span><span class=\"token punctuation\">,<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">*<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token operator\">&gt;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u53c2\u6570&#xff1a;<\/p>\n<p><span class=\"token keyword\">const<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">&amp;<\/span> req<\/p>\n<p>\u8868\u793a\u5ba2\u6237\u7aef\u8bf7\u6c42\u3002<\/p>\n<p>std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">*<\/span> resp<\/p>\n<p>\u7528\u4e8e\u4fdd\u5b58\u670d\u52a1\u5668\u54cd\u5e94\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p><span class=\"token function\">handler<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;hello&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>resp<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u6700\u540e&#xff1a;<\/p>\n<p>resp &#061; &#034;\u4f60\u597d&#034;<\/p>\n<p>\u901a\u8fc7\u8fd9\u79cd\u65b9\u5f0f&#xff0c;TCP\u670d\u52a1\u5668\u4e0d\u9700\u8981\u5173\u5fc3&#xff1a;<\/p>\n<p>\u5177\u4f53\u67e5\u8be2\u4ec0\u4e48\u5b57\u5178<\/p>\n<p>\u53ea\u8d1f\u8d23&#xff1a;<\/p>\n<p>\u63a5\u6536\u8bf7\u6c42<\/p>\n<p>\u8c03\u7528Handler<\/p>\n<p>\u53d1\u9001\u54cd\u5e94<\/p>\n<hr \/>\n<h2>\u4e8c\u5341\u3001\u4e3a\u4ec0\u4e48TCP\u5b57\u5178\u670d\u52a1\u5668\u8fd8\u9700\u8981\u5904\u7406\u6d88\u606f\u8fb9\u754c&#xff1f;<\/h2>\n<p>\u8fd9\u91cc\u5148\u5904\u7406\u4e00\u4e2a\u91cd\u8981\u95ee\u9898\u3002<\/p>\n<p>\u6211\u4eec\u5df2\u7ecf\u77e5\u9053&#xff1a;<\/p>\n<p>TCP\u662f\u5b57\u8282\u6d41\u534f\u8bae\u3002<\/p>\n<p>\u56e0\u6b64\u5ba2\u6237\u7aef\u6267\u884c&#xff1a;<\/p>\n<p><span class=\"token function\">send<\/span><span class=\"token punctuation\">(<\/span>sockfd<span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;hello&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">5<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u4e0d\u4ee3\u8868\u670d\u52a1\u5668\u6267\u884c\u4e00\u6b21&#xff1a;<\/p>\n<p><span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u5c31\u4e00\u5b9a\u6070\u597d\u5f97\u5230&#xff1a;<\/p>\n<p>hello<\/p>\n<p>\u4f8b\u5982\u670d\u52a1\u5668\u53ef\u80fd\u5206\u522b\u6536\u5230&#xff1a;<\/p>\n<p>hel<\/p>\n<p>\u548c&#xff1a;<\/p>\n<p>lo<\/p>\n<p>\u4e5f\u53ef\u80fd\u4e00\u6b21\u6536\u5230\u591a\u6761\u8bf7\u6c42\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>hello\\\\nworld\\\\n<\/p>\n<p>\u5982\u679c\u76f4\u63a5\u628a\u6bcf\u6b21recv\u5f97\u5230\u7684\u5185\u5bb9\u5f53\u4f5c\u5b8c\u6574\u8bf7\u6c42&#xff0c;\u5c31\u53ef\u80fd\u51fa\u73b0\u89e3\u6790\u9519\u8bef\u3002<\/p>\n<h3>20.1 \u6211\u4eec\u600e\u6837\u89e3\u51b3&#xff1f;<\/h3>\n<p>\u8fd9\u91cc\u4f7f\u7528\u7b80\u5355\u7684&#xff1a;<\/p>\n<p>\u6362\u884c\u7b26\u5206\u9694\u534f\u8bae\u3002<\/p>\n<p>\u89c4\u5b9a&#xff1a;<\/p>\n<p>\u5ba2\u6237\u7aef\u6bcf\u53d1\u9001\u4e00\u4e2a\u5355\u8bcd&#xff0c;\u4ee5\\\\n\u7ed3\u675f<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>hello\\\\n<\/p>\n<p>\u670d\u52a1\u5668\u54cd\u5e94&#xff1a;<\/p>\n<p>\u4f60\u597d\\\\n<\/p>\n<p>\u8fd9\u6837\u670d\u52a1\u5668\u53ef\u4ee5\u5c06\u6536\u5230\u7684TCP\u5b57\u8282\u6d41\u6301\u7eed\u653e\u5165\u7f13\u51b2\u533a\u3002<\/p>\n<p>\u53ea\u6709\u627e\u5230&#xff1a;<\/p>\n<p><span class=\"token char\">&#039;\\\\n&#039;<\/span><\/p>\n<p>\u65f6&#xff0c;\u624d\u8ba4\u4e3a\u4e00\u6761\u8bf7\u6c42\u5b8c\u6574\u3002<\/p>\n<h3>20.2 \u4e3a\u4ec0\u4e48\u6bcf\u4e2a\u5ba2\u6237\u7aef\u90fd\u9700\u8981\u81ea\u5df1\u7684\u63a5\u6536\u7f13\u51b2\u533a&#xff1f;<\/h3>\n<p>\u56e0\u4e3a\u4e0d\u540c\u5ba2\u6237\u7aef\u53ef\u80fd\u5206\u522b\u53d1\u9001&#xff1a;<\/p>\n<p>\u5ba2\u6237\u7aefA&#xff1a;<\/p>\n<p>hel<\/p>\n<p>\u4ee5\u53ca&#xff1a;<\/p>\n<p>\u5ba2\u6237\u7aefB&#xff1a;<\/p>\n<p>app<\/p>\n<p>\u670d\u52a1\u5668\u5fc5\u987b\u5206\u522b\u4fdd\u5b58\u5b83\u4eec\u7684\u672a\u5b8c\u6210\u8bf7\u6c42\u3002<\/p>\n<p>\u4e0d\u80fd\u628a\u6240\u6709\u5ba2\u6237\u7aef\u7684\u6570\u636e\u6df7\u5728\u4e00\u8d77\u3002<\/p>\n<p>\u56e0\u6b64\u5728\u670d\u52a1\u5668\u5185\u90e8\u7ef4\u62a4&#xff1a;<\/p>\n<p>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> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">&gt;<\/span> inputs_<span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5176\u4e2d&#xff1a;<\/p>\n<p>key&#xff1a;\u5ba2\u6237\u7aef\u6587\u4ef6\u63cf\u8ff0\u7b26<\/p>\n<p>value&#xff1a;\u8be5\u5ba2\u6237\u7aef\u5c1a\u672a\u7ec4\u6210\u5b8c\u6574\u8bf7\u6c42\u7684\u6570\u636e<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>fd4 \u2192 &#034;hel&#034;<\/p>\n<p>fd5 \u2192 &#034;app&#034;<\/p>\n<p>\u540e\u7eed\u5982\u679cfd4\u7ee7\u7eed\u6536\u5230&#xff1a;<\/p>\n<p>lo\\\\n<\/p>\n<p>\u5c31\u7ec4\u6210&#xff1a;<\/p>\n<p>hello\\\\n<\/p>\n<p>\u7136\u540e\u53ef\u4ee5\u67e5\u8be2\u5b57\u5178\u3002<\/p>\n<p>\u8fd9\u4e00\u6b65\u867d\u7136\u5c5e\u4e8eTCP\u5e94\u7528\u5c42\u6d88\u606f\u7ec4\u7ec7&#xff0c;\u4f46\u5bf9\u4e8e\u5199\u51fa\u80fd\u591f\u6b63\u786e\u5904\u7406\u8fde\u7eed\u8bf7\u6c42\u7684\u670d\u52a1\u5668\u5f88\u91cd\u8981\u3002<\/p>\n<hr \/>\n<h2>\u4e8c\u5341\u4e00\u3001\u5b8c\u6574\u5b9e\u73b0select_server.hpp<\/h2>\n<p>\u4e0b\u9762\u7ed9\u51fa\u5b8c\u6574\u4ee3\u7801\u3002<\/p>\n<p>\u8fd9\u4e2a\u7248\u672c\u4f7f\u7528\u7cfb\u7edfSocket\u63a5\u53e3\u5b9e\u73b0\u5e95\u5c42\u7f51\u7edc\u64cd\u4f5c&#xff0c;\u4e0d\u4f9d\u8d56\u989d\u5916\u7684TcpSocket\u5c01\u88c5\u6587\u4ef6&#xff0c;\u53ef\u4ee5\u76f4\u63a5\u5728Ubuntu\u4e0a\u7f16\u8bd1\u3002<\/p>\n<p>\u9700\u8981\u8bf4\u660e&#xff1a;<\/p>\n<p>\u672c\u4f8b\u7684\u91cd\u70b9\u662fselect\u7684\u8bfb\u4e8b\u4ef6\u7ba1\u7406\u3002\u4e3a\u4e86\u4fdd\u6301\u4ee3\u7801\u8303\u56f4\u9002\u5408\u521d\u5b66\u8005&#xff0c;\u54cd\u5e94\u53d1\u9001\u4ecd\u91c7\u7528\u963b\u585e\u5f0f send() \u5faa\u73af\u3002<\/p>\n<p>\u56e0\u6b64\u5b83\u662f\u5b8c\u6574\u7684\u6559\u5b66\u793a\u4f8b&#xff0c;\u800c\u4e0d\u662f\u5df2\u7ecf\u89e3\u51b3\u6162\u5ba2\u6237\u7aef\u3001\u65e0\u9650\u8fde\u63a5\u7b49\u5168\u90e8\u95ee\u9898\u7684\u751f\u4ea7\u7ea7\u9ad8\u5e76\u53d1\u670d\u52a1\u5668\u3002<\/p>\n<p>\u6587\u4ef6&#xff1a;<\/p>\n<p>select_server.hpp<\/p>\n<p>\u5b8c\u6574\u5b9e\u73b0&#xff1a;<\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">pragma<\/span> <span class=\"token expression\">once<\/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;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;errno.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;netinet\/in.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;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;cstdint&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;functional&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 comment\">\/\/ \u4e1a\u52a1\u51fd\u6570&#xff1a;\u8f93\u5165\u8bf7\u6c42&#xff0c;\u586b\u5199\u54cd\u5e94<\/span><br \/>\n<span class=\"token keyword\">using<\/span> Handler <span class=\"token operator\">&#061;<\/span> std<span class=\"token double-colon punctuation\">::<\/span>function<span class=\"token operator\">&lt;<\/span><br \/>\n    <span class=\"token keyword\">void<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">&amp;<\/span><span class=\"token punctuation\">,<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">*<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token operator\">&gt;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token comment\">\/\/ &#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;<\/span><br \/>\n<span class=\"token comment\">\/\/ Selector&#xff1a;\u7ba1\u7406select\u8bfb\u96c6\u5408<\/span><br \/>\n<span class=\"token comment\">\/\/ &#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;<\/span><\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Selector<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">public<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token function\">Selector<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">:<\/span> <span class=\"token function\">max_fd_<\/span><span class=\"token punctuation\">(<\/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><br \/>\n        <span class=\"token comment\">\/\/ \u5fc5\u987b\u521d\u59cb\u5316<\/span><br \/>\n        <span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>master_<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ \u6dfb\u52a0\u4e00\u4e2a\u9700\u8981\u76d1\u89c6\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26<\/span><br \/>\n    <span class=\"token keyword\">bool<\/span> <span class=\"token function\">Add<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">)<\/span><br \/>\n    <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u907f\u514d\u8d85\u8fc7fd_set\u652f\u6301\u8303\u56f4<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>fd <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span> <span class=\"token operator\">||<\/span> fd <span class=\"token operator\">&gt;&#061;<\/span> FD_SETSIZE<span class=\"token punctuation\">)<\/span><br \/>\n        <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\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>master_<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>fd <span class=\"token operator\">&gt;<\/span> max_fd_<span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><br \/>\n            max_fd_ <span class=\"token operator\">&#061;<\/span> fd<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 comment\">\/\/ \u5220\u9664\u4e00\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26<\/span><br \/>\n    <span class=\"token keyword\">void<\/span> <span class=\"token function\">Del<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">)<\/span><br \/>\n    <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>fd <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span> <span class=\"token operator\">||<\/span> fd <span class=\"token operator\">&gt;&#061;<\/span> FD_SETSIZE<span class=\"token punctuation\">)<\/span><br \/>\n        <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 function\">FD_CLR<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>master_<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ \u5982\u679c\u5220\u9664\u7684\u662f\u6700\u5927fd&#xff0c;\u9700\u8981\u91cd\u65b0\u8ba1\u7b97<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>fd <span class=\"token operator\">&#061;&#061;<\/span> max_fd_<span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><br \/>\n                max_fd_ <span class=\"token operator\">&gt;&#061;<\/span> <span class=\"token number\">0<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n                <span class=\"token operator\">!