/*********************************************************************************
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* Copyright: (C) 2025 LingYun IoT System Studio
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* All rights reserved.
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*
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* Filename: epoll.c
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* Description: This file is epoll example.
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*
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* Version: 1.0.0(11/06/2025)
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* Author: Guo Wenxue <guowenxue@gmail.com>
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* ChangeLog: 1, Release initial version on "11/06/2025 10:33:45 AM"
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*
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********************************************************************************/
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <errno.h>
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#include <sys/epoll.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#define MAX_EVENTS 2 /* 监听 STDIN + sockfd */
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int main(void)
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{
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int sockfd;
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struct sockaddr_in addr;
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int nfds;
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int reuse = 1;
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int epfd;
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struct epoll_event ev, events[MAX_EVENTS];
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sockfd = socket(AF_INET, SOCK_STREAM, 0); /* 创建套接字 */
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addr.sin_family = AF_INET;
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addr.sin_port = htons(8888);
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addr.sin_addr.s_addr = INADDR_ANY;
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setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse));
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bind(sockfd, (struct sockaddr *)&addr, sizeof(addr));
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listen(sockfd, 5);
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/* 创建 epoll 实例 */
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epfd = epoll_create1(0);
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if (epfd < 0)
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{
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printf("epoll_create1 failure: %s\n", strerror(errno));
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return 1;
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}
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/* 将 STDIN(键盘) 添加到 epoll 监控列表 */
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ev.events = EPOLLIN;
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ev.data.fd = STDIN_FILENO;
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if (epoll_ctl(epfd, EPOLL_CTL_ADD, STDIN_FILENO, &ev) < 0)
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{
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printf("epoll_ctl add stdin failure: %s\n", strerror(errno));
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return 2;
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}
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/* 将 socket 添加到 epoll 监控列表 */
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ev.events = EPOLLIN;
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ev.data.fd = sockfd;
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if (epoll_ctl(epfd, EPOLL_CTL_ADD, sockfd, &ev) < 0)
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{
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printf("epoll_ctl add sockfd failure: %s\n", strerror(errno));
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return 2;
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}
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printf("epoll() monitor socket[8888] and stdin now...\n");
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while (1)
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{
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/* 调用 epoll 等待事件发生 */
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nfds = epoll_wait(epfd, events, MAX_EVENTS, 10000);
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if (nfds == -1)
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{
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printf("epoll error: %s\n", strerror(errno));
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break;
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}
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else if (nfds == 0)
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{
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printf("timeout...\n");
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continue;
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}
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/* 程序走到这里说明nfds>0，即监听的文件描述符中有事件发生了. */
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/* 有多少个文件描述符发生了事件就处理多少个 */
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for (int i = 0; i < nfds; i++)
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{
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int fd = events[i].data.fd;
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if (fd == STDIN_FILENO)
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{
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char buf[128];
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ssize_t n = read(STDIN_FILENO, buf, sizeof(buf) - 1);
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if (n > 0)
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{
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buf[n] = '\0';
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printf("You typed in keyboard: %s\n", buf);
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}
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}
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else if (fd == sockfd)
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{
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int client = accept(sockfd, NULL, NULL);
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if (client >= 0)
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{
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printf("Accept and close connection: %d\n", client);
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close(client);
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}
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}
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}
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}
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close(sockfd);
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return 0;
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}
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