服务器比较简陋，为了学习poll的使用，只向客户端回写一条html语句。启动服务器后，浏览器发起请求，服务端向浏览器写回html，响应字符串，然后可以看到，浏览器解析并显示 Hello Poll！.
启动服务端：
用浏览器访问：
浏览器解析出字符串：
完整代码：
?1 #include <stdio.h> ???2 #include <stdlib.h> ???3 #include <unistd.h> ???4 #include <netinet/in.h> ???5 #include <arpa/inet.h> ???6 #include <unistd.h> ???7 #include <string.h> ????8 #include <poll.h> ???9 #include <sys/socket.h> ??10 #include <sys/types.h> ??11 #include <sys/stat.h> ??12 ???13 ???14 #define POLLFD_SIZE 1024 /* struct pollfd 结构体数组最大上限 */ ??15 ???16 ???17 ???18 /* 关心描述符集事件数组*/ ??19 struct pollfd array_pollfd[POLLFD_SIZE]; ??20 ???21 /* 结构体成员详情 ?22 struct pollfd ??23 { ?24 ????int fd; ???????// 关心的描述符 ?25 ????short events; ?// 关心的事件 ?26 ????short revents; // 发生的事件 ?27 }; ?28 */ ??29 ???30 /* 获取一个监听连接的sockfd */ ??31 int run_getsockfd(const char*ip, int port); ??32 ???33 /* 执行poll检测 */ ??34 void run_poll(int listen_sockfd); ??35 ???36 /* 响应客户端的连接，并添加新的描述符到关心事件中 */ ??37 void run_accept(int listen_sock); ??38 ???39 /* 当与客户端连接的描述符有事件就绪时，做出响应 */ ??40 void run_action( int index); ??41 ???42 int main(int argc, char **argv) ??43 { ??44 ????if(argc != 3) ??45 ????{ ??46 ????????printf("usage: [server_ip] [server_port]"); ??47 ????????return 1; ??48 ????} ??49 ???50 ????int listen_sockfd = run_getsockfd(argv[1], atoi(argv[2])); ??51 ???52 ????run_poll(listen_sockfd); ??53 ???54 ????return 0; ??55 } ??56 ???57 ???58 /* 调用poll 并检测返回事件 */ ??59 void run_poll(int listen_sockfd) ??60 { ??61 ????/* 将负责监听连接的sockfd注册事件 */ ??62 ????array_pollfd[0].fd = listen_sockfd; ??63 ????array_pollfd[0].events = POLLIN; ??64 ???65 ????/* 初始化数组中的描述符 */ ??66 ????int idx_init = 1; ??67 ????for(; idx_init < POLLFD_SIZE; ++idx_init) ??68 ????{ ??69 ????????array_pollfd[idx_init].fd = -1; ??70 ????} ??71 ????int timeout = 1000; /* 设定一秒后超时 */ ??72 ???73 ???74 ????while(1) ??75 ????{ ??76 ????????int ret_poll = poll(array_pollfd, ?POLLFD_SIZE, timeout); ??77 ???78 ????????if(ret_poll == 0) ???????/* 超时 ???*/ ??79 ????????????printf("timeout\n"); ??80 ????????else if(ret_poll < 0) ???/* 执行出错*/ ??81 ????????????perror("poll()"); ??82 ????????else ??83 ????????{/* 有关心的事件就绪 ?*/ ??84 ???85 ????????????/* 遍历数组，轮询检测poll的结果 ?*/ ??86 ????????????int idx_check = 0; ??87 ????????????for(idx_check = 0; idx_check < POLLFD_SIZE; ++idx_check) ??88 ????????????{ ??89 ????????????????if(idx_check == 0 && array_pollfd[0].revents & POLLIN) ??90 ????????????????{/* listen_sockfd 读事件就绪 */ ??91 ????????????????????run_accept(listen_sockfd); ???92 ????????????????} ??93 ????????????????else if(idx_check != 0) ??94 ????????????????{/* 与客户端连接的sockfd 有事件就绪 */ ??95 ????????????????????run_action(idx_check); ??96 ????????????????} ??97 ????????????} ??98 ????????} ??99 ????} // end while 1 ?100 } ?101 ??102 ??103 /* 当与客户端连接的描述符有事件就绪时，做出响应 */ ?104 void run_action( int index) ?105 { ?106 ????if(array_pollfd[index].revents & POLLIN) ?107 ????