<\/span><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span>max_fd_<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>master_<span class=\"token punctuation\">)<\/span><br \/>\n            <span class=\"token punctuation\">)<\/span><br \/>\n            <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token operator\">&#8212;<\/span>max_fd_<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 comment\">\/\/ \u7b49\u5f85\u8bfb\u5c31\u7eea\u4e8b\u4ef6<\/span><br \/>\n    <span class=\"token comment\">\/\/ \u8fd4\u56de-1&#xff1a;\u9519\u8bef<\/span><br \/>\n    <span class=\"token comment\">\/\/ \u8fd4\u56de\u6b63\u6570&#xff1a;\u62a5\u544a\u7684\u5c31\u7eea\u63cf\u8ff0\u7b26\u6570\u91cf<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> <span class=\"token function\">Wait<\/span><span class=\"token punctuation\">(<\/span>std<span class=\"token double-colon punctuation\">::<\/span>vector<span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token operator\">&gt;<\/span><span class=\"token operator\">*<\/span> ready<span class=\"token punctuation\">)<\/span><br \/>\n    <span class=\"token punctuation\">{<\/span><br \/>\n        ready<span class=\"token operator\">-&gt;<\/span><span class=\"token function\">clear<\/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>max_fd_ <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><br \/>\n        <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<p>        <span class=\"token comment\">\/\/ select\u4f1a\u4fee\u6539\u4f20\u5165\u7684fd_set<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u56e0\u6b64\u5fc5\u987b\u4f7f\u7528\u4e34\u65f6\u96c6\u5408<\/span><br \/>\n        fd_set temp <span class=\"token operator\">&#061;<\/span> master_<span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">int<\/span> ret <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><br \/>\n            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>temp<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><br \/>\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>ret <span class=\"token operator\">&lt;&#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 keyword\">return<\/span> ret<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ \u6839\u636e\u8fd4\u56de\u540e\u7684\u4e34\u65f6\u96c6\u5408\u67e5\u627e\u5c31\u7eeafd<\/span><br \/>\n        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> fd <span class=\"token operator\">&lt;&#061;<\/span> max_fd_<span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>fd<span class=\"token punctuation\">)<\/span><br \/>\n        <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>temp<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><br \/>\n            <span class=\"token punctuation\">{<\/span><br \/>\n                ready<span class=\"token operator\">-&gt;<\/span><span class=\"token function\">push_back<\/span><span class=\"token punctuation\">(<\/span>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\">return<\/span> ret<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">private<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token comment\">\/\/ \u4fdd\u5b58\u957f\u671f\u9700\u8981\u76d1\u89c6\u7684\u63cf\u8ff0\u7b26\u96c6\u5408<\/span><br \/>\n    fd_set master_<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ \u5f53\u524d\u6700\u5927\u6587\u4ef6\u63cf\u8ff0\u7b26<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> max_fd_<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token comment\">\/\/ &#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;<\/span><br \/>\n<span class=\"token comment\">\/\/ TcpSelectServer&#xff1a;TCP\u5b57\u5178\u670d\u52a1\u5668<\/span><br \/>\n<span class=\"token comment\">\/\/ &#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;&#061;<\/span><\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">TcpSelectServer<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">public<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token function\">TcpSelectServer<\/span><span class=\"token punctuation\">(<\/span><br \/>\n        <span class=\"token keyword\">const<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">&amp;<\/span> ip<span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token keyword\">uint16_t<\/span> port<br \/>\n    <span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token operator\">:<\/span> <span class=\"token function\">ip_<\/span><span class=\"token punctuation\">(<\/span>ip<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n          <span class=\"token function\">port_<\/span><span class=\"token punctuation\">(<\/span>port<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\">\/\/ \u542f\u52a8\u670d\u52a1\u5668<\/span><br \/>\n    <span class=\"token keyword\">bool<\/span> <span class=\"token function\">Start<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> Handler<span class=\"token operator\">&amp;<\/span> handler<span class=\"token punctuation\">)<\/span><br \/>\n    <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/\/ 1. \u521b\u5efa\u76d1\u542cSocket<\/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><br \/>\n            AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n            SOCK_STREAM<span class=\"token punctuation\">,<\/span><br \/>\n            <span class=\"token number\">0<\/span><br \/>\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>listen_fd <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><br \/>\n            <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 boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ 2. \u8bbe\u7f6e\u5730\u5740\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><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">setsockopt<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                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>opt<span class=\"token punctuation\">,<\/span><br \/>\n                <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 operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><br \/>\n            <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 boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ 3. \u914d\u7f6e\u670d\u52a1\u5668IP\u4e0e\u7aef\u53e3<\/span><br \/>\n        sockaddr_in addr<span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        addr<span class=\"token punctuation\">.<\/span>sin_family <span class=\"token operator\">&#061;<\/span> AF_INET<span class=\"token punctuation\">;<\/span><\/p>\n<p>        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>port_<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><br \/>\n                AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n                ip_<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><br \/>\n                <span class=\"token operator\">&amp;<\/span>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><br \/>\n        <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">fprintf<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                <span class=\"token constant\">stderr<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                <span class=\"token string\">&#034;invalid IP: %s\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                ip_<span class=\"token punctuation\">.<\/span><span class=\"token function\">c_str<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><br \/>\n            <span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <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 boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ 4. \u7ed1\u5b9a<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">bind<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                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 operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><br \/>\n            <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 boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ 5. \u76d1\u542c<\/span><br \/>\n        <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> <span class=\"token number\">16<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><br \/>\n            <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 boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ 6. \u521b\u5efaSelector<\/span><br \/>\n        Selector selector<span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ \u76d1\u542cSocket\u4e5f\u9700\u8981\u7531select\u76d1\u89c6<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>selector<span class=\"token punctuation\">.<\/span><span class=\"token function\">Add<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">fprintf<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                <span class=\"token constant\">stderr<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                <span class=\"token string\">&#034;listen fd exceeds FD_SETSIZE\\\\n&#034;<\/span><br \/>\n            <span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <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 boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><br \/>\n            <span class=\"token string\">&#034;listening on %s:%u\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n            ip_<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><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\">unsigned<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>port_<span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ 7. \u4e3b\u4e8b\u4ef6\u5faa\u73af<\/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><br \/>\n        <span class=\"token punctuation\">{<\/span><br \/>\n            std<span class=\"token double-colon punctuation\">::<\/span>vector<span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token operator\">&gt;<\/span> ready<span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">int<\/span> ret <span class=\"token operator\">&#061;<\/span> selector<span class=\"token punctuation\">.