{"id":76312,"date":"2026-02-22T07:25:30","date_gmt":"2026-02-21T23:25:30","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/76312.html"},"modified":"2026-02-22T07:25:30","modified_gmt":"2026-02-21T23:25:30","slug":"%e3%80%90linux%e3%80%91select-%e5%a4%9a%e8%b7%af%e8%bd%ac%e6%8e%a5%e6%b7%b1%e5%ba%a6%e5%89%96%e6%9e%90%ef%bc%9a%e4%bb%8e%e4%bd%8d%e5%9b%be%e5%8e%9f%e7%90%86%e5%88%b0%e5%ad%97%e5%85%b8%e6%9c%8d","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/76312.html","title":{"rendered":"\u3010Linux\u3011select \u591a\u8def\u8f6c\u63a5\u6df1\u5ea6\u5256\u6790\uff1a\u4ece\u4f4d\u56fe\u539f\u7406\u5230\u5b57\u5178\u670d\u52a1\u5668\u5b9e\u73b0"},"content":{"rendered":"<\/p>\n<h4>\u6587\u7ae0\u76ee\u5f55<\/h4>\n<ul>\n<li>\n<ul>\n<li><font face=\"\u6977\u4f53\" color=\"purple\" size=\"5\">select \u591a\u8def\u8f6c\u63a5\u6df1\u5ea6\u5256\u6790&#xff1a;\u4ece\u4f4d\u56fe\u539f\u7406\u5230\u5b57\u5178\u670d\u52a1\u5668\u5b9e\u73b0<\/font><\/li>\n<li><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u4e00\u3001select \u662f\u4ec0\u4e48&#xff1a;\u4e00\u4e2a&#034;\u73ed\u4e3b\u4efb&#034;\u7684\u6545\u4e8b<\/font><\/li>\n<li>\n<ul>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">1.1 \u95ee\u9898\u5f15\u5165&#xff1a;\u4e3a\u4ec0\u4e48\u9700\u8981 select&#xff1f;<\/font><\/li>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">1.2 \u73ed\u4e3b\u4efb\u7c7b\u6bd4<\/font><\/li>\n<\/ul>\n<\/li>\n<li><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u4e8c\u3001select \u51fd\u6570\u8be6\u89e3<\/font><\/li>\n<li>\n<ul>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">2.1 \u51fd\u6570\u539f\u578b<\/font><\/li>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">2.2 \u53c2\u6570\u8be6\u89e3<\/font><\/li>\n<li>\n<ul>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#336699\">\u53c2\u6570\u4e00&#xff1a;nfds<\/font><\/li>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#336699\">\u53c2\u6570\u4e8c\/\u4e09\/\u56db&#xff1a;readfds\u3001writefds\u3001exceptfds<\/font><\/li>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#336699\">\u53c2\u6570\u4e94&#xff1a;timeout<\/font><\/li>\n<\/ul>\n<\/li>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">2.3 \u8fd4\u56de\u503c<\/font><\/li>\n<\/ul>\n<\/li>\n<li><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u4e09\u3001fd_set&#xff1a;\u7406\u89e3\u4f4d\u56fe\u624d\u80fd\u7406\u89e3 select<\/font><\/li>\n<li>\n<ul>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">3.1 fd_set \u7684\u672c\u8d28<\/font><\/li>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">3.2 \u64cd\u4f5c fd_set \u7684\u56db\u4e2a\u5b8f<\/font><\/li>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">3.3 fd_set \u7684\u5927\u5c0f\u9650\u5236<\/font><\/li>\n<\/ul>\n<\/li>\n<li><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u56db\u3001select \u7684\u6267\u884c\u8fc7\u7a0b&#xff1a;\u4e00\u6b65\u6b65\u62c6\u89e3<\/font><\/li>\n<li>\n<ul>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">4.1 \u5b8c\u6574\u6267\u884c\u6d41\u7a0b<\/font><\/li>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">4.2 \u5173\u952e\u9677\u9631&#xff1a;select \u8fd4\u56de\u540e\u5fc5\u987b\u91cd\u5efa\u96c6\u5408<\/font><\/li>\n<\/ul>\n<\/li>\n<li><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u4e94\u3001socket \u5c31\u7eea\u6761\u4ef6<\/font><\/li>\n<li>\n<ul>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">5.1 \u4ec0\u4e48\u65f6\u5019\u7b97&#034;\u8bfb\u5c31\u7eea&#034;&#xff1f;<\/font><\/li>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">5.2 \u4ec0\u4e48\u65f6\u5019\u7b97&#034;\u5199\u5c31\u7eea&#034;&#xff1f;<\/font><\/li>\n<\/ul>\n<\/li>\n<li><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u516d\u3001select \u7684\u4f18\u7f3a\u70b9\u5206\u6790<\/font><\/li>\n<li>\n<ul>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">6.1 \u4f18\u70b9&#xff08;\u76f8\u6bd4\u963b\u585e IO&#xff09;<\/font><\/li>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">6.2 \u7f3a\u70b9&#xff08;\u9762\u8bd5\u5fc5\u95ee&#xff09;<\/font><\/li>\n<\/ul>\n<\/li>\n<li><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u4e03\u3001select \u5b9e\u6218\u4ee3\u7801<\/font><\/li>\n<li>\n<ul>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">7.1 \u6700\u7b80\u5355\u7684\u4f8b\u5b50&#xff1a;\u76d1\u63a7\u6807\u51c6\u8f93\u5165<\/font><\/li>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">7.2 \u6838\u5fc3\u5c01\u88c5\u7c7b&#xff1a;Selector<\/font><\/li>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">7.3 \u5b57\u5178\u670d\u52a1\u5668\u5b8c\u6574\u5b9e\u73b0<\/font><\/li>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">7.4 \u670d\u52a1\u5668\u5de5\u4f5c\u6d41\u7a0b\u56fe<\/font><\/li>\n<\/ul>\n<\/li>\n<li><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u516b\u3001select \u4f7f\u7528\u7684\u6ce8\u610f\u4e8b\u9879\u4e0e\u5e38\u89c1\u9519\u8bef<\/font><\/li>\n<li>\n<ul>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">8.1 \u5bb9\u6613\u72af\u7684\u9519\u8bef\u6e05\u5355<\/font><\/li>\n<\/ul>\n<\/li>\n<li><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u4e5d\u3001\u603b\u7ed3\u4e0e\u5c55\u671b<\/font><\/li>\n<li>\n<ul>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">9.1 \u6838\u5fc3\u8981\u70b9<\/font><\/li>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">9.2 \u5bb9\u6613\u6df7\u6dc6\u7684\u70b9<\/font><\/li>\n<li><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">9.3 select vs poll vs epoll \u5feb\u901f\u5bf9\u6bd4&#xff08;\u5b8c\u6574\u7248\u7559\u540e\u9762\u8bb2&#xff09;<\/font><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h3><font face=\"\u6977\u4f53\" color=\"purple\" size=\"5\">select \u591a\u8def\u8f6c\u63a5\u6df1\u5ea6\u5256\u6790&#xff1a;\u4ece\u4f4d\u56fe\u539f\u7406\u5230\u5b57\u5178\u670d\u52a1\u5668\u5b9e\u73b0<\/font><\/h3>\n<p>&#x1f4ac; \u5f00\u7bc7&#xff1a;\u4e0a\u4e00\u7bc7\u6211\u4eec\u641e\u61c2\u4e86\u4e94\u79cd IO \u6a21\u578b&#xff0c;\u77e5\u9053\u4e86 IO \u591a\u8def\u8f6c\u63a5\u662f\u9ad8\u5e76\u53d1\u670d\u52a1\u5668\u7684\u6838\u5fc3\u3002\u8fd9\u4e00\u7bc7\u6211\u4eec\u6765\u8ba4\u8bc6\u6700\u53e4\u8001\u7684\u591a\u8def\u8f6c\u63a5\u5b9e\u73b0\u2014\u2014select\u3002\u5b83\u8bde\u751f\u4e8e\u4e0a\u4e16\u7eaa 80 \u5e74\u4ee3&#xff0c;\u81f3\u4eca\u4ecd\u88ab\u5e7f\u6cdb\u6559\u5b66&#xff0c;\u539f\u56e0\u5f88\u7b80\u5355&#xff1a;\u641e\u61c2\u4e86 select&#xff0c;\u624d\u80fd\u771f\u6b63\u7406\u89e3\u4e3a\u4ec0\u4e48\u9700\u8981 epoll\u3002\u6211\u4eec\u4f1a\u4ece select \u7684\u63a5\u53e3\u5f00\u59cb&#xff0c;\u6df1\u6316\u4f4d\u56fe\u7684\u5de5\u4f5c\u539f\u7406&#xff0c;\u5206\u6790 socket \u7684\u5404\u79cd\u5c31\u7eea\u6761\u4ef6&#xff0c;\u6700\u540e\u7528 select \u5b9e\u73b0\u4e00\u4e2a\u5b8c\u6574\u7684\u5b57\u5178\u670d\u52a1\u5668\u3002\u5b66\u5b8c\u8fd9\u7bc7&#xff0c;\u4f60\u4e0d\u4ec5\u4f1a\u7528 select&#xff0c;\u66f4\u80fd\u6e05\u695a\u5730\u8bf4\u51fa\u5b83\u7684\u6bcf\u4e00\u4e2a\u7f3a\u9677&#xff0c;\u4ee5\u53ca epoll \u662f\u5982\u4f55\u9488\u5bf9\u6027\u5730\u89e3\u51b3\u8fd9\u4e9b\u7f3a\u9677\u7684\u3002<\/p>\n<p>&#x1f44d; \u70b9\u8d5e\u3001\u6536\u85cf\u4e0e\u5206\u4eab&#xff1a;select \u662f\u9762\u8bd5\u4e2d IO \u591a\u8def\u8f6c\u63a5\u7684\u5165\u95e8\u8003\u70b9&#xff0c;\u4e5f\u662f\u7406\u89e3 poll\/epoll \u7684\u53c2\u7167\u7cfb\u3002<\/p>\n<p>&#x1f680; \u5faa\u5e8f\u6e10\u8fdb&#xff1a;\u63a5\u53e3\u89e3\u6790 \u2192 \u4f4d\u56fe\u539f\u7406 \u2192 \u6267\u884c\u8fc7\u7a0b \u2192 \u5c31\u7eea\u6761\u4ef6 \u2192 \u4f18\u7f3a\u70b9 \u2192 \u5b57\u5178\u670d\u52a1\u5668\u5b8c\u6574\u5b9e\u73b0\u3002<\/p>\n<hr \/>\n<h3><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u4e00\u3001select \u662f\u4ec0\u4e48&#xff1a;\u4e00\u4e2a&#034;\u73ed\u4e3b\u4efb&#034;\u7684\u6545\u4e8b<\/font><\/h3>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">1.1 \u95ee\u9898\u5f15\u5165&#xff1a;\u4e3a\u4ec0\u4e48\u9700\u8981 select&#xff1f;<\/font><\/h4>\n<p>\u573a\u666f&#xff1a;\u4f60\u7684\u670d\u52a1\u5668\u9700\u8981\u540c\u65f6\u5904\u7406 100 \u4e2a\u5ba2\u6237\u7aef\u8fde\u63a5\u3002<\/p>\n<p>\u95ee\u9898&#xff1a;\u5982\u679c\u7528\u963b\u585e IO&#xff0c;read(client_fd) \u4f1a\u4e00\u76f4\u7b49\u8fd9\u4e2a\u5ba2\u6237\u7aef\u53d1\u6570\u636e&#xff0c;\u671f\u95f4\u5176\u4ed6 99 \u4e2a\u5ba2\u6237\u7aef\u6765\u4e86\u6570\u636e\u4e5f\u6ca1\u6cd5\u5904\u7406\u3002\u5f00 100 \u4e2a\u7ebf\u7a0b&#xff1f;\u592a\u6d6a\u8d39\u4e86\u3002<\/p>\n<p>\u89e3\u51b3\u65b9\u6848&#xff1a;select\u2014\u2014\u8ba9\u4e00\u4e2a\u8fdb\u7a0b\/\u7ebf\u7a0b\u540c\u65f6\u76d1\u89c6\u591a\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26&#xff0c;\u53ea\u8981\u6709\u4efb\u4f55\u4e00\u4e2a\u5c31\u7eea&#xff0c;\u5c31\u8fd4\u56de\u6765\u5904\u7406\u3002<\/p>\n<hr \/>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">1.2 \u73ed\u4e3b\u4efb\u7c7b\u6bd4<\/font><\/h4>\n<p>\u628a select \u60f3\u8c61\u6210\u73ed\u4e3b\u4efb\u7ba1\u7406\u73ed\u7ea7&#xff1a;<\/p>\n<ul>\n<li>100 \u4e2a\u5b66\u751f &#061; 100 \u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26<\/li>\n<li>\u5b66\u751f\u4e3e\u624b &#061; \u6587\u4ef6\u63cf\u8ff0\u7b26\u5c31\u7eea&#xff08;\u6709\u6570\u636e\u53ef\u8bfb\/\u53ef\u5199&#xff09;<\/li>\n<li>\u73ed\u4e3b\u4efb &#061; select<\/li>\n<li>\u73ed\u4e3b\u4efb\u95ee&#034;\u8c01\u6709\u95ee\u9898&#xff1f;&#034; &#061; \u8c03\u7528 select&#xff0c;\u7b49\u5f85<\/li>\n<\/ul>\n<p>\u6709\u4e24\u79cd\u7ba1\u7406\u65b9\u5f0f&#xff1a;<\/p>\n<p>\u65b9\u5f0f\u4e00&#xff08;\u6ca1\u6709 select&#xff09;&#xff1a;\u73ed\u4e3b\u4efb\u6328\u4e2a\u8d70\u5230\u6bcf\u4e2a\u5b66\u751f\u65c1\u8fb9\u7b49\u7740&#xff0c;\u7b49\u5b66\u751f1 \u56de\u7b54\u5b8c&#xff0c;\u518d\u53bb\u7b49\u5b66\u751f2\u2026\u2026\u6548\u7387\u6781\u4f4e\u3002<\/p>\n<p>\u65b9\u5f0f\u4e8c&#xff08;\u6709 select&#xff09;&#xff1a;\u73ed\u4e3b\u4efb\u7ad9\u5728\u8bb2\u53f0\u4e0a\u95ee&#034;\u8c01\u6709\u95ee\u9898&#xff1f;&#034;\u6709\u95ee\u9898\u7684\u5b66\u751f\u4e3e\u624b&#xff0c;\u73ed\u4e3b\u4efb\u9010\u4e00\u5904\u7406\u4e3e\u624b\u7684\u5b66\u751f&#xff0c;\u6ca1\u4e3e\u624b\u7684\u4e0d\u7ba1\u3002<\/p>\n<p>\u8fd9\u5c31\u662f select&#xff1a;\u4e00\u6b21\u7b49\u5f85&#xff0c;\u5904\u7406\u6240\u6709\u5c31\u7eea\u7684 fd\u3002<\/p>\n<hr \/>\n<h3><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u4e8c\u3001select \u51fd\u6570\u8be6\u89e3<\/font><\/h3>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">2.1 \u51fd\u6570\u539f\u578b<\/font><\/h4>\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><span class=\"token keyword\">int<\/span> <span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><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<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u4e4d\u4e00\u770b\u53c2\u6570\u5f88\u591a&#xff0c;\u5176\u5b9e\u903b\u8f91\u975e\u5e38\u6e05\u6670\u3002\u6211\u4eec\u9010\u4e2a\u62c6\u89e3&#xff1a;<\/p>\n<hr \/>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">2.2 \u53c2\u6570\u8be6\u89e3<\/font><\/h4>\n<h5><font face=\"\u6977\u4f53\" size=\"4\" color=\"#336699\">\u53c2\u6570\u4e00&#xff1a;nfds<\/font><\/h5>\n<p><span class=\"token keyword\">int<\/span> nfds<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u9700\u8981\u76d1\u89c6\u7684\u6700\u5927\u6587\u4ef6\u63cf\u8ff0\u7b26\u503c &#043; 1<\/span><\/p>\n<p>\u6bd4\u5982\u4f60\u76d1\u63a7 fd &#061; 3\u30015\u30017&#xff0c;\u90a3\u4e48 nfds &#061; 7 &#043; 1 &#061; 8\u3002<\/p>\n<p>\u4e3a\u4ec0\u4e48\u8981 &#043;1&#xff1f;\u56e0\u4e3a\u5185\u6838\u904d\u5386\u7684\u8303\u56f4\u662f [0, nfds)&#xff0c;\u4e0d\u5305\u62ec nfds \u672c\u8eab\u3002<\/p>\n<p>\u6280\u5de7&#xff1a;\u7ef4\u62a4\u4e00\u4e2a max_fd \u53d8\u91cf&#xff0c;\u6bcf\u6b21\u6709\u65b0 fd \u52a0\u5165\u65f6\u66f4\u65b0\u5b83&#xff0c;\u8c03\u7528 select \u65f6\u4f20 max_fd &#043; 1\u3002<\/p>\n<hr \/>\n<h5><font face=\"\u6977\u4f53\" size=\"4\" color=\"#336699\">\u53c2\u6570\u4e8c\/\u4e09\/\u56db&#xff1a;readfds\u3001writefds\u3001exceptfds<\/font><\/h5>\n<p>fd_set <span class=\"token operator\">*<\/span>readfds<span class=\"token punctuation\">;<\/span>    <span class=\"token comment\">\/\/ \u5173\u6ce8&#034;\u53ef\u8bfb&#034;\u7684 fd \u96c6\u5408<\/span><br \/>\nfd_set <span class=\"token operator\">*<\/span>writefds<span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ \u5173\u6ce8&#034;\u53ef\u5199&#034;\u7684 fd \u96c6\u5408  <\/span><br \/>\nfd_set <span class=\"token operator\">*<\/span>exceptfds<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u5173\u6ce8&#034;\u5f02\u5e38&#034;\u7684 fd \u96c6\u5408&#xff08;\u901a\u5e38\u4f20 NULL&#xff09;<\/span><\/p>\n<p>\u8fd9\u4e09\u4e2a\u53c2\u6570\u662f\u8f93\u5165\u8f93\u51fa\u578b\u53c2\u6570&#xff1a;<\/p>\n<ul>\n<li>\u8f93\u5165&#xff1a;\u4f60\u544a\u8bc9 select&#xff0c;\u54ea\u4e9b fd \u9700\u8981\u76d1\u63a7<\/li>\n<li>\u8f93\u51fa&#xff1a;select \u8fd4\u56de\u540e&#xff0c;\u8fd9\u4e09\u4e2a\u96c6\u5408\u91cc\u53ea\u4fdd\u7559\u5c31\u7eea\u7684 fd&#xff0c;\u672a\u5c31\u7eea\u7684\u88ab\u6e05\u96f6<\/li>\n<\/ul>\n<p>\u91cd\u8981&#xff1a;\u8fd9\u5c31\u662f select \u7684\u4e00\u4e2a\u5927\u7f3a\u9677\u2014\u2014\u6bcf\u6b21\u8c03\u7528 select \u524d&#xff0c;\u90fd\u8981\u91cd\u65b0\u8bbe\u7f6e\u8fd9\u4e09\u4e2a\u96c6\u5408\u3002\u56e0\u4e3a select \u8fd4\u56de\u540e&#xff0c;\u539f\u6765\u7684\u96c6\u5408\u5df2\u7ecf\u88ab\u4fee\u6539\u4e86\u3002<\/p>\n<hr \/>\n<h5><font face=\"\u6977\u4f53\" size=\"4\" color=\"#336699\">\u53c2\u6570\u4e94&#xff1a;timeout<\/font><\/h5>\n<p><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">timeval<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">long<\/span> tv_sec<span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ \u79d2<\/span><br \/>\n    <span class=\"token keyword\">long<\/span> tv_usec<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u5fae\u79d2<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u4e09\u79cd\u53d6\u503c&#xff1a;<\/p>\n<table>\n<tr>timeout \u503c\u884c\u4e3a<\/tr>\n<tbody>\n<tr>\n<td>NULL<\/td>\n<td>\u65e0\u9650\u7b49\u5f85&#xff0c;\u76f4\u5230\u6709 fd \u5c31\u7eea<\/td>\n<\/tr>\n<tr>\n<td>{0, 0}&#xff08;\u96f6\u503c&#xff09;<\/td>\n<td>\u7acb\u5373\u8fd4\u56de&#xff0c;\u53ea\u68c0\u67e5\u5f53\u524d\u72b6\u6001&#xff0c;\u4e0d\u7b49\u5f85<\/td>\n<\/tr>\n<tr>\n<td>\u6307\u5b9a\u65f6\u95f4\u503c<\/td>\n<td>\u7b49\u5f85\u6700\u591a\u8fd9\u4e48\u957f\u65f6\u95f4&#xff0c;\u8d85\u65f6\u8fd4\u56de 0<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">2.3 \u8fd4\u56de\u503c<\/font><\/h4>\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><br \/>\n<span class=\"token comment\">\/\/ ret &gt; 0&#xff1a;\u5c31\u7eea\u7684 fd \u4e2a\u6570&#xff08;\u6240\u6709\u96c6\u5408\u4e2d\u5c31\u7eea fd \u7684\u603b\u548c&#xff09;<\/span><br \/>\n<span class=\"token comment\">\/\/ ret &#061;&#061; 0&#xff1a;\u8d85\u65f6&#xff0c;\u6ca1\u6709 fd \u5c31\u7eea<\/span><br \/>\n<span class=\"token comment\">\/\/ ret &lt; 0&#xff1a;\u51fa\u9519&#xff0c;\u67e5\u770b errno<\/span><\/p>\n<hr \/>\n<h3><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u4e09\u3001fd_set&#xff1a;\u7406\u89e3\u4f4d\u56fe\u624d\u80fd\u7406\u89e3 select<\/font><\/h3>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">3.1 fd_set \u7684\u672c\u8d28<\/font><\/h4>\n<p>fd_set \u4e0d\u662f\u4ec0\u4e48\u9ad8\u6df1\u7684\u6570\u636e\u7ed3\u6784&#xff0c;\u5b83\u5c31\u662f\u4e00\u4e2a\u6574\u6570\u6570\u7ec4&#xff0c;\u672c\u8d28\u662f\u4f4d\u56fe&#xff08;bitmap&#xff09;\u3002<\/p>\n<p>\u4f4d\u56fe\u7684\u601d\u60f3&#xff1a;\u7528\u6bcf\u4e2a\u4e8c\u8fdb\u5236\u4f4d&#xff08;bit&#xff09;\u5bf9\u5e94\u4e00\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26\u3002<\/p>\n<p>fd_set&#xff08;\u7b80\u5316\u4e3a <span class=\"token number\">8<\/span> \u4f4d\u65b9\u4fbf\u8bf4\u660e&#xff09;&#xff1a;<\/p>\n<p>bit \u4f4d:  <span class=\"token number\">7<\/span>  <span class=\"token number\">6<\/span>  <span class=\"token number\">5<\/span>  <span class=\"token number\">4<\/span>  <span class=\"token number\">3<\/span>  <span class=\"token number\">2<\/span>  <span class=\"token number\">1<\/span>  <span class=\"token number\">0<\/span><br \/>\nfd \u53f7:   <span class=\"token number\">7<\/span>  <span class=\"token number\">6<\/span>  <span class=\"token number\">5<\/span>  <span class=\"token number\">4<\/span>  <span class=\"token number\">3<\/span>  <span class=\"token number\">2<\/span>  <span class=\"token number\">1<\/span>  <span class=\"token number\">0<\/span><br \/>\n\u503c:      <span class=\"token number\">0<\/span>  <span class=\"token number\">0<\/span>  <span class=\"token number\">0<\/span>  <span class=\"token number\">0<\/span>  <span class=\"token number\">0<\/span>  <span class=\"token number\">0<\/span>  <span class=\"token number\">0<\/span>  <span class=\"token number\">0<\/span>   \u2190 \u521d\u59cb\u5168 <span class=\"token number\">0<\/span><\/p>\n<p>\u60f3\u76d1\u63a7 fd&#061;2 \u548c fd&#061;5&#xff1a;<\/p>\n<p>bit \u4f4d:  <span class=\"token number\">7<\/span>  <span class=\"token number\">6<\/span>  <span class=\"token number\">5<\/span>  <span class=\"token number\">4<\/span>  <span class=\"token number\">3<\/span>  <span class=\"token number\">2<\/span>  <span class=\"token number\">1<\/span>  <span class=\"token number\">0<\/span><br \/>\n\u503c:      <span class=\"token number\">0<\/span>  <span class=\"token number\">0<\/span>  <span class=\"token number\">1<\/span>  <span class=\"token number\">0<\/span>  <span class=\"token number\">0<\/span>  <span class=\"token number\">1<\/span>  <span class=\"token number\">0<\/span>  <span class=\"token number\">0<\/span>   \u2190 <span class=\"token assign-left variable\">fd<\/span><span class=\"token operator\">&#061;<\/span><span class=\"token number\">5<\/span> \u548c <span class=\"token assign-left variable\">fd<\/span><span class=\"token operator\">&#061;<\/span><span class=\"token number\">2<\/span> \u5bf9\u5e94\u7684 bit \u7f6e <span class=\"token number\">1<\/span><\/p>\n<p>\u5c31\u8fd9\u4e48\u7b80\u5355&#xff01;\u54ea\u4e2a bit \u662f 1&#xff0c;\u5c31\u8868\u793a\u76d1\u63a7\u54ea\u4e2a fd\u3002<\/p>\n<hr \/>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">3.2 \u64cd\u4f5c fd_set \u7684\u56db\u4e2a\u5b8f<\/font><\/h4>\n<p><span class=\"token comment\">\/\/ \u6e05\u7a7a\u96c6\u5408&#xff1a;\u6240\u6709 bit \u7f6e 0<\/span><br \/>\n<span class=\"token keyword\">void<\/span> <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><span class=\"token comment\">\/\/ \u5c06 fd \u52a0\u5165\u96c6\u5408&#xff1a;\u628a fd \u5bf9\u5e94\u7684 bit \u7f6e 1<\/span><br \/>\n<span class=\"token keyword\">void<\/span> <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><span class=\"token comment\">\/\/ \u5c06 fd \u4ece\u96c6\u5408\u4e2d\u5220\u9664&#xff1a;\u628a fd \u5bf9\u5e94\u7684 bit \u7f6e 0<\/span><br \/>\n<span class=\"token keyword\">void<\/span> <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><span class=\"token comment\">\/\/ \u68c0\u67e5 fd \u662f\u5426\u5728\u96c6\u5408\u4e2d&#xff1a;\u68c0\u67e5 fd \u5bf9\u5e94\u7684 bit \u662f\u5426\u4e3a 1<\/span><br \/>\n<span class=\"token keyword\">int<\/span> <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>\u4f7f\u7528\u6a21\u5f0f\u51e0\u4e4e\u662f\u56fa\u5b9a\u7684&#xff1a;<\/p>\n<p>fd_set read_fds<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>          <span class=\"token comment\">\/\/ \u5148\u6e05\u7a7a<\/span><\/p>\n<p><span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>listen_fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ \u52a0\u5165\u8981\u76d1\u63a7\u7684 fd<\/span><br \/>\n<span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>client_fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<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>max_fd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">,<\/span> <span class=\"token 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\">\/\/ select \u8fd4\u56de\u540e&#xff0c;\u68c0\u67e5\u54ea\u4e9b fd \u5c31\u7eea<\/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>listen_fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token comment\">\/\/ listen_fd \u5c31\u7eea&#xff0c;\u6709\u65b0\u8fde\u63a5<\/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>client_fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token comment\">\/\/ client_fd \u5c31\u7eea&#xff0c;\u6709\u6570\u636e\u53ef\u8bfb<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<hr \/>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">3.3 fd_set \u7684\u5927\u5c0f\u9650\u5236<\/font><\/h4>\n<p>fd_set \u7684\u5927\u5c0f\u7531 FD_SETSIZE \u5b8f\u51b3\u5b9a&#xff0c;\u901a\u5e38\u662f 1024\u3002<\/p>\n<p>sizeof<span class=\"token punctuation\">(<\/span>fd_set<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">128<\/span> \u5b57\u8282 <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1024<\/span> bit<br \/>\n\u6bcf\u4e2a bit \u5bf9\u5e94\u4e00\u4e2a fd<br \/>\n\u2192 <span class=\"token keyword\">select<\/span> \u6700\u591a\u53ea\u80fd\u76d1\u63a7 <span class=\"token number\">1024<\/span> \u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26<\/p>\n<p>\u5728\u67d0\u4e9b\u7cfb\u7edf\u4e0a FD_SETSIZE &#061; 4096&#xff0c;\u4f46\u65e0\u8bba\u5982\u4f55&#xff0c;\u8fd9\u662f\u4e00\u4e2a\u56fa\u5b9a\u4e0a\u9650\u3002\u8fd9\u662f select \u7684\u786c\u4f24\u4e4b\u4e00\u3002<\/p>\n<hr \/>\n<h3><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u56db\u3001select \u7684\u6267\u884c\u8fc7\u7a0b&#xff1a;\u4e00\u6b65\u6b65\u62c6\u89e3<\/font><\/h3>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">4.1 \u5b8c\u6574\u6267\u884c\u6d41\u7a0b<\/font><\/h4>\n<p>\u6211\u4eec\u7528\u4e00\u4e2a\u5177\u4f53\u4f8b\u5b50\u6765\u8d70\u4e00\u904d select \u7684\u6267\u884c\u8fc7\u7a0b\u3002\u5047\u8bbe\u8981\u76d1\u63a7 fd&#061;1\u30012\u30015&#xff1a;<\/p>\n<p>\u7b2c\u4e00\u6b65&#xff1a;\u521d\u59cb\u5316<\/p>\n<p>fd_set set<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>     <span class=\"token comment\">\/\/ set: 00000000<\/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>set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ set: 00000010<\/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>set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ set: 00000110<\/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>set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ set: 00100110<\/span><\/p>\n<p>\u7b2c\u4e8c\u6b65&#xff1a;\u8c03\u7528 select<\/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 operator\">&amp;<\/span>set<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><br \/>\n<span class=\"token comment\">\/\/ nfds &#061; 5 &#043; 1 &#061; 6&#xff0c;\u5185\u6838\u76d1\u63a7 fd 0~5<\/span><\/p>\n<p>\u7b2c\u4e09\u6b65&#xff1a;\u5185\u6838\u7b49\u5f85<\/p>\n<p>\u5185\u6838\u62ff\u7740\u8fd9\u4e2a\u4f4d\u56fe&#xff0c;\u76d1\u63a7\u6bcf\u4e2a fd&#061;1 \u7684 fd \u7684\u72b6\u6001\u53d8\u5316\u3002\u6b64\u65f6\u7a0b\u5e8f\u963b\u585e\u5728 select \u8fd9\u91cc\u3002<\/p>\n<p>\u5185\u6838\u6b63\u5728\u7b49\u5f85\u4e2d<span class=\"token punctuation\">..