alarm报警 Linux

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/timerfd.h>
#include <inttypes.h>

void handle_alarm(int fd) {
    uint64_t expirations;
    read(fd, &expirations, sizeof(expirations));
    printf("Alarm triggered! Expired %lu times.\n", expirations);
}

int main() {
    int timer_fd = timerfd_create(CLOCK_REALTIME, 0);
    if (timer_fd == -1) {
        perror("timerfd_create");
        exit(EXIT_FAILURE);
    }

    struct itimerspec new_value;
    new_value.it_value.tv_sec = 5;  // 初始延迟5秒
    new_value.it_value.tv_nsec = 0;
    new_value.it_interval.tv_sec = 5;  // 每隔5秒触发一次
    new_value.it_interval.tv_nsec = 0;

    if (timerfd_settime(timer_fd, 0, &new_value, NULL) == -1) {
        perror("timerfd_settime");
        close(timer_fd);
        exit(EXIT_FAILURE);
    }

    while (1) {
        handle_alarm(timer_fd);
        sleep(1);  // 简单循环等待
    }

    close(timer_fd);
    return 0;
}