<\/span><span class=\"token function\">Wait<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>ready<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>ret <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><br \/>\n            <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><br \/>\n                <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 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\">\/\/ 8. \u904d\u5386\u6240\u6709\u8bfb\u5c31\u7eea\u7684\u63cf\u8ff0\u7b26<\/span><br \/>\n            <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd <span class=\"token operator\">:<\/span> ready<span class=\"token punctuation\">)<\/span><br \/>\n            <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token comment\">\/\/ \u76d1\u542cSocket\u5c31\u7eea&#xff1a;<\/span><br \/>\n                <span class=\"token comment\">\/\/ \u6709\u65b0\u7684\u5ba2\u6237\u7aef\u8fde\u63a5<\/span><br \/>\n                <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><br \/>\n                <span class=\"token punctuation\">{<\/span><br \/>\n                    <span class=\"token keyword\">int<\/span> client_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">accept<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                        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><br \/>\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>client_fd <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><br \/>\n                    <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">!&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span><br \/>\n                        <span class=\"token punctuation\">{<\/span><br \/>\n                            <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 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 comment\">\/\/ 9. \u65b0\u8fde\u63a5\u52a0\u5165select<\/span><br \/>\n                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>selector<span class=\"token punctuation\">.<\/span><span class=\"token function\">Add<\/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 function\">fprintf<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                            <span class=\"token constant\">stderr<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                            <span class=\"token string\">&#034;fd&#061;%d exceeds select limit\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                            client_fd<br \/>\n                        <span class=\"token punctuation\">)<\/span><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                        <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\">\/\/ \u6bcf\u4e2a\u5ba2\u6237\u7aef\u4f7f\u7528\u72ec\u7acb\u8f93\u5165\u7f13\u51b2\u533a<\/span><br \/>\n                    inputs_<span class=\"token punctuation\">[<\/span>client_fd<span class=\"token punctuation\">]<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;&#034;<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                        <span class=\"token string\">&#034;client connected, fd&#061;%d\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                        client_fd<br \/>\n                    <span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><\/p>\n<p>                <span class=\"token comment\">\/\/ \u666e\u901a\u5ba2\u6237\u7aefSocket\u5c31\u7eea<\/span><br \/>\n                <span class=\"token keyword\">else<\/span><br \/>\n                <span class=\"token punctuation\">{<\/span><br \/>\n                    <span class=\"token function\">HandleClient<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                        fd<span class=\"token punctuation\">,<\/span><br \/>\n                        selector<span class=\"token punctuation\">,<\/span><br \/>\n                        handler<br \/>\n                    <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 comment\">\/\/ \u9519\u8bef\u9000\u51fa\u65f6\u5173\u95ed\u6240\u6709\u8fde\u63a5<\/span><br \/>\n        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">auto<\/span><span class=\"token operator\">&amp;<\/span> item <span class=\"token operator\">:<\/span> inputs_<span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>item<span class=\"token punctuation\">.<\/span>first<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        inputs_<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><\/p>\n<p>        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <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\">private<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token comment\">\/\/ \u53d1\u9001\u5168\u90e8\u54cd\u5e94<\/span><br \/>\n    <span class=\"token comment\">\/\/ \u672c\u6559\u5b66\u7248\u672c\u4f7f\u7528\u963b\u585e\u5f0f\u53d1\u9001<\/span><br \/>\n    <span class=\"token keyword\">bool<\/span> <span class=\"token function\">SendAll<\/span><span class=\"token punctuation\">(<\/span><br \/>\n        <span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token keyword\">const<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">&amp;<\/span> data<br \/>\n    <span class=\"token punctuation\">)<\/span><br \/>\n    <span class=\"token punctuation\">{<\/span><br \/>\n        size_t sent <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>sent <span class=\"token operator\">&lt;<\/span> data<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><br \/>\n        <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><br \/>\n                fd<span class=\"token punctuation\">,<\/span><br \/>\n                data<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<span class=\"token punctuation\">,<\/span><br \/>\n                data<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<span class=\"token punctuation\">,<\/span><br \/>\n                MSG_NOSIGNAL<br \/>\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>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><br \/>\n            <span class=\"token punctuation\">{<\/span><br \/>\n                sent <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>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 punctuation\">}<\/span><br \/>\n            <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span> <span class=\"token operator\">&amp;&amp;<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR<span class=\"token punctuation\">)<\/span><br \/>\n            <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            <span class=\"token keyword\">else<\/span><br \/>\n            <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 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 comment\">\/\/ \u79fb\u9664\u5e76\u5173\u95ed\u5ba2\u6237\u7aef<\/span><br \/>\n    <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> fd<span class=\"token punctuation\">,<\/span><br \/>\n        Selector<span class=\"token operator\">&amp;<\/span> selector<br \/>\n    <span class=\"token punctuation\">)<\/span><br \/>\n    <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u5148\u4eceselect\u4e2d\u79fb\u9664<\/span><br \/>\n        selector<span class=\"token punctuation\">.<\/span><span class=\"token function\">Del<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ \u5220\u9664\u8be5\u5ba2\u6237\u7aef\u7684\u8f93\u5165\u7f13\u51b2\u533a<\/span><br \/>\n        inputs_<span class=\"token punctuation\">.<\/span><span class=\"token function\">erase<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ \u6700\u540e\u5173\u95edSocket<\/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><\/p>\n<p>        <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><br \/>\n            <span class=\"token string\">&#034;client disconnected, fd&#061;%d\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n            fd<br \/>\n        <span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ \u5904\u7406\u5ba2\u6237\u7aef\u7684\u6570\u636e<\/span><br \/>\n    <span class=\"token keyword\">void<\/span> <span class=\"token function\">HandleClient<\/span><span class=\"token punctuation\">(<\/span><br \/>\n        <span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span><br \/>\n        Selector<span class=\"token operator\">&amp;<\/span> selector<span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token keyword\">const<\/span> Handler<span class=\"token operator\">&amp;<\/span> handler<br \/>\n    <span class=\"token punctuation\">)<\/span><br \/>\n    <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">char<\/span> buffer<span class=\"token punctuation\">[<\/span><span class=\"token number\">2048<\/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\">recv<\/span><span class=\"token punctuation\">(<\/span><br \/>\n            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><br \/>\n        <span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ \u5bf9\u7aef\u6b63\u5e38\u5173\u95ed<\/span><br \/>\n        <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><br \/>\n        <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">CloseClient<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> selector<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 comment\">\/\/ \u8bfb\u53d6\u51fa\u9519<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><br \/>\n                errno <span class=\"token operator\">&#061;&#061;<\/span> EINTR <span class=\"token operator\">||<\/span><br \/>\n                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<br \/>\n            <span class=\"token punctuation\">)<\/span><br \/>\n            <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 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><\/p>\n<p>            <span class=\"token function\">CloseClient<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> selector<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 comment\">\/\/ \u53d6\u5f97\u8be5\u5ba2\u6237\u7aef\u72ec\u7acb\u7684\u8f93\u5165\u7f13\u51b2\u533a<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">&amp;<\/span> pending <span class=\"token operator\">&#061;<\/span> inputs_<span class=\"token punctuation\">[<\/span>fd<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ TCP\u662f\u5b57\u8282\u6d41&#xff0c;\u9700\u8981\u7d2f\u79ef\u6570\u636e<\/span><br \/>\n        pending<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>size_t<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><br \/>\n        <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><br \/>\n        <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token comment\">\/\/ \u67e5\u627e\u4e00\u6761\u5b8c\u6574\u7684\u8bf7\u6c42<\/span><br \/>\n            size_t pos <span class=\"token operator\">&#061;<\/span> pending<span class=\"token punctuation\">.