linux poll demo

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/poll.h>

int main() {
    struct pollfd fds[2];
    int timeout = 5000; // 5秒超时

    // 初始化文件描述符
    fds[0].fd = STDIN_FILENO;
    fds[0].events = POLLIN;
    fds[1].fd = open("test.txt", O_RDONLY);
    if (fds[1].fd == -1) {
        perror("open");
        return 1;
    }
    fds[1].events = POLLIN;

    while (1) {
        int ret = poll(fds, 2, timeout);
        if (ret == -1) {
            perror("poll");
            break;
        } else if (ret == 0) {
            printf("Timeout occurred!\n");
            continue;
        }

        for (int i = 0; i < 2; i++) {
            if (fds[i].revents & POLLIN) {
                char buffer[1024];
                ssize_t len = read(fds[i].fd, buffer, sizeof(buffer));
                if (len > 0) {
                    buffer[len] = '\0';
                    printf("Read from fd %d: %s", fds[i].fd, buffer);
                }
            }
        }
    }

    close(fds[1].fd);
    return 0;
}