C语言网络编程最佳实践指南

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <netdb.h>
#include <arpa/inet.h>

int main() {
    // 1. 创建一个监听套接字
    int sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd == -1) {
        perror("socket");
        exit(1);
    }

    // 2. 设置套接字为非阻塞
    int flags = fcntl(sockfd, F_GETFL, 0);
    if (flags == -1) {
        perror("fcntl");
        exit(1);
    }
    flags |= O_NONBLOCK;
    if (fcntl(sockfd, F_SETFL, flags) == -1) {
        perror("fcntl");
        exit(1);
    }

    // 3. 绑定套接字
    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(8080);
    if (bind(sockfd, (struct sockaddr *) &addr, sizeof(addr)) == -1) {
        perror("bind");
        exit(1);
    }

    // 4. 监听套接字
    if (listen(sockfd, 5) == -1) {
        perror("listen");
        exit(1);
    }

    // 5. 进入事件循环
    while (1) {
        // 监测套接字是否可读
        struct timeval timeout;
        timeout.tv_sec = 1;
        timeout.tv_usec = 0;
        fd_set fds;
        FD_ZERO(&fds);
        FD_SET(sockfd, &fds);
        int nready = select(sockfd + 1, &fds, NULL, NULL, &timeout);
        if (nready == -1) {
            perror("select");
            exit(1);
        }

        // 如果套接字可读，接受连接
        if (FD_ISSET(sockfd, &fds)) {
            struct sockaddr_in client_addr;
            socklen_t len = sizeof(client_addr);
            int newsockfd = accept(sockfd, (struct sockaddr *) &client_addr, &len);
            if (newsockfd == -1) {
                perror("accept");
            } else {
                // 处理连接...
            }
        }
    }

    // 6. 关闭套接字
    close(sockfd);
    return 0;
}