<\/span><span class=\"token function\">find<\/span><span class=\"token punctuation\">(<\/span><span class=\"token char\">&#039;\\\\n&#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>pos <span class=\"token operator\">&#061;&#061;<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token double-colon punctuation\">::<\/span>npos<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\">\/\/ \u63d0\u53d6\u4e00\u6761\u8bf7\u6c42<\/span><br \/>\n            std<span class=\"token double-colon punctuation\">::<\/span>string req <span class=\"token operator\">&#061;<\/span> pending<span class=\"token punctuation\">.<\/span><span class=\"token function\">substr<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">0<\/span><span class=\"token punctuation\">,<\/span> pos<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token comment\">\/\/ \u4ece\u7f13\u51b2\u533a\u5220\u9664\u5df2\u7ecf\u5904\u7406\u7684\u90e8\u5206<\/span><br \/>\n            pending<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> pos <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token comment\">\/\/ \u517c\u5bb9CRLF\u6362\u884c<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>req<span class=\"token punctuation\">.<\/span><span class=\"token function\">empty<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&amp;&amp;<\/span> req<span class=\"token punctuation\">.<\/span><span class=\"token function\">back<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token char\">&#039;\\\\r&#039;<\/span><span class=\"token punctuation\">)<\/span><br \/>\n            <span class=\"token punctuation\">{<\/span><br \/>\n                req<span class=\"token punctuation\">.<\/span><span class=\"token function\">pop_back<\/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 comment\">\/\/ \u9650\u5236\u5355\u6761\u8bf7\u6c42\u957f\u5ea6<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>req<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;<\/span> <span class=\"token number\">8192<\/span><span class=\"token punctuation\">)<\/span><br \/>\n            <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token function\">CloseClient<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> selector<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 comment\">\/\/ \u8c03\u7528\u4e1a\u52a1\u5904\u7406\u51fd\u6570<\/span><br \/>\n            std<span class=\"token double-colon punctuation\">::<\/span>string resp<span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token function\">handler<\/span><span class=\"token punctuation\">(<\/span>req<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>resp<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token comment\">\/\/ \u91c7\u7528\u6362\u884c\u7b26\u5206\u9694\u54cd\u5e94<\/span><br \/>\n            resp<span class=\"token punctuation\">.<\/span><span class=\"token function\">push_back<\/span><span class=\"token punctuation\">(<\/span><span class=\"token char\">&#039;\\\\n&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token comment\">\/\/ \u8fd4\u56de\u7ed3\u679c<\/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>fd<span class=\"token punctuation\">,<\/span> resp<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><br \/>\n            <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token function\">CloseClient<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> selector<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><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ \u9632\u6b62\u5ba2\u6237\u7aef\u4e00\u76f4\u53d1\u9001\u6ca1\u6709\u6362\u884c\u7684\u8d85\u957f\u8bf7\u6c42<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>pending<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;<\/span> <span class=\"token number\">8192<\/span><span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">fprintf<\/span><span class=\"token punctuation\">(<\/span><br \/>\n                <span class=\"token constant\">stderr<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                <span class=\"token string\">&#034;request line too long\\\\n&#034;<\/span><br \/>\n            <span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token function\">CloseClient<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> selector<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\">private<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token comment\">\/\/ \u670d\u52a1\u5668\u76d1\u542c\u5730\u5740<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string ip_<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ \u670d\u52a1\u5668\u76d1\u542c\u7aef\u53e3<\/span><br \/>\n    <span class=\"token keyword\">uint16_t<\/span> port_<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ \u6bcf\u4e2a\u5ba2\u6237\u7aef\u5bf9\u5e94\u4e00\u4e2a\u672a\u5b8c\u6210\u8bf7\u6c42\u7f13\u51b2\u533a<\/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> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">&gt;<\/span> inputs_<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<hr \/>\n<h2>\u4e8c\u5341\u4e8c\u3001\u9010\u6b65\u5206\u6790Selector\u7c7b<\/h2>\n<p>\u4e0a\u9762\u7684\u4ee3\u7801\u8f83\u957f&#xff0c;\u4f46select\u76f8\u5173\u903b\u8f91\u4e3b\u8981\u96c6\u4e2d\u5728&#xff1a;<\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Selector<\/span><\/p>\n<p>\u4e2d\u3002<\/p>\n<p>\u6211\u4eec\u5148\u628a\u5b83\u62c6\u5f00\u7406\u89e3\u3002<\/p>\n<h3>22.1 \u6784\u9020\u51fd\u6570<\/h3>\n<p><span class=\"token function\">Selector<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">:<\/span> <span class=\"token function\">max_fd_<\/span><span class=\"token punctuation\">(<\/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><br \/>\n    <span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>master_<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u4e3a\u4ec0\u4e48\u9700\u8981\u521d\u59cb\u5316&#xff1a;<\/p>\n<p><span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>master_<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u56e0\u4e3a&#xff1a;<\/p>\n<p>fd_set<\/p>\n<p>\u4e0d\u80fd\u5047\u5b9a\u521d\u59cb\u5185\u5bb9\u90fd\u662f0\u3002<\/p>\n<p>\u5982\u679c\u6ca1\u6709\u521d\u59cb\u5316&#xff0c;\u4f4d\u56fe\u53ef\u80fd\u5305\u542b\u4e0d\u7b26\u5408\u9884\u671f\u7684\u6570\u636e\u3002<\/p>\n<p>\u56e0\u6b64\u5fc5\u987b\u6e05\u7a7a\u96c6\u5408\u3002<\/p>\n<p>\u4e3a\u4ec0\u4e48&#xff1a;<\/p>\n<p>max_fd_ <span class=\"token operator\">&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u56e0\u4e3a&#xff1a;<\/p>\n<p>\u5f53\u524d\u8fd8\u6ca1\u6709\u9700\u8981\u76d1\u89c6\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26<\/p>\n<p>\u6240\u4ee5\u6682\u65f6\u6ca1\u6709\u6709\u6548\u6700\u5927fd\u3002<\/p>\n<h3>22.2 Add\u51fd\u6570<\/h3>\n<p><span class=\"token keyword\">bool<\/span> <span class=\"token function\">Add<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>fd <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span> <span class=\"token operator\">||<\/span> fd <span class=\"token operator\">&gt;&#061;<\/span> FD_SETSIZE<span class=\"token punctuation\">)<\/span><br \/>\n    <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\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>master_<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>fd <span class=\"token operator\">&gt;<\/span> max_fd_<span class=\"token punctuation\">)<\/span><br \/>\n    <span class=\"token punctuation\">{<\/span><br \/>\n        max_fd_ <span class=\"token operator\">&#061;<\/span> fd<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>\u4f8b\u5982&#xff1a;<\/p>\n<p>selector<span class=\"token punctuation\">.<\/span><span class=\"token function\">Add<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">3<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>\u5c06fd3\u52a0\u5165select\u8bfb\u96c6\u5408<\/p>\n<p>\u5982\u679c\u7ee7\u7eed&#xff1a;<\/p>\n<p>selector<span class=\"token punctuation\">.