<\/span>.<\/p>\n<p><span class=\"token assign-left variable\">fd<\/span><span class=\"token operator\">&#061;<\/span><span class=\"token number\">1<\/span>&#xff1a;\u7b49\u5f85<span class=\"token punctuation\">..<\/span>.<br \/>\n<span class=\"token assign-left variable\">fd<\/span><span class=\"token operator\">&#061;<\/span><span class=\"token number\">2<\/span>&#xff1a;\u7b49\u5f85<span class=\"token punctuation\">..<\/span>.<br \/>\n<span class=\"token assign-left variable\">fd<\/span><span class=\"token operator\">&#061;<\/span><span class=\"token number\">5<\/span>&#xff1a;\u7b49\u5f85<span class=\"token punctuation\">..<\/span>.<\/p>\n<p>\u7b2c\u56db\u6b65&#xff1a;fd&#061;1 \u548c fd&#061;2 \u5c31\u7eea<\/p>\n<p>\u5047\u8bbe fd&#061;1 \u548c fd&#061;2 \u90fd\u6709\u6570\u636e\u4e86&#xff1a;<\/p>\n<p>\u5185\u6838\u628a\u672a\u5c31\u7eea\u7684 <span class=\"token assign-left variable\">fd<\/span><span class=\"token operator\">&#061;<\/span><span class=\"token number\">5<\/span> \u4ece\u4f4d\u56fe\u4e2d\u6e05\u9664&#xff1a;<br \/>\nset: 00000110  \u2192 00000110 <span class=\"token punctuation\">(<\/span>fd<span class=\"token operator\">&#061;<\/span><span class=\"token number\">1<\/span>\u548cfd<span class=\"token operator\">&#061;<\/span><span class=\"token number\">2<\/span>\u4fdd\u7559&#xff0c;fd<span class=\"token operator\">&#061;<\/span><span class=\"token number\">5<\/span>\u88ab\u6e05\u96f6<span class=\"token punctuation\">)<\/span><\/p>\n<p>select \u8fd4\u56de&#xff0c;\u8fd4\u56de\u503c &#061; 2&#xff08;\u6709 2 \u4e2a fd \u5c31\u7eea&#xff09;<\/p>\n<p>\u7b2c\u4e94\u6b65&#xff1a;\u7528\u6237\u68c0\u67e5<\/p>\n<p><span class=\"token comment\">\/\/ select \u8fd4\u56de\u540e<\/span><br \/>\n<span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token comment\">\/* fd&#061;1 \u6709\u6570\u636e *\/<\/span> <span class=\"token punctuation\">}<\/span>   <span class=\"token comment\">\/\/ true<\/span><br \/>\n<span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">2<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token comment\">\/* fd&#061;2 \u6709\u6570\u636e *\/<\/span> <span class=\"token punctuation\">}<\/span>   <span class=\"token comment\">\/\/ true<\/span><br \/>\n<span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>set<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token comment\">\/* fd&#061;5 \u6709\u6570\u636e *\/<\/span> <span class=\"token punctuation\">}<\/span>   <span class=\"token comment\">\/\/ false&#xff01;\u88ab\u6e05\u96f6\u4e86<\/span><\/p>\n<hr \/>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">4.2 \u5173\u952e\u9677\u9631&#xff1a;select \u8fd4\u56de\u540e\u5fc5\u987b\u91cd\u5efa\u96c6\u5408<\/font><\/h4>\n<p><span class=\"token comment\">\/\/ \u274c \u9519\u8bef\u5199\u6cd5&#xff1a;\u53ea\u8c03\u7528\u4e00\u6b21 select<\/span><br \/>\nfd_set read_fds<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>fd1<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>fd2<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>fd3<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span>max_fd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">,<\/span> <span class=\"token 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><br \/>\n<span class=\"token comment\">\/\/ \u6b64\u65f6 read_fds \u5df2\u88ab\u4fee\u6539&#xff0c;\u672a\u5c31\u7eea\u7684 fd \u88ab\u6e05\u96f6\u4e86&#xff01;<\/span><br \/>\n<span class=\"token comment\">\/\/ \u4e0b\u6b21\u5faa\u73af\u65f6&#xff0c;read_fds \u91cc\u53ea\u5269\u672c\u6b21\u5c31\u7eea\u7684 fd<\/span><br \/>\n<span class=\"token comment\">\/\/ \u5176\u4ed6 fd \u6c38\u8fdc\u76d1\u63a7\u4e0d\u5230\u4e86<\/span><\/p>\n<p><span class=\"token comment\">\/\/ \u2705 \u6b63\u786e\u5199\u6cd5&#xff1a;\u6bcf\u6b21\u5faa\u73af\u91cd\u5efa\u96c6\u5408<\/span><br \/>\n<span class=\"token keyword\">int<\/span> fds<span class=\"token punctuation\">[<\/span>MAX<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u7528\u6570\u7ec4\u4fdd\u5b58\u6240\u6709\u9700\u8981\u76d1\u63a7\u7684 fd<\/span><br \/>\n<span class=\"token comment\">\/\/ &#8230;<\/span><br \/>\n<span class=\"token keyword\">for<\/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    fd_set read_fds<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token comment\">\/\/ \u6bcf\u6b21\u90fd\u91cd\u65b0\u4ece fds \u6570\u7ec4\u6784\u5efa\u96c6\u5408<\/span><br \/>\n    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> n<span class=\"token punctuation\">;<\/span> i<span class=\"token operator\">&#043;&#043;<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>fds<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/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>max_fd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">,<\/span> <span class=\"token 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><br \/>\n    <span class=\"token comment\">\/\/ \u5904\u7406\u5c31\u7eea\u4e8b\u4ef6&#8230;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u8fd9\u5c31\u662f\u4e3a\u4ec0\u4e48 select \u9700\u8981\u989d\u5916\u7ef4\u62a4\u4e00\u4e2a fd \u6570\u7ec4&#xff1a;select \u8fd4\u56de\u540e\u4f1a\u7834\u574f\u539f\u6709\u96c6\u5408&#xff0c;\u6240\u4ee5\u5fc5\u987b\u7528\u53e6\u4e00\u4e2a\u6570\u7ec4\u4fdd\u5b58\u6240\u6709\u9700\u8981\u76d1\u63a7\u7684 fd&#xff0c;\u6bcf\u6b21 select \u524d\u91cd\u5efa\u96c6\u5408\u3002<\/p>\n<hr \/>\n<h3><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u4e94\u3001socket \u5c31\u7eea\u6761\u4ef6<\/font><\/h3>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">5.1 \u4ec0\u4e48\u65f6\u5019\u7b97&#034;\u8bfb\u5c31\u7eea&#034;&#xff1f;<\/font><\/h4>\n<p>\u4e0b\u9762\u8fd9\u4e9b\u60c5\u51b5&#xff0c;select \u4f1a\u8ba4\u4e3a socket \u7684\u8bfb\u4e8b\u4ef6\u5c31\u7eea&#xff1a;<\/p>\n<table>\n<tr>\u60c5\u51b5\u8bf4\u660e<\/tr>\n<tbody>\n<tr>\n<td>\u63a5\u6536\u7f13\u51b2\u533a\u5b57\u8282\u6570 \u2265 \u4f4e\u6c34\u4f4d\u6807\u8bb0 SO_RCVLOWAT<\/td>\n<td>\u6b63\u5e38\u6709\u6570\u636e\u53ef\u8bfb&#xff0c;\u9ed8\u8ba4\u4f4e\u6c34\u4f4d\u662f 1 \u5b57\u8282<\/td>\n<\/tr>\n<tr>\n<td>\u5bf9\u7aef\u5173\u95ed\u8fde\u63a5<\/td>\n<td>read \u8fd4\u56de 0&#xff08;EOF&#xff09;<\/td>\n<\/tr>\n<tr>\n<td>\u76d1\u542c socket \u4e0a\u6709\u65b0\u8fde\u63a5<\/td>\n<td>accept \u4e0d\u4f1a\u963b\u585e<\/td>\n<\/tr>\n<tr>\n<td>socket \u4e0a\u6709\u672a\u5904\u7406\u7684\u9519\u8bef<\/td>\n<td>read \u8fd4\u56de -1&#xff0c;errno \u6709\u5177\u4f53\u9519\u8bef\u4fe1\u606f<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u751f\u6d3b\u7c7b\u6bd4&#xff1a;<br \/>\n  \u90ae\u7bb1\u91cc\u6709\u4fe1&#xff08;\u5b57\u8282\u6570\u591f&#xff09;\u2192 \u53ef\u4ee5\u53d6\u4fe1<br \/>\n  \u5bc4\u4fe1\u4eba\u8bf4<span class=\"token string\">&#034;\u4ee5\u540e\u4e0d\u53d1\u4e86&#034;<\/span>&#xff08;\u5bf9\u7aef\u5173\u95ed&#xff09;\u2192 \u77e5\u9053\u6ca1\u6709\u65b0\u4fe1\u4e86<br \/>\n  \u95e8\u53e3\u6709\u4eba\u6309\u95e8\u94c3&#xff08;\u65b0\u8fde\u63a5&#xff09;\u2192 \u53bb\u5f00\u95e8<br \/>\n  \u90ae\u7bb1\u574f\u4e86&#xff08;socket\u9519\u8bef&#xff09;\u2192 \u9700\u8981\u5904\u7406<\/p>\n<hr \/>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">5.2 \u4ec0\u4e48\u65f6\u5019\u7b97&#034;\u5199\u5c31\u7eea&#034;&#xff1f;<\/font><\/h4>\n<table>\n<tr>\u60c5\u51b5\u8bf4\u660e<\/tr>\n<tbody>\n<tr>\n<td>\u53d1\u9001\u7f13\u51b2\u533a\u53ef\u7528\u5b57\u8282\u6570 \u2265 \u4f4e\u6c34\u4f4d\u6807\u8bb0 SO_SNDLOWAT<\/td>\n<td>\u53ef\u4ee5\u5199\u5165\u6570\u636e&#xff0c;\u9ed8\u8ba4\u4f4e\u6c34\u4f4d\u662f 1 \u5b57\u8282<\/td>\n<\/tr>\n<tr>\n<td>socket \u7684\u5199\u64cd\u4f5c\u88ab\u5173\u95ed<\/td>\n<td>\u5199\u5165\u65f6\u89e6\u53d1 SIGPIPE \u4fe1\u53f7<\/td>\n<\/tr>\n<tr>\n<td>\u975e\u963b\u585e connect \u5b8c\u6210&#xff08;\u6210\u529f\u6216\u5931\u8d25&#xff09;<\/td>\n<td>\u9700\u8981\u901a\u8fc7 getsockopt \u68c0\u67e5\u662f\u5426\u6210\u529f<\/td>\n<\/tr>\n<tr>\n<td>socket \u4e0a\u6709\u672a\u8bfb\u53d6\u7684\u9519\u8bef<\/td>\n<td>\u540c\u4e0a<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u6ce8\u610f&#xff1a;\u4e00\u822c\u6765\u8bf4&#xff0c;\u53d1\u9001\u7f13\u51b2\u533a\u4e0d\u6ee1\u7684\u65f6\u5019\u5199\u5c31\u7eea\u603b\u662f\u6210\u7acb\u7684&#xff0c;\u6240\u4ee5\u901a\u5e38\u4e0d\u76d1\u63a7\u5199\u5c31\u7eea&#xff0c;\u9664\u975e\u53d1\u9001\u7f13\u51b2\u533a\u6ee1\u4e86&#xff08;\u6570\u636e\u53d1\u4e0d\u51fa\u53bb&#xff09;\u3002<\/p>\n<hr \/>\n<h3><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u516d\u3001select \u7684\u4f18\u7f3a\u70b9\u5206\u6790<\/font><\/h3>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">6.1 \u4f18\u70b9&#xff08;\u76f8\u6bd4\u963b\u585e IO&#xff09;<\/font><\/h4>\n<ul>\n<li>\u4e00\u4e2a\u7ebf\u7a0b\u76d1\u63a7\u591a\u4e2a fd&#xff1a;\u89e3\u51b3\u4e86&#034;\u4e00\u7ebf\u7a0b\u53ea\u80fd\u7b49\u4e00\u4e2a fd&#034;\u7684\u95ee\u9898<\/li>\n<li>\u8de8\u5e73\u53f0&#xff1a;\u51e0\u4e4e\u6240\u6709 POSIX \u7cfb\u7edf\u90fd\u652f\u6301 select<\/li>\n<\/ul>\n<hr \/>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">6.2 \u7f3a\u70b9&#xff08;\u9762\u8bd5\u5fc5\u95ee&#xff09;<\/font><\/h4>\n<p>select \u6709\u56db\u4e2a\u8457\u540d\u7f3a\u70b9&#xff1a;<\/p>\n<p>\u7f3a\u70b9 1&#xff1a;fd \u6570\u91cf\u6709\u4e0a\u9650<\/p>\n<p>FD_SETSIZE <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1024<\/span>&#xff08;\u591a\u6570\u7cfb\u7edf&#xff09;<br \/>\n\u2192 \u6700\u591a\u53ea\u80fd\u76d1\u63a7 <span class=\"token number\">1024<\/span> \u4e2a fd<br \/>\n\u2192 \u4e07\u7ea7\u5e76\u53d1\u6839\u672c\u4e0d\u591f\u7528<\/p>\n<p>\u7f3a\u70b9 