linux 2.4 epoll

#include <sys/epoll.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>

int main() {
    int epfd = epoll_create(1); // 创建 epoll 实例
    if (epfd == -1) {
        perror("epoll_create");
        return 1;
    }

    int fd = open("test.txt", O_RDONLY);
    if (fd == -1) {
        perror("open");
        close(epfd);
        return 1;
    }

    struct epoll_event event;
    event.events = EPOLLIN; // 监听可读事件
    event.data.fd = fd;

    if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &event) == -1) {
        perror("epoll_ctl: add");
        close(fd);
        close(epfd);
        return 1;
    }

    struct epoll_event events[10];
    int nfds = epoll_wait(epfd, events, 10, -1); // 等待事件发生
    if (nfds == -1) {
        perror("epoll_wait");
        close(fd);
        close(epfd);
        return 1;
    }

    for (int i = 0; i < nfds; i++) {
        if (events[i].events & EPOLLIN) {
            printf("File descriptor %d is ready for reading.\n", events[i].data.fd);
        }
    }

    close(fd);
    close(epfd);
    return 0;
}