<\/span><span class=\"token function\">Add<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u90a3\u4e48&#xff1a;<\/p>\n<p>max_fd_ &#061; 5<\/p>\n<p>\u8fd9\u91cc\u9700\u8981\u68c0\u67e5&#xff1a;<\/p>\n<p>fd <span class=\"token operator\">&gt;&#061;<\/span> FD_SETSIZE<\/p>\n<p>\u9632\u6b62\u4f7f\u7528\u8d85\u51fa\u96c6\u5408\u8303\u56f4\u7684\u63cf\u8ff0\u7b26\u7f16\u53f7\u3002<\/p>\n<h3>22.3 Del\u51fd\u6570<\/h3>\n<p><span class=\"token function\">FD_CLR<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>master_<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8d1f\u8d23\u4ece\u96c6\u5408\u5220\u9664\u63cf\u8ff0\u7b26\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>\u539f\u6765&#xff1a;<\/p>\n<p>fd3\u3001fd4\u3001fd5<\/p>\n<p>\u5220\u9664&#xff1a;<\/p>\n<p>fd5<\/p>\n<p>\u4ee5\u540e&#xff1a;<\/p>\n<p>\u5269\u4f59&#xff1a;<\/p>\n<p>fd3\u3001fd4<\/p>\n<p>\u6700\u5927fd\u9700\u8981\u4ece&#xff1a;<\/p>\n<p>5<\/p>\n<p>\u53d8\u6210&#xff1a;<\/p>\n<p>4<\/p>\n<p>\u56e0\u6b64\u9700\u8981\u91cd\u65b0\u8ba1\u7b97\u3002<\/p>\n<h3>22.4 Wait\u51fd\u6570<\/h3>\n<p>\u6838\u5fc3\u4ee3\u7801&#xff1a;<\/p>\n<p>fd_set temp <span class=\"token operator\">&#061;<\/span> master_<span class=\"token punctuation\">;<\/span><\/p>\n<p>\u4e3a\u4ec0\u4e48\u590d\u5236&#xff1f;<\/p>\n<p>\u56e0\u4e3a&#xff1a;<\/p>\n<p>select\u4f1a\u4fee\u6539\u4f20\u5165\u7684\u96c6\u5408\u3002<\/p>\n<p>\u7136\u540e&#xff1a;<\/p>\n<p><span class=\"token keyword\">int<\/span> ret <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><br \/>\n    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>temp<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><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u7b49\u5f85\u4efb\u610f\u4e00\u4e2a\u88ab\u76d1\u89c6\u63cf\u8ff0\u7b26\u6ee1\u8db3\u8bfb\u5c31\u7eea\u6761\u4ef6\u3002<\/p>\n<p>\u8fd4\u56de\u4ee5\u540e&#xff1a;<\/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\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> fd <span class=\"token operator\">&lt;&#061;<\/span> max_fd_<span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>fd<span class=\"token punctuation\">)<\/span><br \/>\n<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>temp<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><br \/>\n    <span class=\"token punctuation\">{<\/span><br \/>\n        ready<span class=\"token operator\">-&gt;<\/span><span class=\"token function\">push_back<\/span><span class=\"token punctuation\">(<\/span>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>\u627e\u51fa&#xff1a;<\/p>\n<p>\u5df2\u7ecf\u8bfb\u5c31\u7eea\u7684\u63cf\u8ff0\u7b26<\/p>\n<p>\u6700\u7ec8\u901a\u8fc7&#xff1a;<\/p>\n<p>std<span class=\"token double-colon punctuation\">::<\/span>vector<span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">int<\/span><span class=\"token operator\">&gt;<\/span><\/p>\n<p>\u8fd4\u56de\u7ed9\u670d\u52a1\u5668\u3002<\/p>\n<p>\u8fd9\u91cc\u6700\u5173\u952e\u7684\u8bbe\u8ba1\u662f&#xff1a;<\/p>\n<p>master_\u4fdd\u5b58\u957f\u671f\u76d1\u89c6\u96c6\u5408<\/p>\n<p>temp\u4fdd\u5b58\u672c\u6b21select\u7684\u7ed3\u679c<\/p>\n<h3>22.5 \u4e3a\u4ec0\u4e48\u4e0d\u76f4\u63a5\u628a\u6574\u4e2aTcpSocket\u5bf9\u8c61\u590d\u5236\u5230\u96c6\u5408\u4e2d&#xff1f;<\/h3>\n<p>\u5bf9\u4e8e\u81ea\u5b9a\u4e49Socket\u5c01\u88c5\u7c7b&#xff0c;\u9700\u8981\u5148\u660e\u786e&#xff1a;<\/p>\n<p>\u8c01\u62e5\u6709\u6587\u4ef6\u63cf\u8ff0\u7b26&#xff1f;<\/p>\n<p>\u8c01\u8d1f\u8d23close&#xff1f;<\/p>\n<p>\u5bf9\u8c61\u590d\u5236\u662f\u5426\u590d\u5236\u6240\u6709\u6743&#xff1f;<\/p>\n<p>\u5982\u679c\u591a\u4e2aTcpSocket\u5bf9\u8c61\u7b80\u5355\u590d\u5236\u540c\u4e00\u4e2afd&#xff0c;\u5e76\u4e14\u5404\u81ea\u90fd\u5728\u6790\u6784\u65f6\u6267\u884cclose&#xff0c;\u53ef\u80fd\u9020\u6210\u91cd\u590d\u5173\u95ed\u3002<\/p>\n<p>\u5f53\u524d\u7248\u672c\u8ba9Selector\u53ea\u4fdd\u5b58&#xff1a;<\/p>\n<p><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">;<\/span><\/p>\n<p>\u4e0d\u8d1f\u8d23\u5173\u95edSocket\u3002<\/p>\n<p>Socket\u5173\u95ed\u64cd\u4f5c\u7531&#xff1a;<\/p>\n<p>TcpSelectServer<\/p>\n<p>\u96c6\u4e2d\u7ba1\u7406\u3002<\/p>\n<p>\u8fd9\u6837\u66f4\u5bb9\u6613\u7406\u89e3\u6587\u4ef6\u63cf\u8ff0\u7b26\u7684\u751f\u547d\u5468\u671f\u3002<\/p>\n<hr \/>\n<h2>\u4e8c\u5341\u4e09\u3001\u9010\u6b65\u5206\u6790TcpSelectServer<\/h2>\n<p>\u73b0\u5728\u7ee7\u7eed\u5206\u6790\u670d\u52a1\u5668\u7c7b\u3002<\/p>\n<h3>23.1 \u521b\u5efa\u76d1\u542cSocket<\/h3>\n<p><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><br \/>\n    AF_INET<span class=\"token punctuation\">,<\/span><br \/>\n    SOCK_STREAM<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token number\">0<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8fd9\u91cc&#xff1a;<\/p>\n<p>AF_INET<\/p>\n<p>\u8868\u793aIPv4\u3002<\/p>\n<p>SOCK_STREAM<\/p>\n<p>\u8868\u793a\u5b57\u8282\u6d41Socket\u3002<\/p>\n<p>\u5bf9\u4e8eTCP\u7f51\u7edc\u670d\u52a1&#xff0c;\u901a\u5e38\u4f7f\u7528&#xff1a;<\/p>\n<p>AF_INET &#043; SOCK_STREAM<\/p>\n<p>\u7ec4\u5408\u3002<\/p>\n<h3>23.2 \u7ed1\u5b9a\u7aef\u53e3<\/h3>\n<p><span class=\"token function\">bind<\/span><span class=\"token punctuation\">(<\/span>listen_fd<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>\u7528\u4e8e\u7ed1\u5b9a\u670d\u52a1\u5668\u7684&#xff1a;<\/p>\n<p>IP\u5730\u5740<\/p>\n<p>\u7aef\u53e3\u53f7<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>127.0.0.1:9090<\/p>\n<h3>23.3 \u5f00\u59cb\u76d1\u542c<\/h3>\n<p><span class=\"token function\">listen<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span> <span class=\"token number\">16<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u4f7fSocket\u8fdb\u5165\u76d1\u542c\u72b6\u6001\u3002<\/p>\n<h3>23.4 \u4e3a\u4ec0\u4e48\u76d1\u542cSocket\u4e5f\u8981\u52a0\u5165select&#xff1f;<\/h3>\n<p>\u56e0\u4e3a\u6211\u4eec\u4e0d\u4ec5\u9700\u8981\u76d1\u89c6&#xff1a;<\/p>\n<p>\u5ba2\u6237\u7aef\u6709\u6ca1\u6709\u53d1\u9001\u6570\u636e<\/p>\n<p>\u8fd8\u9700\u8981\u76d1\u89c6&#xff1a;<\/p>\n<p>\u6709\u6ca1\u6709\u65b0\u7684\u5ba2\u6237\u7aef\u8fde\u63a5<\/p>\n<p>\u56e0\u6b64&#xff1a;<\/p>\n<p>selector<span class=\"token punctuation\">.<\/span><span class=\"token function\">Add<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u975e\u5e38\u91cd\u8981\u3002<\/p>\n<p>\u5982\u679c\u6ca1\u6709\u52a0\u5165\u76d1\u542c\u63cf\u8ff0\u7b26&#xff1a;<\/p>\n<p>select\u4e0d\u4f1a\u66ff\u6211\u4eec\u62a5\u544a\u76d1\u542cSocket\u7684\u8bfb\u5c31\u7eea\u72b6\u6001<\/p>\n<h3>23.5 \u4e3a\u4ec0\u4e48\u65b0\u5ba2\u6237\u7aef\u4e5f\u8981\u52a0\u5165select&#xff1f;<\/h3>\n<p>\u5f53&#xff1a;<\/p>\n<p><span class=\"token function\">accept<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u6210\u529f\u65f6&#xff0c;\u4f1a\u8fd4\u56de\u65b0\u7684&#xff1a;<\/p>\n<p>client_fd<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>client_fd &#061; 4<\/p>\n<p>\u6b64\u65f6\u5fc5\u987b\u8c03\u7528&#xff1a;<\/p>\n<p>selector<span class=\"token punctuation\">.<\/span><span class=\"token function\">Add<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u56e0\u4e3a&#xff1a;<\/p>\n<p>\u76d1\u542cSocket\u8d1f\u8d23\u63a5\u6536\u65b0\u8fde\u63a5<\/p>\n<p>\u800c&#xff1a;<\/p>\n<p>client_fd\u8d1f\u8d23\u63a5\u6536\u8fd9\u4e2a\u5ba2\u6237\u7aef\u7684\u4e1a\u52a1\u6570\u636e<\/p>\n<p>\u8fd9\u4e24\u4e2aSocket\u7684\u7528\u9014\u4e0d\u540c\u3002<\/p>\n<h3>23.6 \u5982\u679c\u5ba2\u6237\u7aef\u65ad\u5f00\u600e\u4e48\u529e&#xff1f;<\/h3>\n<p>\u5728\u9002\u5f53\u7684TCP\u5173\u95ed\u573a\u666f\u4e0b&#xff1a;<\/p>\n<p><span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u8fd4\u56de&#xff1a;<\/p>\n<p>0<\/p>\n<p>\u8bf4\u660e\u63a5\u6536\u5230\u4e86EOF\u3002<\/p>\n<p>\u8fd9\u65f6\u9700\u8981&#xff1a;<\/p>\n<p>selector<span class=\"token punctuation\">.<\/span><span class=\"token function\">Del<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u7136\u540e&#xff1a;<\/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><\/p>\n<p>\u4e3a\u4ec0\u4e48\u8981\u5148\u4eceselect\u5220\u9664&#xff1f;<\/p>\n<p>\u56e0\u4e3a&#xff1a;<\/p>\n<p>\u8fd9\u4e2a\u63cf\u8ff0\u7b26\u5df2\u7ecf\u4e0d\u5e94\u8be5\u7ee7\u7eed\u88ab\u76d1\u89c6<\/p>\n<p>\u5982\u679c\u5173\u95ed\u4ee5\u540e\u6ca1\u6709\u4ece\u76d1\u89c6\u96c6\u5408\u5220\u9664&#xff0c;\u4e0b\u4e00\u8f6eselect\u53ef\u80fd\u9047\u5230\u65e0\u6548\u63cf\u8ff0\u7b26\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>EBADF<\/p>\n<p>\u53e6\u5916&#xff0c;\u6587\u4ef6\u63cf\u8ff0\u7b26\u7f16\u53f7\u53ef\u80fd\u88ab\u540e\u7eed\u65b0\u8fde\u63a5\u590d\u7528\u3002<\/p>\n<p>\u56e0\u6b64\u5e94\u8be5\u660e\u786e\u7ba1\u7406&#xff1a;<\/p>\n<p>\u63cf\u8ff0\u7b26\u52a0\u5165<\/p>\n<p>\u63cf\u8ff0\u7b26\u79fb\u9664<\/p>\n<p>\u63cf\u8ff0\u7b26\u5173\u95ed<\/p>\n<p>\u7684\u8fc7\u7a0b\u3002<\/p>\n<hr \/>\n<h2>\u4e8c\u5341\u56db\u3001\u5b8c\u6574\u5b9e\u73b0dict_server.cpp<\/h2>\n<p>\u73b0\u5728\u7f16\u5199\u5b57\u5178\u670d\u52a1\u5668\u7684\u4e1a\u52a1\u5165\u53e3\u3002<\/p>\n<p>\u6587\u4ef6&#xff1a;<\/p>\n<p>dict_server.cpp<\/p>\n<p>\u5b8c\u6574\u4ee3\u7801&#xff1a;<\/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\">&#034;select_server.hpp&#034;<\/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;unordered_map&gt;<\/span><\/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><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token comment\">\/\/ 1. \u5b9a\u4e49\u5b57\u5178<\/span><br \/>\n    <span class=\"token keyword\">const<\/span> std<span class=\"token double-colon punctuation\">::<\/span>unordered_map<span class=\"token operator\">&lt;<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token punctuation\">,<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span>string<br \/>\n    <span class=\"token operator\">&gt;<\/span> dict <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><span class=\"token string\">&#034;hello&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;\u4f60\u597d&#034;<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><span class=\"token string\">&#034;world&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;\u4e16\u754c&#034;<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><span class=\"token string\">&#034;apple&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;\u82f9\u679c&#034;<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><span class=\"token string\">&#034;linux&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;Linux\u64cd\u4f5c\u7cfb\u7edf&#034;<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><span class=\"token string\">&#034;select&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;I\/O\u591a\u8def\u8f6c\u63a5&#034;<\/span><span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ 2. \u5b9a\u4e49\u4e1a\u52a1\u5904\u7406\u51fd\u6570<\/span><br \/>\n    Handler handler <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">[<\/span><span class=\"token operator\">&amp;<\/span>dict<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">(<\/span><br \/>\n        <span class=\"token keyword\">const<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">&amp;<\/span> req<span class=\"token punctuation\">,<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">*<\/span> resp<br \/>\n    <span class=\"token punctuation\">)<\/span><br \/>\n    <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">auto<\/span> it <span class=\"token operator\">&#061;<\/span> dict<span class=\"token punctuation\">.