2&#xff1a;\u6bcf\u6b21\u8c03\u7528\u90fd\u8981\u62f7\u8d1d\u6574\u4e2a fd_set<\/p>\n<p>\u7528\u6237\u6001 fd_set \u2500\u2500\u62f7\u8d1d\u2500\u2500<span class=\"token operator\">&gt;<\/span> \u5185\u6838\u6001<br \/>\n<span class=\"token punctuation\">(<\/span>\u6bcf\u6b21 <span class=\"token keyword\">select<\/span> \u90fd\u8981\u62f7\u8d1d&#xff0c;fd \u8d8a\u591a&#xff0c;\u62f7\u8d1d\u8d8a\u91cd<span class=\"token punctuation\">)<\/span><\/p>\n<p>\u7f3a\u70b9 3&#xff1a;\u5185\u6838\u9700\u8981\u904d\u5386\u6240\u6709 fd<\/p>\n<p><span class=\"token keyword\">select<\/span> \u8fd4\u56de\u540e&#xff0c;\u5185\u6838\u4e0d\u77e5\u9053\u54ea\u4e9b fd \u5c31\u7eea\u4e86<br \/>\n\u9700\u8981\u4ece <span class=\"token number\">0<\/span> \u904d\u5386\u5230 nfds&#xff0c;\u9010\u4e2a\u68c0\u67e5<br \/>\nO<span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span> \u590d\u6742\u5ea6&#xff0c;fd \u8d8a\u591a\u8d8a\u6162<\/p>\n<p>\u7f3a\u70b9 4&#xff1a;\u6bcf\u6b21\u8c03\u7528\u90fd\u8981\u624b\u52a8\u91cd\u5efa\u96c6\u5408<\/p>\n<p><span class=\"token keyword\">select<\/span> \u8fd4\u56de\u540e&#xff0c;fd_set \u88ab\u4fee\u6539\u4e86<br \/>\n\u5fc5\u987b\u7528\u989d\u5916\u6570\u7ec4\u4fdd\u5b58\u6240\u6709 fd&#xff0c;\u6bcf\u6b21\u91cd\u5efa<br \/>\n\u63a5\u53e3\u8bbe\u8ba1\u4e0d\u53cb\u597d<\/p>\n<p>\u7528\u4e00\u5f20\u8868\u5bf9\u6bd4\u4e00\u4e0b&#xff1a;<\/p>\n<table>\n<tr>\u95ee\u9898select \u7684\u5904\u7406epoll \u7684\u5904\u7406&#xff08;\u5267\u900f&#xff09;<\/tr>\n<tbody>\n<tr>\n<td>fd \u6570\u91cf<\/td>\n<td>\u4e0a\u9650 1024<\/td>\n<td>\u65e0\u4e0a\u9650<\/td>\n<\/tr>\n<tr>\n<td>fd \u4fe1\u606f\u4f20\u9012<\/td>\n<td>\u6bcf\u6b21\u5168\u91cf\u62f7\u8d1d\u5230\u5185\u6838<\/td>\n<td>\u53ea\u6ce8\u518c\u4e00\u6b21<\/td>\n<\/tr>\n<tr>\n<td>\u627e\u5c31\u7eea fd<\/td>\n<td>\u904d\u5386\u6240\u6709 fd&#xff0c;O(n)<\/td>\n<td>\u76f4\u63a5\u8fd4\u56de\u5c31\u7eea\u5217\u8868&#xff0c;O(1)<\/td>\n<\/tr>\n<tr>\n<td>\u96c6\u5408\u7ef4\u62a4<\/td>\n<td>\u6bcf\u6b21\u624b\u52a8\u91cd\u5efa<\/td>\n<td>\u5185\u6838\u7ef4\u62a4&#xff0c;\u81ea\u52a8<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<h3><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u4e03\u3001select \u5b9e\u6218\u4ee3\u7801<\/font><\/h3>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">7.1 \u6700\u7b80\u5355\u7684\u4f8b\u5b50&#xff1a;\u76d1\u63a7\u6807\u51c6\u8f93\u5165<\/font><\/h4>\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;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 punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    fd_set read_fds<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">for<\/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\">\/\/ \u6bcf\u6b21\u5faa\u73af\u90fd\u8981\u91cd\u5efa\u96c6\u5408&#xff01;<\/span><br \/>\n        <span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">0<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u76d1\u63a7 fd&#061;0&#xff08;\u6807\u51c6\u8f93\u5165&#xff09;<\/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\">\/\/ timeout &#061; NULL&#xff1a;\u65e0\u9650\u7b49\u5f85&#xff0c;\u76f4\u5230\u6807\u51c6\u8f93\u5165\u5c31\u7eea<\/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><span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">,<\/span> <span class=\"token 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 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> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;select&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>ret <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token comment\">\/\/ \u8d85\u65f6&#xff0c;\u4f46\u6211\u4eec timeout&#061;NULL \u6240\u4ee5\u4e0d\u4f1a\u5230\u8fd9\u91cc<\/span><br \/>\n            <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;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\">\/\/ select \u8fd4\u56de &gt; 0&#xff0c;\u68c0\u67e5\u662f\u8c01\u5c31\u7eea\u4e86<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">0<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">char<\/span> buf<span class=\"token punctuation\">[<\/span><span class=\"token number\">1024<\/span><span class=\"token punctuation\">]<\/span> <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 punctuation\">;<\/span><br \/>\n            <span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">0<\/span><span class=\"token punctuation\">,<\/span> buf<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buf<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#8211;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;input: %s&#034;<\/span><span class=\"token punctuation\">,<\/span> buf<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> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u8fd0\u884c\u6548\u679c&#xff1a;<\/p>\n<ul>\n<li>\u7a0b\u5e8f\u7b49\u5f85\u8f93\u5165<\/li>\n<li>\u4f60\u8f93\u5165\u4e00\u884c\u6587\u5b57&#xff0c;\u7a0b\u5e8f\u6253\u5370\u51fa\u6765<\/li>\n<li>\u6ca1\u6709\u8f93\u5165\u65f6\u4e0d\u5360\u7528 CPU&#xff08;\u4e0d\u50cf\u975e\u963b\u585e\u8f6e\u8be2&#xff09;<\/li>\n<\/ul>\n<hr \/>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">7.2 \u6838\u5fc3\u5c01\u88c5\u7c7b&#xff1a;Selector<\/font><\/h4>\n<p>\u5728\u5b9e\u73b0\u5b57\u5178\u670d\u52a1\u5668\u4e4b\u524d&#xff0c;\u6211\u4eec\u5148\u628a select \u7684\u4f7f\u7528\u5c01\u88c5\u6210\u4e00\u4e2a Selector \u7c7b&#xff0c;\u65b9\u4fbf\u4f7f\u7528&#xff1a;<\/p>\n<p><span class=\"token comment\">\/\/ selector.hpp<\/span><br \/>\n<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><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><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;cstdio&gt;<\/span><\/span><\/p>\n<p><span class=\"token comment\">\/\/ \u8f85\u52a9\u8c03\u8bd5\u51fd\u6570&#xff1a;\u6253\u5370\u5f53\u524d\u76d1\u63a7\u7684 fd \u5217\u8868<\/span><br \/>\n<span class=\"token keyword\">void<\/span> <span class=\"token function\">PrintFdSet<\/span><span class=\"token punctuation\">(<\/span>fd_set<span class=\"token operator\">*<\/span> fds<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">int<\/span> max_fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;select fds: &#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> max_fd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>i<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span>i<span class=\"token punctuation\">,<\/span> fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;%d &#034;<\/span><span class=\"token punctuation\">,<\/span> i<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 function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\\\\n&#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 comment\">\/\/ TcpSocket \u7c7b&#xff08;\u7b80\u5316\u7248&#xff0c;\u5b9e\u9645\u9879\u76ee\u4e2d\u66f4\u5b8c\u6574&#xff09;<\/span><br \/>\n<span class=\"token keyword\">class<\/span> <span class=\"token class-name\">TcpSocket<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">public<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token function\">TcpSocket<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">:<\/span> <span class=\"token function\">fd_<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token function\">TcpSocket<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">:<\/span> <span class=\"token function\">fd_<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">int<\/span> <span class=\"token function\">GetFd<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token keyword\">return<\/span> fd_<span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">bool<\/span> <span class=\"token function\">Socket<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        fd_ <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">socket<\/span><span class=\"token punctuation\">(<\/span>AF_INET<span class=\"token punctuation\">,<\/span> SOCK_STREAM<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> fd_ <span class=\"token operator\">&gt;&#061;<\/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 keyword\">bool<\/span> <span class=\"token function\">Bind<\/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> ip<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">uint16_t<\/span> port<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">sockaddr_in<\/span> addr<span class=\"token punctuation\">;<\/span><br \/>\n        addr<span class=\"token punctuation\">.<\/span>sin_family <span class=\"token operator\">&#061;<\/span> AF_INET<span class=\"token punctuation\">;<\/span><br \/>\n        addr<span class=\"token punctuation\">.<\/span>sin_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><br \/>\n        addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">.<\/span>s_addr <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">inet_addr<\/span><span class=\"token punctuation\">(<\/span>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><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token function\">bind<\/span><span class=\"token punctuation\">(<\/span>fd_<span class=\"token punctuation\">,<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">sockaddr<\/span><span class=\"token operator\">*<\/span><span class=\"token punctuation\">)<\/span><span class=\"token operator\">&amp;<\/span>addr<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">bool<\/span> <span class=\"token function\">Listen<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> backlog<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token function\">listen<\/span><span class=\"token punctuation\">(<\/span>fd_<span class=\"token punctuation\">,<\/span> backlog<span class=\"token punctuation\">)<\/span> <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><\/p>\n<p>    <span class=\"token keyword\">bool<\/span> <span class=\"token function\">Accept<\/span><span class=\"token punctuation\">(<\/span>TcpSocket<span class=\"token operator\">*<\/span> new_sock<span class=\"token punctuation\">,<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">*<\/span> ip <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">uint16_t<\/span><span class=\"token operator\">*<\/span> port <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">nullptr<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">sockaddr_in<\/span> client_addr<span class=\"token punctuation\">;<\/span><br \/>\n        socklen_t len <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>client_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">int<\/span> new_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">accept<\/span><span class=\"token punctuation\">(<\/span>fd_<span class=\"token punctuation\">,<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">sockaddr<\/span><span class=\"token operator\">*<\/span><span class=\"token punctuation\">)<\/span><span class=\"token operator\">&amp;<\/span>client_addr<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>len<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>new_fd <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        new_sock<span class=\"token operator\">-&gt;<\/span>fd_ <span class=\"token operator\">&#061;<\/span> new_fd<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>ip<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">*<\/span>ip <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">inet_ntoa<\/span><span class=\"token punctuation\">(<\/span>client_addr<span class=\"token punctuation\">.