{/* 客户端读事件发生 */ ?108 ????????char buf[1024]; ?????????/* 存储从客户端读来的消息 */ ??109 ????????memset(buf, 0, sizeof(buf)); ?110 ????????ssize_t s = read(array_pollfd[index].fd, buf, sizeof(buf)-1); ?111 ????????if(s > 0) ?112 ????????{ ?113 ????????????buf[s-1] = ‘\0‘; ?114 ????????????printf("client say$ %s \n", buf); ?115 ????????????array_pollfd[index].events = POLLOUT; ?116 ????????} ?117 ????????else if( s <= 0) ?118 ????????{ ?119 ????????????printf("client quit!\n"); ?120 ????????????close(array_pollfd[index].fd); ?121 ????????????array_pollfd[index].fd = -1; ?122 ????????} ?123 ??124 ????} ?125 ????else if (array_pollfd[index].revents & POLLOUT) ?126 ????{/* 客户端写事件发生 */ ?127 ????????/* 使用浏览器测试，写回到客户端，浏览器会解析字符串，显示 Hellp Epoll! */ ?128 ????????const char* msg = "HTTP/1.1 200 OK\r\n\r\n<html><br/><h1>Hello poll!</h1></html>"; ?129 ????????write(array_pollfd[index].fd, msg, strlen(msg)); ?????130 ????????close(array_pollfd[index].fd); ?131 ????????array_pollfd[index].fd = -1; ?132 ????} ?133 } ?134 ??135 ??136 /* 响应客户端的连接，并添加新的描述符到关心事件中 */ ?137 void run_accept(int listen_sock) ?138 { ?139 ????struct sockaddr_in cliaddr; ?140 ????socklen_t clilen = sizeof(cliaddr); ?141 ??142 ????int new_sock = accept(listen_sock, (struct sockaddr*)&cliaddr, &clilen); ?143 ????if( new_sock < 0) ?144 ????{ ?145 ????????perror("accept"); ?146 ????????return ; ?147 ????} ?148 ??149 ????printf("与客户端连接成功: ip %s port %d \n", inet_ntoa(cliaddr.sin_addr), ntohs(cliaddr.sin_port)); ?150 ????/* 将新socket描述符添加到数组中 */ ?151 ????int idx_find = 1; ?152 ????for(; idx_find < POLLFD_SIZE; ++idx_find) ?153 ????{ ?154 ????????if(array_pollfd[idx_find].fd < 0) ?155 ????????{ ?156 ????????????array_pollfd[idx_find].fd = new_sock; ?157 ????????????array_pollfd[idx_find].events = POLLIN ; ?158 ????????????break; ?159 ????????} ?160 ????} ????161 ????if(idx_find == POLLFD_SIZE) ?162 ????{ ?163 ????????perror("连接超出最大限度，add array_pollfd[]"); ?164 ????????return; ?165 ????} ?166 ??167 } ?168 ??169 /* 获取一个监听socket */ ?170 int run_getsockfd(const char* ip, int port) ?171 { ?172 ????int sock = socket(AF_INET, SOCK_STREAM, 0); ?173 ????if( sock < 0){ ?174 ????????perror("socket()"); ?175 ????????exit(1); ?176 ????} ?177 ??178 ????int opt = 1; ?179 ????setsockopt(sock , SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)); ?180 ??181 ????struct sockaddr_in server; ?182 ????bzero(&server, sizeof(server)); ?183 ????server.sin_addr.s_addr = inet_addr(ip); ?184 ????server.sin_port = htons(port); ?185 ????server.sin_family = AF_INET; ?186 ??187 ????if(bind(sock, (struct sockaddr *)&server, sizeof(server) ) < 0){ ?188 ????????perror("bind()"); ?189 ????????exit(2); ?190 ????} ?191 ??192 ????if(listen(sock, 5) < 0){ ?193 ????????perror("listen()"); ?194 ????????exit(3); ?195 ????} ?196 ??197 ????return sock; ?198 } ?【Linux网络编程】基于TCP流 I/O多路转接(poll) 的高性能http服务器
原文地址：https://www.cnblogs.com/jiangzhaowei/p/8831108.html