<\/span><span class=\"token function\">find<\/span><span class=\"token punctuation\">(<\/span>req<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>it <span class=\"token operator\">!&#061;<\/span> dict<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><br \/>\n        <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token operator\">*<\/span>resp <span class=\"token operator\">&#061;<\/span> it<span class=\"token operator\">-&gt;<\/span>second<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token keyword\">else<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token operator\">*<\/span>resp <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;not found&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ 3. \u521b\u5efaselect\u670d\u52a1\u5668<\/span><br \/>\n    TcpSelectServer <span class=\"token function\">server<\/span><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 number\">9090<\/span><br \/>\n    <span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ 4. \u542f\u52a8\u670d\u52a1<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> server<span class=\"token punctuation\">.<\/span><span class=\"token function\">Start<\/span><span class=\"token punctuation\">(<\/span>handler<span class=\"token punctuation\">)<\/span> <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>24.1 \u4e3a\u4ec0\u4e48\u4f7f\u7528unordered_map&#xff1f;<\/h3>\n<p>\u56e0\u4e3a\u9700\u8981\u901a\u8fc7&#xff1a;<\/p>\n<p>\u82f1\u6587\u5355\u8bcd<\/p>\n<p>\u5feb\u901f\u67e5\u627e&#xff1a;<\/p>\n<p>\u5bf9\u5e94\u4e2d\u6587\u91ca\u4e49<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>dict<span class=\"token punctuation\">.<\/span><span class=\"token function\">find<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;hello&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5982\u679c\u627e\u5230&#xff1a;<\/p>\n<p>\u4f60\u597d<\/p>\n<p>\u5c31\u8fd4\u56de\u5bf9\u5e94\u7ed3\u679c\u3002<\/p>\n<h3>24.2 \u4e3a\u4ec0\u4e48\u4e1a\u52a1\u51fd\u6570\u4f7f\u7528Handler&#xff1f;<\/h3>\n<p>\u56e0\u4e3a\u6211\u4eec\u5e0c\u671b&#xff1a;<\/p>\n<p>TcpSelectServer\u53ea\u8d1f\u8d23\u7f51\u7edc\u901a\u4fe1<\/p>\n<p>\u800c&#xff1a;<\/p>\n<p>Handler\u8d1f\u8d23\u5177\u4f53\u4e1a\u52a1<\/p>\n<p>\u8fd9\u6837\u4ee5\u540e\u5982\u679c\u9700\u8981\u5c06\u5b57\u5178\u4e1a\u52a1\u6362\u6210\u5176\u4ed6\u4e1a\u52a1&#xff0c;\u4f8b\u5982&#xff1a;<\/p>\n<p>\u7b80\u5355\u8ba1\u7b97\u5668<\/p>\n<p>\u5b57\u7b26\u4e32\u5904\u7406<\/p>\n<p>\u5173\u952e\u5b57\u67e5\u8be2<\/p>\n<p>\u53ea\u9700\u8981\u66f4\u6362Handler\u3002<\/p>\n<p>\u4e0d\u5fc5\u91cd\u65b0\u4fee\u6539\u6574\u5957select\u4e8b\u4ef6\u5faa\u73af\u3002<\/p>\n<h3>24.3 \u4e3a\u4ec0\u4e48\u76d1\u542c127.0.0.1&#xff1f;<\/h3>\n<p>\u56e0\u4e3a&#xff1a;<\/p>\n<p>127.0.0.1<\/p>\n<p>\u662fIPv4\u73af\u56de\u5730\u5740\u3002<\/p>\n<p>\u8fd9\u91cc\u53ea\u9700\u8981\u5728\u672c\u673a\u6d4b\u8bd5\u3002<\/p>\n<p>\u5982\u679c\u8981\u5141\u8bb8\u5176\u4ed6\u8bbe\u5907\u901a\u8fc7\u76f8\u5e94\u7f51\u7edc\u63a5\u53e3\u8bbf\u95ee&#xff0c;\u9700\u8981\u6839\u636e\u5b9e\u9645\u73af\u5883\u4fee\u6539\u76d1\u542c\u5730\u5740\u5e76\u914d\u7f6e\u7f51\u7edc\u8bbf\u95ee\u89c4\u5219\u3002<\/p>\n<p>\u5bf9\u4e8e\u6559\u5b66\u5b9e\u9a8c&#xff0c;\u4f18\u5148\u9009\u62e9&#xff1a;<\/p>\n<p>127.0.0.1<\/p>\n<p>\u66f4\u5bb9\u6613\u63a7\u5236\u6d4b\u8bd5\u8303\u56f4\u3002<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/11\/20261106001822-6aed1cce9073a.png\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\" \/><\/p>\n<hr \/>\n<h2>\u4e8c\u5341\u4e94\u3001\u7f16\u8bd1\u8fd0\u884cTCP\u5b57\u5178\u670d\u52a1\u5668<\/h2>\n<p>\u6587\u4ef6\u7ed3\u6784&#xff1a;<\/p>\n<p>select-server\/<br \/>\n\u2502<br \/>\n\u251c\u2500\u2500 select_server.hpp<br \/>\n\u2502<br \/>\n\u2514\u2500\u2500 dict_server.cpp<\/p>\n<h3>25.1 \u7f16\u8bd1<\/h3>\n<p>\u5728Ubuntu\u7ec8\u7aef\u6267\u884c&#xff1a;<\/p>\n<p>g&#043;&#043; <span class=\"token parameter variable\">-std<\/span><span class=\"token operator\">&#061;<\/span>c&#043;&#043;11 <span class=\"token parameter variable\">-Wall<\/span> <span class=\"token parameter variable\">-Wextra<\/span> <span class=\"token punctuation\">\\\\<\/span><br \/>\n    dict_server.cpp <span class=\"token punctuation\">\\\\<\/span><br \/>\n    <span class=\"token parameter variable\">-o<\/span> dict_server<\/p>\n<h3>25.2 \u542f\u52a8<\/h3>\n<p>.\/dict_server<\/p>\n<p>\u9884\u671f\u8f93\u51fa&#xff1a;<\/p>\n<p>listening on 127.0.0.1:9090<\/p>\n<p>\u8868\u793a\u670d\u52a1\u5668\u5df2\u7ecf\u542f\u52a8\u3002<\/p>\n<h3>25.3 \u4f7f\u7528nc\u5ba2\u6237\u7aef\u6d4b\u8bd5<\/h3>\n<p>\u6253\u5f00\u7b2c\u4e8c\u4e2a\u7ec8\u7aef&#xff1a;<\/p>\n<p><span class=\"token function\">nc<\/span> <span class=\"token number\">127.0<\/span>.0.1 <span class=\"token number\">9090<\/span><\/p>\n<p>\u8f93\u5165&#xff1a;<\/p>\n<p>hello<\/p>\n<p>\u6309\u56de\u8f66\u3002<\/p>\n<p>\u670d\u52a1\u5668\u8fd4\u56de&#xff1a;<\/p>\n<p>\u4f60\u597d<\/p>\n<p>\u7ee7\u7eed\u8f93\u5165&#xff1a;<\/p>\n<p>apple<\/p>\n<p>\u8fd4\u56de&#xff1a;<\/p>\n<p>\u82f9\u679c<\/p>\n<p>\u8f93\u5165&#xff1a;<\/p>\n<p>unknown<\/p>\n<p>\u8fd4\u56de&#xff1a;<\/p>\n<p>not found<\/p>\n<h3>25.4 \u4e3a\u4ec0\u4e48\u5fc5\u987b\u6309\u56de\u8f66&#xff1f;<\/h3>\n<p>\u56e0\u4e3a\u6211\u4eec\u8bbe\u8ba1\u7684\u5e94\u7528\u534f\u8bae\u662f&#xff1a;<\/p>\n<p>\u6bcf\u6761\u8bf7\u6c42\u4ee5\\\\n\u7ed3\u675f<\/p>\n<p>\u670d\u52a1\u5668\u9700\u8981\u6536\u5230&#xff1a;<\/p>\n<p><span class=\"token char\">&#039;\\\\n&#039;<\/span><\/p>\n<p>\u624d\u8ba4\u4e3a\u4e00\u6761\u8bf7\u6c42\u5b8c\u6574\u3002<\/p>\n<p>\u56e0\u6b64\u76f4\u63a5\u8f93\u5165&#xff1a;<\/p>\n<p>hello<\/p>\n<p>\u4f46\u4e0d\u53d1\u9001\u6362\u884c\u65f6&#xff0c;\u670d\u52a1\u5668\u53ef\u80fd\u7ee7\u7eed\u7b49\u5f85\u5b8c\u6574\u8bf7\u6c42\u3002<\/p>\n<h3>25.5 \u540c\u65f6\u6253\u5f00\u591a\u4e2a\u5ba2\u6237\u7aef<\/h3>\n<p>\u73b0\u5728\u6253\u5f00\u4e09\u4e2a\u7ec8\u7aef\u3002<\/p>\n<p>\u5ba2\u6237\u7aefA&#xff1a;<\/p>\n<p><span class=\"token function\">nc<\/span> <span class=\"token number\">127.0<\/span>.0.1 <span class=\"token number\">9090<\/span><\/p>\n<p>\u5ba2\u6237\u7aefB&#xff1a;<\/p>\n<p><span class=\"token function\">nc<\/span> <span class=\"token number\">127.0<\/span>.0.1 <span class=\"token number\">9090<\/span><\/p>\n<p>\u5ba2\u6237\u7aefC&#xff1a;<\/p>\n<p><span class=\"token function\">nc<\/span> <span class=\"token number\">127.0<\/span>.0.1 <span class=\"token number\">9090<\/span><\/p>\n<p>\u5b83\u4eec\u90fd\u8fde\u63a5\u540c\u4e00\u4e2a\u670d\u52a1\u5668\u3002<\/p>\n<p>\u5047\u8bbe&#xff1a;<\/p>\n<p>\u5ba2\u6237\u7aefA\u8f93\u5165&#xff1a;<\/p>\n<p>hello<\/p>\n<p>\u6536\u5230&#xff1a;<\/p>\n<p>\u4f60\u597d<\/p>\n<p>\u5ba2\u6237\u7aefB\u8f93\u5165&#xff1a;<\/p>\n<p>world<\/p>\n<p>\u6536\u5230&#xff1a;<\/p>\n<p>\u4e16\u754c<\/p>\n<p>\u5ba2\u6237\u7aefC\u8f93\u5165&#xff1a;<\/p>\n<p>select<\/p>\n<p>\u6536\u5230&#xff1a;<\/p>\n<p>I\/O\u591a\u8def\u8f6c\u63a5<\/p>\n<p>\u8fd9\u5c31\u8bf4\u660e&#xff1a;<\/p>\n<p>\u4e00\u4e2aselect\u4e8b\u4ef6\u5faa\u73af\u53ef\u4ee5\u7ba1\u7406\u591a\u4e2a\u5ba2\u6237\u7aef\u8fde\u63a5\u3002<\/p>\n<h3>25.6 \u6d4b\u8bd5\u4e00\u6279\u8fde\u7eed\u8bf7\u6c42<\/h3>\n<p>\u4e5f\u53ef\u4ee5\u901a\u8fc7\u7ec8\u7aef\u547d\u4ee4\u4e00\u6b21\u53d1\u9001\u591a\u6761\u8bf7\u6c42\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p><span class=\"token builtin class-name\">printf<\/span> <span class=\"token string\">&#039;hello\\\\nworld\\\\napple\\\\n&#039;<\/span> <span class=\"token operator\">|<\/span> <span class=\"token function\">nc<\/span> <span class=\"token parameter variable\">-N<\/span> <span class=\"token number\">127.0<\/span>.0.1 <span class=\"token number\">9090<\/span><\/p>\n<p>\u5728\u652f\u6301 nc -N \u7684Ubuntu\u73af\u5883\u4e2d&#xff0c;\u53ef\u4ee5\u5f97\u5230&#xff1a;<\/p>\n<p>\u4f60\u597d<br \/>\n\u4e16\u754c<br \/>\n\u82f9\u679c<\/p>\n<p>\u8fd9\u4e2a\u6d4b\u8bd5\u8fd8\u80fd\u591f\u5e2e\u52a9\u9a8c\u8bc1&#xff1a;<\/p>\n<p>\u670d\u52a1\u5668\u662f\u5426\u6b63\u786e\u6309\u6362\u884c\u7b26\u5206\u5272\u591a\u6761TCP\u8bf7\u6c42\u3002<\/p>\n<p>\u5982\u679c\u7cfb\u7edf\u4e2d\u7684nc\u5b9e\u73b0\u4e0d\u652f\u6301 -N&#xff0c;\u53ef\u4ee5\u4f7f\u7528\u666e\u901a\u4ea4\u4e92\u5f0fnc\u6d4b\u8bd5\u3002<\/p>\n<hr \/>\n<h2>\u4e8c\u5341\u516d\u3001\u6574\u4e2aselect\u4e8b\u4ef6\u5faa\u73af\u7a76\u7adf\u53d1\u751f\u4e86\u4ec0\u4e48&#xff1f;<\/h2>\n<p>\u73b0\u5728\u6211\u4eec\u7ed3\u5408\u4e09\u4e2a\u5ba2\u6237\u7aef&#xff0c;\u91cd\u65b0\u68b3\u7406\u670d\u52a1\u5668\u7684\u5b8c\u6574\u6d41\u7a0b\u3002<\/p>\n<p>\u5047\u8bbe&#xff1a;<\/p>\n<p>\u76d1\u542cSocket&#xff1a;<\/p>\n<p>fd3<\/p>\n<p>\u5ba2\u6237\u7aefA\u8fde\u63a5\u4ee5\u540e&#xff1a;<\/p>\n<p>fd4<\/p>\n<p>\u5ba2\u6237\u7aefB\u8fde\u63a5\u4ee5\u540e&#xff1a;<\/p>\n<p>fd5<\/p>\n<p>\u5ba2\u6237\u7aefC\u8fde\u63a5\u4ee5\u540e&#xff1a;<\/p>\n<p>fd6<\/p>\n<p>\u90a3\u4e48&#xff1a;<\/p>\n<p>master\u96c6\u5408&#xff1a;<\/p>\n<p>fd3\u3001fd4\u3001fd5\u3001fd6<\/p>\n<h3>26.1 \u7b2c\u4e00\u8f6e&#xff1a;\u6ca1\u6709\u5ba2\u6237\u7aef\u6570\u636e<\/h3>\n<p>\u670d\u52a1\u5668\u6267\u884c&#xff1a;<\/p>\n<p>selector<span class=\"token punctuation\">.