<\/span>sin_addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>port<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">*<\/span>port <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">ntohs<\/span><span class=\"token punctuation\">(<\/span>client_addr<span class=\"token punctuation\">.<\/span>sin_port<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token comment\">\/\/\u672c\u5b57\u5178\u670d\u52a1\u5668\u4e3a\u6559\u5b66\u6f14\u793a&#xff0c;\u4f7f\u7528\u201c\u4e00\u884c\u4e00\u4e2a\u8bf7\u6c42\u201d&#xff0c;\u5e76\u5047\u8bbe\u5355\u6b21 recv\/send \u8db3\u591f&#xff1b;\u751f\u4ea7\u9700\u5b9e\u73b0\u6d88\u606f\u8fb9\u754c&#xff08;\u5982 \\\\n \u5206\u9694\/\u56fa\u5b9a\u957f\u5ea6\/\u957f\u5ea6\u5b57\u6bb5&#xff09;\u4e0e\u5faa\u73af\u53d1\u9001\u3002<\/span><br \/>\n    <span class=\"token keyword\">bool<\/span> <span class=\"token function\">Recv<\/span><span class=\"token punctuation\">(<\/span>std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">*<\/span> buf<span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">char<\/span> tmp<span class=\"token punctuation\">[<\/span><span class=\"token number\">4096<\/span><span class=\"token punctuation\">]<\/span> <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 punctuation\">;<\/span><br \/>\n        ssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>fd_<span class=\"token punctuation\">,<\/span> tmp<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>tmp<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#8211;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&lt;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token operator\">*<\/span>buf <span class=\"token operator\">&#061;<\/span> tmp<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">bool<\/span> <span class=\"token function\">Send<\/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> buf<span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token function\">send<\/span><span class=\"token punctuation\">(<\/span>fd_<span class=\"token punctuation\">,<\/span> buf<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> buf<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&gt;<\/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 keyword\">void<\/span> <span class=\"token function\">Close<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>fd_ <span class=\"token operator\">&gt;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>fd_<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            fd_ <span class=\"token operator\">&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><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 keyword\">int<\/span> 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\">\/**<br \/>\n * Selector&#xff1a;\u5bf9 select \u7684\u5c01\u88c5<br \/>\n * \u6ce8\u610f&#xff1a;\u8fd9\u4e2a\u7c7b\u4fdd\u5b58 TcpSocket \u5bf9\u8c61&#xff0c;\u4f46\u4e0d\u8d1f\u8d23\u7ba1\u7406\u5185\u5b58<br \/>\n *\/<\/span><br \/>\n<span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Selector<\/span> <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 number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u5343\u4e07\u4e0d\u8981\u5fd8\u8bb0\u521d\u59cb\u5316&#xff01;&#xff01;&#xff01;<\/span><br \/>\n        <span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>read_fds_<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token comment\">\/**<br \/>\n     * \u5c06\u4e00\u4e2a socket \u52a0\u5165\u76d1\u63a7\u96c6\u5408<br \/>\n     *\/<\/span><br \/>\n    <span class=\"token keyword\">bool<\/span> <span class=\"token function\">Add<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> TcpSocket<span class=\"token operator\">&amp;<\/span> sock<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">int<\/span> fd <span class=\"token operator\">&#061;<\/span> sock<span class=\"token punctuation\">.<\/span><span class=\"token function\">GetFd<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;[Selector::Add] fd &#061; %d\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span> fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ \u68c0\u67e5\u662f\u5426\u5df2\u7ecf\u5728\u96c6\u5408\u4e2d<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>fd_map_<span class=\"token punctuation\">.<\/span><span class=\"token function\">find<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> fd_map_<span class=\"token punctuation\">.<\/span><span class=\"token function\">end<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;Add failed! fd %d already in Selector!\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span> fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        fd_map_<span class=\"token punctuation\">[<\/span>fd<span class=\"token punctuation\">]<\/span> <span class=\"token operator\">&#061;<\/span> sock<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds_<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ \u66f4\u65b0\u6700\u5927 fd<\/span><br \/>\n        <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> <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\">\/**<br \/>\n     * \u5c06\u4e00\u4e2a socket \u4ece\u76d1\u63a7\u96c6\u5408\u79fb\u9664<br \/>\n     *\/<\/span><br \/>\n    <span class=\"token keyword\">bool<\/span> <span class=\"token function\">Del<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> TcpSocket<span class=\"token operator\">&amp;<\/span> sock<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">int<\/span> fd <span class=\"token operator\">&#061;<\/span> sock<span class=\"token punctuation\">.<\/span><span class=\"token function\">GetFd<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;[Selector::Del] fd &#061; %d\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span> fd<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_map_<span class=\"token punctuation\">.<\/span><span class=\"token function\">find<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> fd_map_<span class=\"token punctuation\">.<\/span><span class=\"token function\">end<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;Del failed! fd %d not in Selector!\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span> fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        fd_map_<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><br \/>\n        <span class=\"token function\">FD_CLR<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds_<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ \u91cd\u65b0\u627e\u6700\u5927\u7684 fd&#xff08;\u4ece\u53f3\u5f80\u5de6\u627e\u6bd4\u8f83\u5feb&#xff09;<\/span><br \/>\n        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> max_fd_<span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&gt;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#8212;<\/span>i<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span>i<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds_<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                max_fd_ <span class=\"token operator\">&#061;<\/span> i<span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">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\">\/**<br \/>\n     * \u7b49\u5f85\u5c31\u7eea\u4e8b\u4ef6&#xff0c;\u8fd4\u56de\u5c31\u7eea\u7684 socket \u5217\u8868<br \/>\n     *<br \/>\n     * \u5173\u952e\u8bbe\u8ba1&#xff1a;\u5fc5\u987b\u521b\u5efa read_fds_ \u7684\u526f\u672c tmp \u4f20\u7ed9 select&#xff01;<br \/>\n     * \u539f\u56e0&#xff1a;select \u8fd4\u56de\u540e\u4f1a\u4fee\u6539\u4f20\u5165\u7684 fd_set&#xff0c;<br \/>\n     *       \u5982\u679c\u76f4\u63a5\u4f20 read_fds_&#xff0c;\u4e0b\u6b21\u5faa\u73af\u65f6\u76d1\u63a7\u96c6\u5408\u5c31\u4e22\u5931\u4e86<br \/>\n     *\/<\/span><br \/>\n    <span class=\"token keyword\">bool<\/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>TcpSocket<span class=\"token operator\">&gt;<\/span><span class=\"token operator\">*<\/span> output<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        output<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 comment\">\/\/ \u521b\u5efa\u526f\u672c&#xff01;&#xff01;&#xff01;\u8fd9\u662f\u5173\u952e<\/span><br \/>\n        fd_set tmp <span class=\"token operator\">&#061;<\/span> read_fds_<span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ \u8c03\u8bd5\u8f93\u51fa<\/span><br \/>\n        <span class=\"token function\">PrintFdSet<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>tmp<span class=\"token punctuation\">,<\/span> max_fd_<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token keyword\">int<\/span> nfds <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span>max_fd_ <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>tmp<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><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>nfds <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;select&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">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\">\/\/ \u904d\u5386\u6240\u6709\u53ef\u80fd\u7684 fd&#xff0c;\u68c0\u67e5\u54ea\u4e9b\u5c31\u7eea\u4e86<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u6ce8\u610f&#xff1a;\u5faa\u73af\u5230 max_fd_ &#043; 1&#xff0c;\u4e0d\u80fd\u591a\u5faa\u73af<\/span><br \/>\n        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> max_fd_ <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>i<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">FD_ISSET<\/span><span class=\"token punctuation\">(<\/span>i<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>tmp<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                output<span class=\"token operator\">-&gt;<\/span><span class=\"token function\">push_back<\/span><span class=\"token punctuation\">(<\/span>fd_map_<span class=\"token punctuation\">[<\/span>i<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 punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">private<\/span><span class=\"token operator\">:<\/span><br \/>\n    fd_set read_fds_<span class=\"token punctuation\">;<\/span>                          <span class=\"token comment\">\/\/ \u4fdd\u5b58\u5b8c\u6574\u7684\u76d1\u63a7\u96c6\u5408<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> max_fd_<span