<\/span><span class=\"token function\">Wait<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>ready<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5185\u90e8\u8c03\u7528&#xff1a;<\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span>maxfd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/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>\u5373&#xff1a;<\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">7<\/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>\u5047\u8bbe&#xff1a;<\/p>\n<p>\u6240\u6709\u5ba2\u6237\u7aef\u6682\u65f6\u6ca1\u6709\u6570\u636e<\/p>\n<p>\u90a3\u4e48\u7ebf\u7a0b\u53ef\u4ee5\u5728select\u4e2d\u7b49\u5f85\u3002<\/p>\n<h3>26.2 \u7b2c\u4e8c\u8f6e&#xff1a;\u5ba2\u6237\u7aefB\u53d1\u9001\u6570\u636e<\/h3>\n<p>\u5ba2\u6237\u7aefB&#xff1a;<\/p>\n<p>fd5<\/p>\n<p>\u6536\u5230&#xff1a;<\/p>\n<p>hello\\\\n<\/p>\n<p>\u6b64\u65f6&#xff1a;<\/p>\n<p>fd5\u6ee1\u8db3\u8bfb\u5c31\u7eea\u6761\u4ef6<\/p>\n<p>select\u8fd4\u56de\u3002<\/p>\n<p>\u4e34\u65f6\u96c6\u5408\u4e2d&#xff1a;<\/p>\n<p>fd5\u5bf9\u5e94\u4f4d\u7f6e\u88ab\u8bbe\u7f6e<\/p>\n<p>\u670d\u52a1\u5668\u901a\u8fc7&#xff1a;<\/p>\n<p><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>temp<span class=\"token punctuation\">)<\/span><\/p>\n<p>\u8bc6\u522b\u5c31\u7eea\u63cf\u8ff0\u7b26\u3002<\/p>\n<p>\u968f\u540e&#xff1a;<\/p>\n<p><span class=\"token function\">HandleClient<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">5<\/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>\u8c03\u7528&#xff1a;<\/p>\n<p><span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">5<\/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>\u53d6\u5f97\u5ba2\u6237\u7aefB\u7684\u6570\u636e\u3002<\/p>\n<h3>26.3 \u7b2c\u4e09\u8f6e&#xff1a;\u5ba2\u6237\u7aefA\u548cC\u540c\u65f6\u53d1\u9001<\/h3>\n<p>\u5047\u8bbe&#xff1a;<\/p>\n<p>fd4\u53ef\u8bfb<\/p>\n<p>fd6\u53ef\u8bfb<\/p>\n<p>select\u8fd4\u56de\u4ee5\u540e&#xff1a;<\/p>\n<p>ready &#061; {4, 6}<\/p>\n<p>\u670d\u52a1\u5668\u4f9d\u6b21\u5904\u7406&#xff1a;<\/p>\n<p>\u5ba2\u6237\u7aefA<\/p>\n<p>\u5ba2\u6237\u7aefC<\/p>\n<h3>26.4 \u7b2c\u56db\u8f6e&#xff1a;\u5ba2\u6237\u7aefC\u65ad\u5f00\u8fde\u63a5<\/h3>\n<p>\u5047\u8bbe&#xff1a;<\/p>\n<p><span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">6<\/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>\u8fd4\u56de&#xff1a;<\/p>\n<p>0<\/p>\n<p>\u90a3\u4e48\u670d\u52a1\u5668\u6267\u884c&#xff1a;<\/p>\n<p>selector<span class=\"token punctuation\">.<\/span><span class=\"token function\">Del<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">6<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u518d\u5173\u95ed&#xff1a;<\/p>\n<p><span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">6<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u6b64\u65f6\u4e3b\u96c6\u5408\u53d8\u4e3a&#xff1a;<\/p>\n<p>fd3\u3001fd4\u3001fd5<\/p>\n<p>\u5982\u679c\u539f\u6765\u7684\u6700\u5927fd\u662f&#xff1a;<\/p>\n<p>6<\/p>\n<p>\u5219\u9700\u8981\u91cd\u65b0\u8ba1\u7b97&#xff1a;<\/p>\n<p>maxfd &#061; 5<\/p>\n<p>\u4e0b\u4e00\u6b21\u8c03\u7528&#xff1a;<\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">6<\/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>\u8fd9\u6837\u5c31\u5b8c\u6210\u4e86\u4e00\u4e2a\u7b80\u5355\u7684\u591a\u5ba2\u6237\u7aef\u4e8b\u4ef6\u5faa\u73af\u3002<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/11\/20261106001824-6aed1cd004139.png\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\" \/><\/p>\n<hr \/>\n<h2>\u4e8c\u5341\u4e03\u3001\u8fd9\u4e2a\u670d\u52a1\u5668\u8fd8\u6709\u54ea\u4e9b\u9700\u8981\u6ce8\u610f\u7684\u5730\u65b9&#xff1f;<\/h2>\n<p>\u524d\u9762\u7684\u7a0b\u5e8f\u80fd\u591f\u4f5c\u4e3aselect\u7684\u5165\u95e8\u5b9e\u9a8c&#xff0c;\u4f46\u6211\u4eec\u8fd8\u9700\u8981\u6e05\u695a\u5b83\u7684\u9002\u7528\u8303\u56f4\u3002<\/p>\n<h3>27.1 select\u53ea\u8d1f\u8d23\u62a5\u544a\u5c31\u7eea<\/h3>\n<p>\u6211\u4eec\u4f7f\u7528&#xff1a;<\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u68c0\u6d4b\u8bfb\u5c31\u7eea\u3002<\/p>\n<p>\u5b83\u4e0d\u4f1a\u81ea\u52a8\u5e2e\u6211\u4eec\u8c03\u7528&#xff1a;<\/p>\n<p><span class=\"token function\">accept<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u6216\u8005&#xff1a;<\/p>\n<p><span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u8fd9\u4e9b\u64cd\u4f5c\u4ecd\u7136\u9700\u8981\u5e94\u7528\u7a0b\u5e8f\u5b8c\u6210\u3002<\/p>\n<h3>27.2 TCP\u4ecd\u7136\u662f\u5b57\u8282\u6d41<\/h3>\n<p>\u6240\u4ee5&#xff1a;<\/p>\n<p>\u4e00\u6b21recv<\/p>\n<p>\u4e0d\u4e00\u5b9a\u5bf9\u5e94&#xff1a;<\/p>\n<p>\u4e00\u6b21send<\/p>\n<p>\u672c\u4f8b\u901a\u8fc7&#xff1a;<\/p>\n<p>\\\\n<\/p>\n<p>\u5212\u5206\u5e94\u7528\u5c42\u8bf7\u6c42\u3002<\/p>\n<p>\u8fd9\u662f\u4e3a\u4e86\u907f\u514d\u9519\u8bef\u5730\u4f9d\u8d56TCP\u6d88\u606f\u8fb9\u754c\u3002<\/p>\n<h3>27.3 \u5f53\u524d\u670d\u52a1\u5668\u4f7f\u7528\u963b\u585e\u5f0f\u53d1\u9001<\/h3>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p><span class=\"token function\">SendAll<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> resp<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5185\u90e8\u4f1a\u5faa\u73af\u8c03\u7528&#xff1a;<\/p>\n<p><span class=\"token function\">send<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u76f4\u5230\u54cd\u5e94\u5168\u90e8\u53d1\u9001\u6216\u53d1\u751f\u9519\u8bef\u3002<\/p>\n<p>\u8fd9\u6837\u80fd\u591f\u5904\u7406\u90e8\u5206\u53d1\u9001\u7684\u95ee\u9898\u3002<\/p>\n<p>\u4f46\u662f&#xff0c;\u5982\u679c\u67d0\u4e2a\u5ba2\u6237\u7aef\u4e00\u76f4\u4e0d\u8bfb\u53d6\u6570\u636e&#xff0c;\u53d1\u9001\u7f13\u51b2\u533a\u8017\u5c3d\u65f6&#xff0c;\u5f53\u524d\u7ebf\u7a0b\u4ecd\u7136\u53ef\u80fd\u5728 send() \u4e2d\u7b49\u5f85\u3002<\/p>\n<p>\u8fd9\u4f1a\u5f71\u54cd\u5176\u4ed6\u5ba2\u6237\u7aef\u7684\u54cd\u5e94\u3002<\/p>\n<p>\u56e0\u6b64&#xff1a;<\/p>\n<p>\u4f7f\u7528select\u7ba1\u7406\u8bfb\u4e8b\u4ef6&#xff0c;\u5e76\u4e0d\u610f\u5473\u7740\u6574\u4e2a\u670d\u52a1\u5668\u5df2\u7ecf\u5b8c\u5168\u6ca1\u6709\u963b\u585e\u70b9\u3002<\/p>\n<p>\u5bf9\u4e8e\u66f4\u5b8c\u5584\u7684\u9ad8\u5e76\u53d1\u670d\u52a1\u5668&#xff0c;\u901a\u5e38\u8fd8\u9700\u8981&#xff1a;<\/p>\n<p>\u975e\u963b\u585eSocket<\/p>\n<p>\u5199\u5c31\u7eea\u4e8b\u4ef6<\/p>\n<p>\u6bcf\u5ba2\u6237\u7aef\u53d1\u9001\u7f13\u51b2\u533a<\/p>\n<p>\u90e8\u5206\u53d1\u9001\u5904\u7406<\/p>\n<p>\u7b49\u673a\u5236\u3002<\/p>\n<p>\u8fd9\u4e9b\u5185\u5bb9\u53ef\u4ee5\u5728\u540e\u7eed\u5b66\u4e60\u5b8c\u6574\u4e8b\u4ef6\u9a71\u52a8\u670d\u52a1\u5668\u65f6\u7ee7\u7eed\u5c55\u5f00\u3002<\/p>\n<h3>27.4 select\u8fd4\u56de\u540e&#xff0c;\u64cd\u4f5c\u5c31\u4e00\u5b9a\u6210\u529f\u5417&#xff1f;<\/h3>\n<p>\u4e0d\u4e00\u5b9a\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>select\u62a5\u544afd\u53ef\u8bfb<\/p>\n<p>\u968f\u540e&#xff1a;<\/p>\n<p><span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u4ecd\u7136\u5fc5\u987b\u68c0\u67e5\u8fd4\u56de\u503c\u3002<\/p>\n<p>\u56e0\u4e3a\u53ef\u80fd\u51fa\u73b0&#xff1a;<\/p>\n<p>\u6b63\u5e38\u8bfb\u53d6<\/p>\n<p>EOF<\/p>\n<p>\u9519\u8bef<\/p>\n<p>\u8fde\u63a5\u72b6\u6001\u53d8\u5316<\/p>\n<p>\u7b49\u60c5\u51b5\u3002<\/p>\n<h3>27.5 \u4e3a\u4ec0\u4e48\u4e0d\u80fd\u7b80\u5355\u590d\u5236Socket\u5bf9\u8c61&#xff1f;<\/h3>\n<p>\u5982\u679c\u81ea\u5b9a\u4e49TcpSocket\u7c7b\u7ba1\u7406\u6587\u4ef6\u63cf\u8ff0\u7b26\u7684\u5173\u95ed&#xff0c;\u800c\u591a\u4e2a\u5bf9\u8c61\u53c8\u5171\u4eab\u540c\u4e00\u4e2afd&#xff0c;\u5c31\u5fc5\u987b\u6b63\u786e\u5904\u7406\u5bf9\u8c61\u7684\u6240\u6709\u6743\u3002<\/p>\n<p>\u5426\u5219\u53ef\u80fd\u51fa\u73b0&#xff1a;<\/p>\n<p>\u91cd\u590dclose<\/p>\n<p>\u9519\u8bef\u5173\u95ed\u5176\u4ed6\u8fde\u63a5<\/p>\n<p>\u63cf\u8ff0\u7b26\u590d\u7528\u5bfc\u81f4\u7684\u95ee\u9898<\/p>\n<p>\u672c\u7bc7\u7684Selector\u53ea\u4fdd\u5b58\u63cf\u8ff0\u7b26\u7f16\u53f7&#xff0c;\u907f\u514d\u628aSocket\u5bf9\u8c61\u6240\u6709\u6743\u7ba1\u7406\u4e0eselect\u96c6\u5408\u7ba1\u7406\u6df7\u5728\u4e00\u8d77\u3002<\/p>\n<h3>27.6 \u5982\u679c\u5ba2\u6237\u7aef\u6570\u91cf\u5f88\u591a\u600e\u4e48\u529e&#xff1f;<\/h3>\n<p>select\u5b58\u5728&#xff1a;<\/p>\n<p>FD_SETSIZE\u9650\u5236<\/p>\n<p>\u6bcf\u6b21\u590d\u5236\u63cf\u8ff0\u7b26\u96c6\u5408<\/p>\n<p>\u5185\u6838\u68c0\u67e5\u63cf\u8ff0\u7b26\u96c6\u5408<\/p>\n<p>\u7528\u6237\u7a0b\u5e8f\u626b\u63cf\u5c31\u7eea\u4f4d\u56fe<\/p>\n<p>\u7b49\u95ee\u9898\u3002<\/p>\n<p>\u56e0\u6b64\u5b83\u9002\u5408\u5b66\u4e60I\/O\u591a\u8def\u8f6c\u63a5\u539f\u7406&#xff0c;\u4e5f\u9002\u5408\u67d0\u4e9b\u89c4\u6a21\u6709\u9650\u7684\u7f51\u7edc\u7a0b\u5e8f\u3002<\/p>\n<p>\u4f46\u5982\u679c\u76ee\u6807\u662f\u5927\u89c4\u6a21\u9ad8\u5e76\u53d1\u670d\u52a1\u5668&#xff0c;\u5c31\u9700\u8981\u7ee7\u7eed\u7814\u7a76\u5176\u4ed6\u4e8b\u4ef6\u901a\u77e5\u673a\u5236\u3002<\/p>\n<hr \/>\n<h2>\u4e8c\u5341\u516b\u3001select\u5e38\u89c1\u9762\u8bd5\u95ee\u9898<\/h2>\n<h3>28.1 select\u662f\u4ec0\u4e48&#xff1f;<\/h3>\n<p>select\u662f\u4e00\u79cdI\/O\u591a\u8def\u8f6c\u63a5\u63a5\u53e3\u3002<\/p>\n<p>\u5b83\u80fd\u591f\u540c\u65f6\u76d1\u89c6\u591a\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26\u7684\u53ef\u8bfb\u3001\u53ef\u5199\u53ca\u7279\u5b9a\u5f02\u5e38\u6761\u4ef6&#xff0c;\u5e76\u5728\u76f8\u5e94\u6761\u4ef6\u6ee1\u8db3\u6216\u8d85\u65f6\u7b49\u60c5\u51b5\u4e0b\u8fd4\u56de\u3002<\/p>\n<h3>28.2 select\u548c\u963b\u585erecv\u6709\u4ec0\u4e48\u533a\u522b&#xff1f;<\/h3>\n<p>\u963b\u585erecv\u4e3b\u8981\u9488\u5bf9\u4e00\u4e2a\u6307\u5b9aSocket\u6267\u884c\u8bfb\u53d6\u5e76\u7b49\u5f85\u7ed3\u679c\u3002<\/p>\n<p>select\u53ef\u4ee5\u540c\u65f6\u7b49\u5f85\u591a\u4e2a\u63cf\u8ff0\u7b26\u7684\u5c31\u7eea\u6761\u4ef6\u3002<\/p>\n<h3>28.3 select\u662f\u5426\u5c5e\u4e8e\u5f02\u6b65I\/O&#xff1f;<\/h3>\n<p>\u5728\u7ecf\u5178\u4e94\u79cdI\/O\u6a21\u578b\u4e2d&#xff1a;<\/p>\n<p>\u4e0d\u662f\u3002<\/p>\n<p>select\u53ea\u8d1f\u8d23\u62a5\u544a\u5c31\u7eea&#xff0c;\u5e94\u7528\u7a0b\u5e8f\u4ecd\u7136\u9700\u8981\u8c03\u7528recv\u6267\u884c\u8bfb\u53d6\u3002<\/p>\n<h3>28.4 select\u7684\u7b2c\u4e00\u4e2a\u53c2\u6570\u662f\u4ec0\u4e48&#xff1f;<\/h3>\n<p>nfds<\/p>\n<p>\u8868\u793a&#xff1a;<\/p>\n<p>\u9700\u8981\u76d1\u89c6\u7684\u6700\u5927\u6587\u4ef6\u63cf\u8ff0\u7b26\u7f16\u53f7\u52a01\u3002<\/p>\n<h3>28.5 FD_ZERO\u662f\u4ec0\u4e48&#xff1f;<\/h3>\n<p>\u7528\u4e8e\u6e05\u7a7afd_set\u96c6\u5408\u3002<\/p>\n<h3>28.6 FD_SET\u662f\u4ec0\u4e48&#xff1f;<\/h3>\n<p>\u7528\u4e8e\u5c06\u6307\u5b9a\u6587\u4ef6\u63cf\u8ff0\u7b26\u52a0\u5165\u96c6\u5408\u3002<\/p>\n<h3>28.7 FD_ISSET\u662f\u4ec0\u4e48&#xff1f;<\/h3>\n<p>\u7528\u4e8e\u68c0\u67e5\u6307\u5b9a\u63cf\u8ff0\u7b26\u5728\u96c6\u5408\u4e2d\u5bf9\u5e94\u7684\u4f4d\u662f\u5426\u88ab\u8bbe\u7f6e\u3002<\/p>\n<h3>28.8 \u4e3a\u4ec0\u4e48\u6bcf\u6b21\u8c03\u7528select\u524d\u8981\u91cd\u5efafd_set&#xff1f;<\/h3>\n<p>\u56e0\u4e3aselect\u4f1a\u4fee\u6539\u4f20\u5165\u7684\u96c6\u5408&#xff0c;\u53ea\u4fdd\u7559\u76f8\u5e94\u5c31\u7eea\u7684\u63cf\u8ff0\u7b26\u4f4d\u3002<\/p>\n<h3>28.9 