class=\"token punctuation\">;<\/span>                               <span class=\"token comment\">\/\/ \u5f53\u524d\u6700\u5927\u7684 fd \u503c<\/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> TcpSocket<span class=\"token operator\">&gt;<\/span> fd_map_<span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ fd \u5230 socket \u5bf9\u8c61\u7684\u6620\u5c04&#xff0c;\u4e3a\u7b80\u5316\u6f14\u793a&#xff0c;\u8fd9\u91cc\u7528\u503c\u5b58\u50a8&#xff0c;\u751f\u4ea7\u5efa\u8bae\u7edf\u4e00\u7ba1\u7406 fd \u751f\u547d\u5468\u671f<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<hr \/>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">7.3 \u5b57\u5178\u670d\u52a1\u5668\u5b8c\u6574\u5b9e\u73b0<\/font><\/h4>\n<p>\u5b57\u5178\u670d\u52a1\u5668&#xff1a;\u5ba2\u6237\u7aef\u53d1\u4e00\u4e2a\u82f1\u6587\u5355\u8bcd&#xff0c;\u670d\u52a1\u5668\u8fd4\u56de\u5176\u4e2d\u6587\u7ffb\u8bd1\u3002<\/p>\n<p><span class=\"token comment\">\/\/ tcp_select_server.hpp<\/span><br \/>\n<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><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><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;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;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;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;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\">&#034;selector.hpp&#034;<\/span><\/span><\/p>\n<p><span class=\"token comment\">\/\/ \u4e1a\u52a1\u5904\u7406\u51fd\u6570\u7c7b\u578b&#xff1a;\u8f93\u5165\u8bf7\u6c42&#xff0c;\u8f93\u51fa\u54cd\u5e94<\/span><br \/>\n<span class=\"token keyword\">typedef<\/span> std<span class=\"token double-colon punctuation\">::<\/span>function<span class=\"token operator\">&lt;<\/span><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> req<span class=\"token punctuation\">,<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">*<\/span> resp<span class=\"token punctuation\">)<\/span><span class=\"token operator\">&gt;<\/span> Handler<span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">TcpSelectServer<\/span> <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><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> <span class=\"token keyword\">uint16_t<\/span> port<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> <span class=\"token function\">port_<\/span><span class=\"token punctuation\">(<\/span>port<span class=\"token punctuation\">)<\/span> <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>Handler handler<span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/\/ 1. \u521b\u5efa\u76d1\u542c socket<\/span><br \/>\n        TcpSocket listen_sock<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>listen_sock<span class=\"token punctuation\">.<\/span><span class=\"token function\">Socket<\/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\">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\">\/\/ \u8bbe\u7f6e\u7aef\u53e3\u590d\u7528&#xff08;\u907f\u514d TIME_WAIT \u671f\u95f4\u65e0\u6cd5\u91cd\u542f&#xff09;<\/span><br \/>\n        <span class=\"token keyword\">int<\/span> opt <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">setsockopt<\/span><span class=\"token punctuation\">(<\/span>listen_sock<span class=\"token punctuation\">.<\/span><span class=\"token function\">GetFd<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> SOL_SOCKET<span class=\"token punctuation\">,<\/span> SO_REUSEADDR<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>opt<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>opt<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ 2. \u7ed1\u5b9a\u7aef\u53e3<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>listen_sock<span class=\"token punctuation\">.<\/span><span class=\"token function\">Bind<\/span><span class=\"token punctuation\">(<\/span>ip_<span class=\"token punctuation\">,<\/span> port_<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;bind&#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\">\/\/ 3. \u5f00\u59cb\u76d1\u542c<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>listen_sock<span class=\"token punctuation\">.<\/span><span class=\"token function\">Listen<\/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><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 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><span class=\"token string\">&#034;[Server] \u542f\u52a8\u6210\u529f&#xff0c;\u76d1\u542c %s:%d\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span> 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> port_<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ 4. \u521b\u5efa Selector&#xff0c;\u5c06 listen_sock \u52a0\u5165<\/span><br \/>\n        Selector selector<span class=\"token punctuation\">;<\/span><br \/>\n        selector<span class=\"token punctuation\">.<\/span><span class=\"token function\">Add<\/span><span class=\"token punctuation\">(<\/span>listen_sock<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ 5. \u8fdb\u5165\u4e8b\u4ef6\u5faa\u73af<\/span><br \/>\n        <span class=\"token keyword\">for<\/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            std<span class=\"token double-colon punctuation\">::<\/span>vector<span class=\"token operator\">&lt;<\/span>TcpSocket<span class=\"token operator\">&gt;<\/span> ready_socks<span class=\"token punctuation\">;<\/span><\/p>\n<p>            <span class=\"token comment\">\/\/ \u7b49\u5f85\u5c31\u7eea\u4e8b\u4ef6&#xff08;\u963b\u585e\u5728\u8fd9\u91cc&#xff09;<\/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\">Wait<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>ready_socks<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token comment\">\/\/ 6. \u5904\u7406\u6240\u6709\u5c31\u7eea\u7684 socket<\/span><br \/>\n            <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span>size_t i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> ready_socks<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>i<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><\/p>\n<p>                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>ready_socks<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">GetFd<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> listen_sock<span class=\"token punctuation\">.<\/span><span class=\"token function\">GetFd<\/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\">\/\/ 6.1 listen_sock \u5c31\u7eea \u2192 \u6709\u65b0\u8fde\u63a5\u5230\u6765<\/span><br \/>\n                    TcpSocket new_sock<span class=\"token punctuation\">;<\/span><br \/>\n                    std<span class=\"token double-colon punctuation\">::<\/span>string client_ip<span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token keyword\">uint16_t<\/span> client_port<span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>listen_sock<span class=\"token punctuation\">.<\/span><span class=\"token function\">Accept<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>new_sock<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>client_ip<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>client_port<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;accept&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;[Server] \u65b0\u8fde\u63a5&#xff1a;%s:%d (fd&#061;%d)\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                           client_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> client_port<span class=\"token punctuation\">,<\/span> new_sock<span class=\"token punctuation\">.<\/span><span class=\"token function\">GetFd<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token comment\">\/\/ \u5c06\u65b0\u8fde\u63a5\u52a0\u5165 selector \u76d1\u63a7<\/span><br \/>\n                    selector<span class=\"token punctuation\">.<\/span><span class=\"token function\">Add<\/span><span class=\"token punctuation\">(<\/span>new_sock<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    <span class=\"token comment\">\/\/ 6.2 \u666e\u901a socket \u5c31\u7eea \u2192 \u6709\u6570\u636e\u53ef\u8bfb<\/span><br \/>\n                    std<span class=\"token double-colon punctuation\">::<\/span>string req<span class=\"token punctuation\">,<\/span> resp<span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>ready_socks<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">Recv<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>req<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token comment\">\/\/ \u5ba2\u6237\u7aef\u65ad\u5f00\u8fde\u63a5<\/span><br \/>\n                        <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;[Server] \u5ba2\u6237\u7aef\u65ad\u5f00&#xff0c;fd&#061;%d\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span> ready_socks<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">GetFd<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        selector<span class=\"token punctuation\">.<\/span><span class=\"token function\">Del<\/span><span class=\"token punctuation\">(<\/span>ready_socks<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        ready_socks<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">Close<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">continue<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><\/p>\n<p>                    <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;[Server] \u6536\u5230\u8bf7\u6c42&#xff1a;%s\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span> req<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><span class=\"token punctuation\">;<\/span><\/p>\n<p>                    <span class=\"token comment\">\/\/ \u8c03\u7528\u4e1a\u52a1\u51fd\u6570\u5904\u7406\u8bf7\u6c42<\/span><br \/>\n                    <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\">\/\/ \u53d1\u9001\u54cd\u5e94<\/span><br \/>\n                    ready_socks<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">Send<\/span><span class=\"token punctuation\">(<\/span>resp<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>                <span class=\"token punctuation\">}<\/span> <span class=\"token comment\">\/\/ end if\/else<\/span><\/p>\n<p>            <span class=\"token punctuation\">}<\/span> <span class=\"token comment\">\/\/ end for ready_socks<\/span><\/p>\n<p>        <span class=\"token punctuation\">}<\/span> <span class=\"token comment\">\/\/ end for(;;)<\/span><\/p>\n<p>        <span class=\"token keyword\">return<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">private<\/span><span class=\"token operator\">:<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string ip_<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">uint16_t<\/span> port_<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u6211\u4eec\u8fd9\u91cc\u53ea\u662f\u6559\u5b66\u7528&#xff0c;\u5728\u751f\u4ea7\u4e2d\u5e38\u89c1\u7ec4\u5408\u662f \u201c\u591a\u8def\u590d\u7528 &#043; \u975e\u963b\u585e fd\u201d&#xff0c;\u907f\u514d\u5355\u8fde\u63a5\u963b\u585e\u4e8b\u4ef6\u5faa\u73af&#xff1b;select \u65f6\u4ee3\u4e5f\u5e38\u8fd9\u4e48\u505a\u3002<\/p>\n<p>\u5b57\u5178\u670d\u52a1\u5668\u7684\u4e1a\u52a1\u903b\u8f91&#xff08;main \u51fd\u6570&#xff09;&#xff1a;<\/p>\n<p><span class=\"token comment\">\/\/ dict_server.cc<\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;iostream&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unordered_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;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\">&#034;tcp_select_server.hpp&#034;<\/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> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token comment\">\/\/ \u5b57\u5178\u6570\u636e<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>unordered_map<span class=\"token operator\">&lt;<\/span>std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token punctuation\">,<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<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;cat&#034;<\/span><span class=\"token punctuation\">,<\/span>     <span class=\"token string\">&#034;\u732b&#034;<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><span class=\"token string\">&#034;dog&#034;<\/span><span class=\"token punctuation\">,<\/span>     <span class=\"token string\">&#034;\u72d7&#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;banana&#034;<\/span><span class=\"token punctuation\">,<\/span>  <span class=\"token string\">&#034;\u9999\u8549&#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;server&#034;<\/span><span class=\"token punctuation\">,<\/span>  <span class=\"token string\">&#034;\u670d\u52a1\u5668&#034;<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><span class=\"token string\">&#034;network&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;\u7f51\u7edc&#034;<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token punctuation\">{<\/span><span class=\"token string\">&#034;epoll&#034;<\/span><span class=\"token punctuation\">,<\/span>   <span class=\"token string\">&#034;\u9ad8\u6027\u80fd IO \u591a\u8def\u8f6c\u63a5\u673a\u5236&#034;<\/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 comment\">\/\/ \u4e1a\u52a1\u5904\u7406\u51fd\u6570<\/span><br \/>\n    <span class=\"token keyword\">auto<\/span> 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><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> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">*<\/span> resp<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u53bb\u6389\u672b\u5c3e\u7684\u6362\u884c\u7b26<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span>string word <span class=\"token operator\">&#061;<\/span> req<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>word<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> word<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;\\\\n&#039;<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            word<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 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>word<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>it <span class=\"token operator\">!&#061;<\/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> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token operator\">*<\/span>resp <span class=\"token operator\">&#061;<\/span> word <span class=\"token operator\">&#043;<\/span> <span class=\"token string\">&#034; -&gt; &#034;<\/span> <span class=\"token operator\">&#043;<\/span> it<span class=\"token operator\">-&gt;<\/span>second <span class=\"token operator\">&#043;<\/span> <span class=\"token string\">&#034;\\\\n&#034;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token operator\">*<\/span>resp <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;\u672a\u627e\u5230\u5355\u8bcd: &#034;<\/span> <span class=\"token operator\">&#043;<\/span> word <span class=\"token operator\">&#043;<\/span> <span class=\"token string\">&#034;\\\\n&#034;<\/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><span class=\"token string\">&#034;[Handler] \u8bf7\u6c42: %s, \u54cd\u5e94: %s&#034;<\/span><span class=\"token punctuation\">,<\/span> word<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> resp<span class=\"token operator\">-&gt;<\/span><span class=\"token function\">c_str<\/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><span class=\"token punctuation\">;<\/span><\/p>\n<p>    TcpSelectServer <span class=\"token function\">server<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;0.0.0.0&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">8080<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    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 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<p>\u5ba2\u6237\u7aef&#xff08;\u4f7f\u7528 telnet \u6216\u7b80\u5355\u5ba2\u6237\u7aef\u6d4b\u8bd5&#xff09;&#xff1a;<\/p>\n<p><span class=\"token comment\"># \u6d4b\u8bd5\u65b9\u5f0f\u4e00&#xff1a;\u7528 telnet<\/span><br \/>\ntelnet <span class=\"token number\">127.0<\/span>.0.1 <span class=\"token number\">8080<\/span><br \/>\n<span class=\"token comment\"># \u8f93\u5165 hello&#xff0c;\u56de\u8f66<\/span><\/p>\n<p><span class=\"token comment\"># \u6d4b\u8bd5\u65b9\u5f0f\u4e8c&#xff1a;\u7528 nc<\/span><br \/>\n<span class=\"token function\">nc<\/span> <span class=\"token number\">127.0<\/span>.0.1 <span class=\"token number\">8080<\/span><br \/>\nhello<br \/>\n<span class=\"token function\">cat<\/span><br \/>\nepoll<\/p>\n<hr \/>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">7.4 \u670d\u52a1\u5668\u5de5\u4f5c\u6d41\u7a0b\u56fe<\/font><\/h4>\n<p>                TcpSelectServer \u5de5\u4f5c\u6d41\u7a0b<\/p>\n<p>\u542f\u52a8<br \/>\n  <span class=\"token operator\">|<\/span><br \/>\n  <span class=\"token function\">v<\/span><br \/>\n\u521b\u5efa listen_sock \u2192 \u52a0\u5165 Selector<br \/>\n  <span class=\"token operator\">|<\/span><br \/>\n  <span class=\"token function\">v<\/span><br \/>\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510<br \/>\n\u2502         \u4e8b\u4ef6\u5faa\u73af for<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">)<\/span>         \u2502<br \/>\n\u2502                                 \u2502<br \/>\n\u2502  selector.Wait<span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>ready_socks<span class=\"token punctuation\">)<\/span>    \u2502<br \/>\n\u2502      <span class=\"token punctuation\">(<\/span>\u963b\u585e\u7b49\u5f85&#xff0c;\u76f4\u5230\u6709 fd \u5c31\u7eea<span class=\"token punctuation\">)<\/span>  \u2502<br \/>\n\u2502             \u2193 \u5c31\u7eea\u4e86            \u2502<br \/>\n\u2502  \u904d\u5386 ready_socks&#xff1a;             \u2502<br \/>\n\u2502                                 \u2502<br \/>\n\u2502  \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510    \u2502<br \/>\n\u2502  \u2502  \u662f listen_sock&#xff1f;       \u2502    \u2502<br \/>\n\u2502  \u2502  \u2192 accept \u65b0\u8fde\u63a5        \u2502    \u2502<br \/>\n\u2502  \u2502  \u2192 selector.Add<span class=\"token punctuation\">(<\/span>\u65b0 fd<span class=\"token punctuation\">)<\/span>  \u2502    \u2502<br \/>\n\u2502  \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518    \u2502<br \/>\n\u2502                                 \u2502<br \/>\n\u2502  \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510    \u2502<br \/>\n\u2502  \u2502  \u662f\u666e\u901a sock&#xff1f;           \u2502    \u2502<br \/>\n\u2502  \u2502  \u2192 Recv \u8bfb\u53d6\u8bf7\u6c42         \u2502    \u2502<br \/>\n\u2502  \u2502  \u2192 handler \u5904\u7406\u4e1a\u52a1      \u2502    \u2502<br \/>\n\u2502  \u2502  \u2192 Send \u53d1\u9001\u54cd\u5e94         \u2502    \u2502<br \/>\n\u2502  \u2502  \u82e5\u5ba2\u6237\u7aef\u65ad\u5f00&#xff1a;          \u2502    \u2502<br \/>\n\u2502  \u2502  \u2192 selector.Del<span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">)<\/span>     \u2502    \u2502<br \/>\n\u2502  \u2502  \u2192 close<span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">)<\/span>            \u2502    \u2502<br \/>\n\u2502  \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518    \u2502<br \/>\n\u2502                                 \u2502<br \/>\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500 \u56de\u5230 Wait \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518<\/p>\n<hr \/>\n<h3><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u516b\u3001select \u4f7f\u7528\u7684\u6ce8\u610f\u4e8b\u9879\u4e0e\u5e38\u89c1\u9519\u8bef<\/font><\/h3>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">8.1 \u5bb9\u6613\u72af\u7684\u9519\u8bef\u6e05\u5355<\/font><\/h4>\n<p>\u9519\u8bef 1&#xff1a;\u5fd8\u8bb0\u6bcf\u6b21\u5faa\u73af\u91cd\u5efa fd_set<\/p>\n<p><span class=\"token comment\">\/\/ \u274c \u9519\u8bef&#xff1a;\u53ea\u5728\u5faa\u73af\u5916\u521d\u59cb\u5316\u4e00\u6b21<\/span><br \/>\nfd_set read_fds<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>fd1<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>fd2<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">for<\/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\">select<\/span><span class=\"token punctuation\">(<\/span>max_fd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">,<\/span> <span class=\"token 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><br \/>\n    <span class=\"token comment\">\/\/ \u7b2c\u4e8c\u6b21\u5faa\u73af\u65f6&#xff0c;read_fds \u5df2\u7ecf\u88ab select \u4fee\u6539\u4e86&#xff01;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token comment\">\/\/ \u2705 \u6b63\u786e&#xff1a;\u6bcf\u6b21\u5faa\u73af\u91cd\u5efa&#xff08;\u6216\u7528\u526f\u672c&#xff09;<\/span><br \/>\nfd_set template_fds<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u4fdd\u5b58\u5b8c\u6574\u96c6\u5408<\/span><br \/>\n<span class=\"token function\">FD_ZERO<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>template_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>fd1<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>template_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>fd2<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>template_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    fd_set read_fds <span class=\"token operator\">&#061;<\/span> template_fds<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u6bcf\u6b21\u7528\u526f\u672c&#xff01;<\/span><br \/>\n    <span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span>max_fd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">,<\/span> <span class=\"token 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><br \/>\n    <span class=\"token comment\">\/\/ \u5904\u7406\u4e8b\u4ef6&#8230;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<hr \/>\n<p>\u9519\u8bef 2&#xff1a;nfds \u4f20\u9519<\/p>\n<p><span class=\"token comment\">\/\/ \u274c \u9519\u8bef&#xff1a;\u4f20\u7684\u662f fd \u6570\u91cf&#xff0c;\u4e0d\u662f max_fd &#043; 1<\/span><br \/>\n<span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">3<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">,<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u5982\u679c fd \u662f 3\u30015\u30017&#xff0c;\u5c31\u6f0f\u6389\u4e86 5 \u548c 7&#xff01;<\/span><\/p>\n<p><span class=\"token comment\">\/\/ \u2705 \u6b63\u786e&#xff1a;\u6700\u5927 fd \u503c &#043; 1<\/span><br \/>\n<span class=\"token function\">select<\/span><span class=\"token punctuation\">(<\/span>max_fd <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">,<\/span> <span class=\"token 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<p>\u9519\u8bef 3&#xff1a;\u6ca1\u6709\u5904\u7406 accept \u540e\u628a\u65b0 fd \u52a0\u5165 select<\/p>\n<p><span class=\"token comment\">\/\/ \u274c \u9519\u8bef&#xff1a;\u65b0\u8fde\u63a5\u6ca1\u6709\u88ab\u76d1\u63a7<\/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>listen_fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> new_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">accept<\/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><br \/>\n    <span class=\"token comment\">\/\/ \u5fd8\u4e86\u628a new_fd \u52a0\u5165 select \u76d1\u63a7&#xff01;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token comment\">\/\/ \u2705 \u6b63\u786e<\/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>listen_fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>read_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> new_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">accept<\/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><br \/>\n    <span class=\"token function\">FD_SET<\/span><span class=\"token punctuation\">(<\/span>new_fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>template_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ \u52a0\u5165\u76d1\u63a7<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>new_fd <span class=\"token operator\">&gt;<\/span> max_fd<span class=\"token punctuation\">)<\/span> max_fd <span class=\"token operator\">&#061;<\/span> new_fd<span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ \u66f4\u65b0 max_fd<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<hr \/>\n<p>\u9519\u8bef 4&#xff1a;\u5ba2\u6237\u7aef\u65ad\u5f00\u540e\u6ca1\u6709\u4ece\u96c6\u5408\u4e2d\u5220\u9664<\/p>\n<p><span class=\"token comment\">\/\/ \u274c \u9519\u8bef&#xff1a;\u65ad\u5f00\u7684 fd \u6ca1\u6709\u6e05\u7406<\/span><br \/>\nssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> buf<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 keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&lt;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token comment\">\/\/ \u6ca1\u6709\u4ece fd_set \u4e2d\u5220\u9664&#xff01;\u4e0b\u6b21 select \u8fd8\u4f1a\u76d1\u63a7\u8fd9\u4e2a\u5df2\u5173\u95ed\u7684 fd<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token comment\">\/\/ \u2705 \u6b63\u786e<\/span><br \/>\nssize_t n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">recv<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> buf<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 keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&lt;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token function\">FD_CLR<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>template_fds<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u4ece\u76d1\u63a7\u96c6\u5408\u5220\u9664<\/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>                   <span class=\"token comment\">\/\/ \u5173\u95ed fd<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<hr \/>\n<h3><font face=\"\u6977\u4f53\" color=\"#984229\" size=\"5\">\u4e5d\u3001\u603b\u7ed3\u4e0e\u5c55\u671b<\/font><\/h3>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">9.1 \u6838\u5fc3\u8981\u70b9<\/font><\/h4>\n<table>\n<tr>#\u8981\u70b9\u5173\u952e\u7ec6\u8282<\/tr>\n<tbody>\n<tr>\n<td>1<\/td>\n<td>fd_set \u662f\u4f4d\u56fe<\/td>\n<td>\u6bcf\u4e2a bit \u5bf9\u5e94\u4e00\u4e2a fd&#xff0c;FD_SET\/CLR\/ISSET \u64cd\u4f5c\u4f4d\u56fe<\/td>\n<\/tr>\n<tr>\n<td>2<\/td>\n<td>select \u4e24\u4e2a\u89d2\u8272<\/td>\n<td>\u8f93\u5165&#xff1a;\u544a\u8bc9\u5185\u6838\u76d1\u63a7\u54ea\u4e9b fd&#xff1b;\u8f93\u51fa&#xff1a;\u544a\u8bc9\u4f60\u54ea\u4e9b fd \u5c31\u7eea<\/td>\n<\/tr>\n<tr>\n<td>3<\/td>\n<td>\u5fc5\u987b\u7528\u526f\u672c<\/td>\n<td>select \u4f1a\u4fee\u6539\u4f20\u5165\u7684 fd_set&#xff0c;\u5fc5\u987b\u5148\u62f7\u8d1d\u518d\u4f20\u5165<\/td>\n<\/tr>\n<tr>\n<td>4<\/td>\n<td>nfds &#061; max_fd &#043; 1<\/td>\n<td>\u5185\u6838\u904d\u5386\u8303\u56f4\u662f [0, nfds)&#xff0c;\u4e0d\u80fd\u641e\u9519<\/td>\n<\/tr>\n<tr>\n<td>5<\/td>\n<td>\u56db\u5927\u7f3a\u70b9<\/td>\n<td>\u6570\u91cf\u9650\u5236\u3001\u6bcf\u6b21\u62f7\u8d1d\u3001\u904d\u5386 O(n)\u3001\u624b\u52a8\u91cd\u5efa\u96c6\u5408<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">9.2 \u5bb9\u6613\u6df7\u6dc6\u7684\u70b9<\/font><\/h4>\n<table>\n<tr>\u6df7\u6dc6\u70b9\u6b63\u786e\u7406\u89e3<\/tr>\n<tbody>\n<tr>\n<td>select \u8fd4\u56de\u503c\u542b\u4e49<\/td>\n<td>\u8fd4\u56de\u7684\u662f\u5c31\u7eea fd \u7684\u4e2a\u6570&#xff0c;\u4e0d\u662f\u5c31\u7eea fd \u7684\u7f16\u53f7<\/td>\n<\/tr>\n<tr>\n<td>FD_ISSET \u7684\u65f6\u673a<\/td>\n<td>\u53ea\u6709 select \u8fd4\u56de\u540e\u624d\u6709\u610f\u4e49<\/td>\n<\/tr>\n<tr>\n<td>fd_set \u4fee\u6539<\/td>\n<td>select \u4fee\u6539\u7684\u662f\u4f20\u8fdb\u53bb\u7684\u90a3\u4efd&#xff0c;\u539f\u59cb\u4fdd\u5b58\u7684\u4e0d\u53d7\u5f71\u54cd<\/td>\n<\/tr>\n<tr>\n<td>nfds \u610f\u4e49<\/td>\n<td>\u4e0d\u662f\u76d1\u63a7 fd \u7684\u6570\u91cf&#xff0c;\u662f\u6700\u5927 fd \u503c &#043; 1<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h4><font face=\"\u6977\u4f53\" size=\"4\" color=\"#112299\">9.3 select vs poll vs epoll \u5feb\u901f\u5bf9\u6bd4&#xff08;\u5b8c\u6574\u7248\u7559\u540e\u9762\u8bb2&#xff09;<\/font><\/h4>\n<p>select&#xff1a;\u4f4d\u56fe&#xff0c;\u6709\u6570\u91cf\u9650\u5236&#xff0c;\u6bcf\u6b21\u5168\u91cf\u62f7\u8d1d&#xff0c;O<span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span> \u904d\u5386<br \/>\n  \u2193 \u6539\u8fdb&#xff1a;\u53bb\u6389\u6570\u91cf\u9650\u5236&#xff0c;\u7528 pollfd \u7ed3\u6784<br \/>\npoll&#xff1a;pollfd \u6570\u7ec4&#xff0c;\u65e0\u6570\u91cf\u9650\u5236&#xff0c;\u6bcf\u6b21\u5168\u91cf\u62f7\u8d1d&#xff0c;O<span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span> \u904d\u5386<br \/>\n  \u2193 \u6539\u8fdb&#xff1a;\u5185\u6838\u7ef4\u62a4\u96c6\u5408&#xff0c;\u56de\u8c03\u673a\u5236&#xff0c;O<span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> \u83b7\u53d6\u5c31\u7eea fd<br \/>\nepoll&#xff1a;\u7ea2\u9ed1\u6811&#043;\u5c31\u7eea\u961f\u5217&#xff0c;\u65e0\u6570\u91cf\u9650\u5236&#xff0c;\u589e\u91cf\u6ce8\u518c&#xff0c;O<span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> \u83b7\u53d6<\/p>\n<hr \/>\n<p>&#x1f4ac; \u603b\u7ed3&#xff1a;\u8fd9\u7bc7\u6587\u7ae0\u6211\u4eec\u628a select \u4ece\u91cc\u5230\u5916\u62c6\u4e86\u4e00\u904d\u3002\u6838\u5fc3\u662f\u7406\u89e3 fd_set \u7684\u4f4d\u56fe\u672c\u8d28&#xff0c;\u4ee5\u53ca select \u4f5c\u4e3a&#034;\u8f93\u5165\u8f93\u51fa\u578b\u53c2\u6570&#034;\u7684\u53cc\u91cd\u8eab\u4efd\u3002\u5b57\u5178\u670d\u52a1\u5668\u7684\u5b8c\u6574\u5b9e\u73b0\u8ba9\u4f60\u770b\u6e05\u4e86 select \u670d\u52a1\u5668\u7684\u5de5\u4f5c\u6a21\u5f0f&#xff1a;\u7ef4\u62a4\u4e00\u4e2a fd \u96c6\u5408 &#043; \u4e8b\u4ef6\u5faa\u73af &#043; \u5206\u7c7b\u5904\u7406\u5c31\u7eea fd\u3002select \u7684\u56db\u4e2a\u7f3a\u70b9&#xff08;\u6570\u91cf\u9650\u5236\u3001\u5168\u91cf\u62f7\u8d1d\u3001\u904d\u5386 O(n)\u3001\u624b\u52a8\u91cd\u5efa&#xff09;\u662f poll \u548c epoll \u7684\u6539\u8fdb\u65b9\u5411\u3002\u4e0b\u4e00\u7bc7&#xff0c;\u6211\u4eec\u5148\u8bb2 poll\u2014\u2014\u5b83\u89e3\u51b3\u4e86 select \u7684\u6570\u91cf\u9650\u5236&#xff0c;\u8bbe\u8ba1\u4e5f\u66f4\u5408\u7406&#xff0c;\u4f46\u672c\u8d28\u95ee\u9898\u4ecd\u5728\u3002<\/p>\n<p>&#x1f44d; \u70b9\u8d5e\u3001\u6536\u85cf\u4e0e\u5206\u4eab&#xff1a;select \u7684\u539f\u7406\u3001\u7f3a\u9677\u548c\u4f7f\u7528\u65b9\u5f0f\u662f\u7f51\u7edc\u7f16\u7a0b\u9762\u8bd5\u5fc5\u8003\u70b9\u3002\u5982\u679c\u8fd9\u7bc7\u8bb2\u6e05\u695a\u4e86&#xff0c;\u6536\u85cf\u5907\u7528&#xff01;\u4e0b\u4e00\u7bc7 epoll \u4f1a\u66f4\u7cbe\u5f69 &#x1f4aa;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u6587\u7ae0\u76ee\u5f55select \u591a\u8def\u8f6c\u63a5\u6df1\u5ea6\u5256\u6790&#xff1a;\u4ece\u4f4d\u56fe\u539f\u7406\u5230\u5b57\u5178\u670d\u52a1\u5668\u5b9e\u73b0\u4e00\u3001select \u662f\u4ec0\u4e48&#xff1a;\u4e00\u4e2a\\&#8221;\u73ed\u4e3b\u4efb\\&#8221;\u7684\u6545\u4e8b1.1 \u95ee\u9898\u5f15\u5165&#xff1a;\u4e3a\u4ec0\u4e48\u9700\u8981 select&#xff1f;1.2 \u73ed\u4e3b\u4efb\u7c7b\u6bd4\u4e8c\u3001select \u51fd\u6570\u8be6\u89e32.1 \u51fd\u6570\u539f\u578b2.2 \u53c2\u6570\u8be6\u89e3\u53c2\u6570\u4e00&#xff1a;nfds\u53c2\u6570\u4e8c\/\u4e09\/\u56db&#xff1a;readfds\u3001writefds\u3001exceptfds\u53c2\u6570\u4e94&#xff1a;timeout2.3 \u8fd4\u56de\u503c\u4e09\u3001fd_set&amp;#xff1a<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[8195,8198,8199,55,58,43,44],"topic":[],"class_list":["post-76312","post","type-post","status-publish","format-standard","hentry","category-server","tag-io","tag-select","tag-8199","tag-c","tag-linux","tag-43","tag-44"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v20.3 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>\u3010Linux\u3011select \u591a\u8def\u8f6c\u63a5\u6df1\u5ea6\u5256\u6790\uff1a\u4ece\u4f4d\u56fe\u539f\u7406\u5230\u5b57\u5178\u670d\u52a1\u5668\u5b9e\u73b0 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" 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\u53c2\u6570\u8be6\u89e3\u53c2\u6570\u4e00&#xff1a;nfds\u53c2\u6570\u4e8c\/\u4e09\/\u56db&#xff1a;readfds\u3001writefds\u3001exceptfds\u53c2\u6570\u4e94&#xff1a;timeout2.3 \u8fd4\u56de\u503c\u4e09\u3001fd_set&amp;#xff1a\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.wsisp.com\/helps\/76312.html\" \/>\n<meta property=\"og:site_name\" content=\"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"article:published_time\" content=\"2026-02-21T23:25:30+00:00\" \/>\n<meta name=\"author\" content=\"admin\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"\u4f5c\u8005\" \/>\n\t<meta name=\"twitter:data1\" content=\"admin\" \/>\n\t<meta name=\"twitter:label2\" content=\"\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4\" \/>\n\t<meta name=\"twitter:data2\" content=\"12 \u5206\" \/>\n<script type=\"application\/ld+json\" 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