select\u8fd4\u56de0\u662f\u4ec0\u4e48\u610f\u601d&#xff1f;<\/h3>\n<p>\u5728\u8bbe\u7f6e\u4e86timeout\u7684\u60c5\u51b5\u4e0b&#xff1a;<\/p>\n<p>\u8868\u793a\u8d85\u65f6&#xff0c;\u672a\u68c0\u6d4b\u5230\u5bf9\u5e94\u5c31\u7eea\u4e8b\u4ef6\u3002<\/p>\n<h3>28.10 \u4e3a\u4ec0\u4e48\u76d1\u542cSocket\u8bfb\u5c31\u7eea\u8981\u8c03\u7528accept&#xff1f;<\/h3>\n<p>\u56e0\u4e3a\u76d1\u542cSocket\u8bfb\u5c31\u7eea\u901a\u5e38\u8868\u793a\u6709\u8fde\u63a5\u7b49\u5f85\u63a5\u53d7\u3002<\/p>\n<p>\u9700\u8981\u4f7f\u7528accept\u83b7\u53d6\u65b0\u7684\u5df2\u8fde\u63a5Socket\u3002<\/p>\n<h3>28.11 \u4e3a\u4ec0\u4e48\u5ba2\u6237\u7aefSocket\u8bfb\u5c31\u7eea\u540erecv\u53ef\u80fd\u8fd4\u56de0&#xff1f;<\/h3>\n<p>\u56e0\u4e3aTCP\u5bf9\u7aef\u6b63\u5e38\u7ed3\u675f\u53d1\u9001\u65f6&#xff0c;Socket\u53ef\u80fd\u62a5\u544a\u8bfb\u5c31\u7eea&#xff0c;\u800crecv\u8fd4\u56deEOF\u3002<\/p>\n<h3>28.12 \u4e3a\u4ec0\u4e48select\u8981\u7ef4\u62a4maxfd&#xff1f;<\/h3>\n<p>\u56e0\u4e3a&#xff1a;<\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span>maxfd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/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>\u9700\u8981\u6839\u636e\u6700\u5927\u63cf\u8ff0\u7b26\u786e\u5b9a\u68c0\u67e5\u8303\u56f4\u3002<\/p>\n<h3>28.13 select\u6700\u591a\u652f\u6301\u591a\u5c11\u4e2aSocket&#xff1f;<\/h3>\n<p>\u4e0d\u80fd\u7b80\u5355\u7ed9\u51fa\u4e00\u4e2a\u4e0e\u5e73\u53f0\u65e0\u5173\u7684\u56fa\u5b9a\u5ba2\u6237\u7aef\u6570\u91cf\u3002<\/p>\n<p>\u5e38\u89c1Linux\u7528\u6237\u6001\u63a5\u53e3\u4e2d&#xff1a;<\/p>\n<p>FD_SETSIZE <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1024<\/span><\/p>\n<p>\u9650\u5236fd_set\u80fd\u591f\u8868\u793a\u7684\u63cf\u8ff0\u7b26\u7f16\u53f7\u8303\u56f4\u3002<\/p>\n<p>\u7531\u4e8e\u8fd8\u5b58\u5728\u6807\u51c6\u6587\u4ef6\u63cf\u8ff0\u7b26\u3001\u76d1\u542cSocket\u53ca\u5176\u4ed6\u6587\u4ef6&#xff0c;\u80fd\u591f\u7ba1\u7406\u7684\u5ba2\u6237\u7aef\u6570\u91cf\u901a\u5e38\u5c11\u4e8e\u8fd9\u4e00\u6570\u5b57\u3002<\/p>\n<h3>28.14 select\u6700\u5927\u7684\u7f3a\u70b9\u662f\u4ec0\u4e48&#xff1f;<\/h3>\n<p>\u4e3b\u8981\u5305\u62ec&#xff1a;<\/p>\n<p>fd_set\u5bb9\u91cf\u9650\u5236<\/p>\n<p>\u6bcf\u6b21\u8c03\u7528\u9700\u8981\u91cd\u65b0\u51c6\u5907\u96c6\u5408<\/p>\n<p>\u7528\u6237\u6001\u4e0e\u5185\u6838\u6001\u4e4b\u95f4\u7684\u96c6\u5408\u4f20\u9012\u5f00\u9500<\/p>\n<p>\u5185\u6838\u68c0\u67e5\u63cf\u8ff0\u7b26\u7684\u6210\u672c<\/p>\n<p>\u5e94\u7528\u7a0b\u5e8f\u67e5\u627e\u5c31\u7eeafd\u7684\u6210\u672c<\/p>\n<p>\u56e0\u6b64\u5728\u5927\u89c4\u6a21\u8fde\u63a5\u573a\u666f\u4e2d\u5b58\u5728\u5c40\u9650\u6027\u3002<\/p>\n<hr \/>\n<hr \/>\n<h2>\u4e8c\u5341\u4e5d\u3001\u5168\u6587\u603b\u7ed3<\/h2>\n<p>\u672c\u6587\u7cfb\u7edf\u5b66\u4e60\u4e86Linux\u4e2d\u7684&#xff1a;<\/p>\n<p>select I\/O\u591a\u8def\u8f6c\u63a5\u673a\u5236\u3002<\/p>\n<p>\u9996\u5148\u4ece\u963b\u585erecv\u4e0e\u975e\u963b\u585e\u8f6e\u8be2\u7684\u95ee\u9898\u51fa\u53d1&#xff0c;\u8ba4\u8bc6\u4e86select\u7684\u6838\u5fc3\u4f5c\u7528&#xff1a;<\/p>\n<p>\u8ba9\u4e00\u4e2a\u6267\u884c\u6d41\u540c\u65f6\u7b49\u5f85\u591a\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26\u7684\u5c31\u7eea\u4e8b\u4ef6\u3002<\/p>\n<p>\u968f\u540e\u5b66\u4e60\u4e86\u51fd\u6570\u539f\u578b&#xff1a;<\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> nfds<span class=\"token punctuation\">,<\/span><br \/>\n    fd_set <span class=\"token operator\">*<\/span>readfds<span class=\"token punctuation\">,<\/span><br \/>\n    fd_set <span class=\"token operator\">*<\/span>writefds<span class=\"token punctuation\">,<\/span><br \/>\n    fd_set <span class=\"token operator\">*<\/span>exceptfds<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">timeval<\/span> <span class=\"token operator\">*<\/span>timeout<br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5176\u4e2d\u6700\u91cd\u8981\u7684\u51e0\u4e2a\u53c2\u6570\u662f&#xff1a;<\/p>\n<p>nfds&#xff1a;<\/p>\n<p>\u6700\u5927fd &#043; 1<\/p>\n<p>readfds&#xff1a;<\/p>\n<p>\u76d1\u89c6\u8bfb\u5c31\u7eea<\/p>\n<p>writefds&#xff1a;<\/p>\n<p>\u76d1\u89c6\u5199\u5c31\u7eea<\/p>\n<p>timeout&#xff1a;<\/p>\n<p>\u63a7\u5236\u7b49\u5f85\u65f6\u95f4<\/p>\n<p>\u63a5\u4e0b\u6765\u8be6\u7ec6\u5206\u6790\u4e86&#xff1a;<\/p>\n<p>fd_set<\/p>\n<p>\u7684\u4f4d\u56fe\u601d\u60f3\u3002<\/p>\n<p>\u4ee5\u53ca\u56db\u4e2a\u6838\u5fc3\u5b8f&#xff1a;<\/p>\n<p>FD_ZERO<br \/>\nFD_SET<br \/>\nFD_CLR<br \/>\nFD_ISSET<\/p>\n<p>\u5176\u4e2d\u5fc5\u987b\u8bb0\u4f4f&#xff1a;<\/p>\n<p>select\u4f1a\u4fee\u6539\u4f20\u5165\u7684fd_set&#xff0c;\u56e0\u6b64\u6bcf\u8f6e\u9700\u8981\u91cd\u65b0\u51c6\u5907\u63cf\u8ff0\u7b26\u96c6\u5408\u3002<\/p>\n<p>\u968f\u540e\u5206\u6790\u4e86Socket\u7684\u8bfb\u5199\u5c31\u7eea\u6761\u4ef6\u3002<\/p>\n<p>\u4f8b\u5982&#xff1a;<\/p>\n<p>\u63a5\u6536\u7f13\u51b2\u533a\u6709\u6570\u636e<\/p>\n<p>\u53ef\u80fd\u5bfc\u81f4\u8bfb\u5c31\u7eea\u3002<\/p>\n<p>\u5bf9\u7aef\u6b63\u5e38\u7ed3\u675f\u53d1\u9001<\/p>\n<p>\u4e5f\u53ef\u80fd\u5bfc\u81f4\u8bfb\u5c31\u7eea\u3002<\/p>\n<p>\u76d1\u542cSocket\u5b58\u5728\u5f85\u63a5\u53d7\u8fde\u63a5<\/p>\n<p>\u540c\u6837\u53ef\u80fd\u5bfc\u81f4\u8bfb\u5c31\u7eea\u3002<\/p>\n<p>\u56e0\u6b64&#xff1a;<\/p>\n<p>\u8bfb\u5c31\u7eea\u4e0d\u7b49\u4e8erecv\u4e00\u5b9a\u8fd4\u56de\u6b63\u6570\u3002<\/p>\n<p>\u4e4b\u540e\u5206\u6790\u4e86select\u7684\u4e3b\u8981\u5c40\u9650&#xff1a;<\/p>\n<p>fd_set\u5bb9\u91cf\u9650\u5236<\/p>\n<p>\u96c6\u5408\u53cd\u590d\u590d\u5236<\/p>\n<p>\u63cf\u8ff0\u7b26\u68c0\u67e5\u6210\u672c<\/p>\n<p>\u5e94\u7528\u7a0b\u5e8f\u626b\u63cf\u5c31\u7eea\u4f4d\u56fe<\/p>\n<p>\u6700\u540e\u5b8c\u6210\u4e86\u4e24\u4e2a\u5b9e\u9a8c\u3002<\/p>\n<p>\u7b2c\u4e00\u4e2a\u5b9e\u9a8c&#xff1a;<\/p>\n<p>\u4f7f\u7528select\u76d1\u542c\u6807\u51c6\u8f93\u5165\u3002<\/p>\n<p>\u7b2c\u4e8c\u4e2a\u5b9e\u9a8c&#xff1a;<\/p>\n<p>\u4f7f\u7528select\u540c\u65f6\u7ba1\u7406\u591a\u4e2aTCP\u5ba2\u6237\u7aef&#xff0c;\u5b9e\u73b0\u5b57\u5178\u670d\u52a1\u5668\u3002<\/p>\n<p>\u5728\u670d\u52a1\u5668\u4e2d&#xff0c;\u6211\u4eec\u8bbe\u8ba1&#xff1a;<\/p>\n<p>Selector<\/p>\n<p>\u8d1f\u8d23&#xff1a;<\/p>\n<p>Add<\/p>\n<p>Del<\/p>\n<p>Wait<\/p>\n<p>\u5e76\u8bbe\u8ba1&#xff1a;<\/p>\n<p>TcpSelectServer<\/p>\n<p>\u8d1f\u8d23&#xff1a;<\/p>\n<p>\u521b\u5efa\u76d1\u542cSocket<\/p>\n<p>\u63a5\u53d7\u5ba2\u6237\u7aef\u8fde\u63a5<\/p>\n<p>\u8bfb\u53d6\u5ba2\u6237\u7aef\u8bf7\u6c42<\/p>\n<p>\u8c03\u7528\u4e1a\u52a1Handler<\/p>\n<p>\u53d1\u9001\u54cd\u5e94<\/p>\n<p>\u5173\u95ed\u8fde\u63a5<\/p>\n<p>\u6700\u7ec8\u5f62\u6210&#xff1a;<\/p>\n<p>select\u7b49\u5f85<br \/>\n      |<br \/>\n      v<br \/>\n\u76d1\u542cSocket\u5c31\u7eea&#xff1f;<br \/>\n      |<br \/>\n      &#043;&#8212;- \u662f \u2192 accept\u65b0\u5ba2\u6237\u7aef<br \/>\n      |<br \/>\n      &#043;&#8212;- \u5426 \u2192 \u5ba2\u6237\u7aefSocket\u5c31\u7eea<br \/>\n                    |<br \/>\n                    v<br \/>\n                   recv<br \/>\n                    |<br \/>\n                    v<br \/>\n                 \u4e1a\u52a1\u5904\u7406<br \/>\n                    |<br \/>\n                    v<br \/>\n                   send<\/p>\n<p>\u5230\u8fd9\u91cc&#xff0c;\u6211\u4eec\u5c31\u80fd\u591f\u4ece\u63a5\u53e3\u3001\u4f4d\u56fe\u3001\u4e8b\u4ef6\u673a\u5236\u4ee5\u53ca\u5b8c\u6574\u7a0b\u5e8f\u5b9e\u73b0\u56db\u4e2a\u65b9\u9762\u7406\u89e3select\u3002<\/p>\n<p>\u63a5\u4e0b\u6765\u7ee7\u7eed\u5b66\u4e60&#xff1a;<\/p>\n<p>poll\u4e0eepoll\u3002<\/p>\n<p>\u5c31\u80fd\u591f\u8fdb\u4e00\u6b65\u5206\u6790\u4e0d\u540cI\/O\u591a\u8def\u8f6c\u63a5\u673a\u5236\u5728\u63cf\u8ff0\u7b26\u7ba1\u7406\u3001\u5c31\u7eea\u4e8b\u4ef6\u901a\u77e5\u548c\u5927\u89c4\u6a21\u5e76\u53d1\u573a\u666f\u4e2d\u7684\u533a\u522b\u3002<\/p>\n<hr \/>\n","protected":false},"excerpt":{"rendered":"<p>Linux\u7f51\u7edc\u7f16\u7a0b&#xff1a;\u5f7b\u5e95\u7406\u89e3IO\u591a\u8def\u590d\u7528select&#xff01;\u4ecefd_set\u4f4d\u56fe\u3001\u8bfb\u5199\u5c31\u7eea\u5230\u624b\u5199TCP\u591a\u5ba2\u6237\u7aef\u5b57\u5178\u670d\u52a1\u5668 &#x1f525; \u661f\u6052\u968f\u98ce&#xff1a;\u4e2a\u4eba\u4e3b\u9875\u2744\ufe0f \u4e2a\u4eba\u4e13\u680f&#xff1a;\u300aLinux\u7f51\u7edc\u7f16\u7a0b\u4ece0\u52301\u300b&#xff5c;\u300aC\u8bed\u8a00\u57fa\u7840\u300b&#xff5c;\u300a\u6570\u636e\u7ed3\u6784\u300b&#xff5c;\u300a\u673a\u5668\u5b66\u4e60\u5bfc\u8bba\u300b&#xff5c;\u300a\u524d\u7aef\u57fa\u7840\u300b&#xff5c; \u300apython\u57fa\u7840\u300b&#xff5c; \u300aC\u4ece\u5165\u95e8\u5230\u5165\u571f\u300b&#xff5c; \u300aLinux\u7684\u5b66<\/p>\n","protected":false},"author":2,"featured_media":123011,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[11820,58,43,78],"topic":[],"class_list":["post-123019","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-server","tag-atomgit","tag-linux","tag-43","tag-78"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v20.3 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ 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content=\"Linux\u7f51\u7edc\u7f16\u7a0b&#xff1a;\u5f7b\u5e95\u7406\u89e3IO\u591a\u8def\u590d\u7528select&#xff01;\u4ecefd_set\u4f4d\u56fe\u3001\u8bfb\u5199\u5c31\u7eea\u5230\u624b\u5199TCP\u591a\u5ba2\u6237\u7aef\u5b57\u5178\u670d\u52a1\u5668 &#x1f525; \u661f\u6052\u968f\u98ce&#xff1a;\u4e2a\u4eba\u4e3b\u9875\u2744\ufe0f \u4e2a\u4eba\u4e13\u680f&#xff1a;\u300aLinux\u7f51\u7edc\u7f16\u7a0b\u4ece0\u52301\u300b&#xff5c;\u300aC\u8bed\u8a00\u57fa\u7840\u300b&#xff5c;\u300a\u6570\u636e\u7ed3\u6784\u300b&#xff5c;\u300a\u673a\u5668\u5b66\u4e60\u5bfc\u8bba\u300b&#xff5c;\u300a\u524d\u7aef\u57fa\u7840\u300b&#xff5c; \u300apython\u57fa\u7840\u300b&#xff5c; \u300aC\u4ece\u5165\u95e8\u5230\u5165\u571f\u300b&#xff5c; \u300aLinux\u7684\u5b66\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.wsisp.com\/helps\/123019.html\" \/>\n<meta property=\"og:site_name\" content=\"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"article:published_time\" content=\"2026-11-06T00:18:26+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/11\/20261106001814-6aed1cc6db5f3.png\" \/>\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=\"23 \u5206\" \/>\n<script type=\"application\/ld+json\" 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