linux c 应用编程定时器函数

在 Linux C 应用编程中，对于多线程编程中的定时器函数使用，通常可以借助 pthread 库和系统提供的定时器相关的函数来实现。

首先，常见的定时器函数有 setitimer() 和 alarm() 。setitimer() 函数可以更精确地设置定时器，它可以设置为 ITIMER_REAL（以实时时间递减）、ITIMER_VIRTUAL（以进程在用户态执行的时间递减）和 ITIMER_PROF（以进程在用户态和内核态执行的时间递减）三种模式。

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include <signal.h>
#include <time.h>#define TIMER_INTERVAL_SEC 2void timer_handler(union sigval sv)
{printf("Timer expired. Thread ID: %ld\n", pthread_self());
}void* thread_function(void* arg)
{timer_t timer_id;struct sigevent sev;sev.sigev_notify = SIGEV_THREAD;sev.sigev_notify_function = timer_handler;sev.sigev_value.sival_ptr = &timer_id;timer_create(CLOCK_REALTIME, &sev, &timer_id);struct itimerspec its;its.it_interval.tv_sec = TIMER_INTERVAL_SEC;its.it_interval.tv_nsec = 0;its.it_value.tv_sec = 1;its.it_value.tv_nsec = 0;timer_settime(timer_id, 0, &its, NULL);while (1) {sleep(1);}timer_delete(timer_id);pthread_exit(NULL);
}int main()
{pthread_t thread_id1, thread_id2;pthread_create(&thread_id1, NULL, thread_function, NULL);pthread_create(&thread_id2, NULL, thread_function, NULL);pthread_join(thread_id1, NULL);pthread_join(thread_id2, NULL);return 0;
}

#include <stdio.h>
#include <time.h>
#include <signal.h>
#include <unistd.h>
#include <stdlib.h>#define TIMER_SIG SIGRTMINvoid timer_handler(int sig, siginfo_t *si, void *uc) {// 定时器到期时被调用的处理函数printf("Timer fired!\n");
}int main() {timer_t timerid;struct sigevent sev;struct itimerspec its;struct sigaction sa;// 设置处理函数sa.sa_flags = SA_SIGINFO;sa.sa_sigaction = timer_handler;sigemptyset(&sa.sa_mask);if (sigaction(TIMER_SIG, &sa, NULL) == -1) {perror("sigaction");exit(1);}// 创建定时器sev.sigev_notify = SIGEV_SIGNAL;sev.sigev_signo = TIMER_SIG;sev.sigev_value.sival_ptr = &timerid;if (timer_create(CLOCK_REALTIME, &sev, &timerid) == -1) {perror("timer_create");exit(1);}// 启动定时器its.it_value.tv_sec = 2; // 初次到期时间，2秒后its.it_value.tv_nsec = 0;its.it_interval.tv_sec = 1; // 定时器周期，每隔1秒its.it_interval.tv_nsec = 0;if (timer_settime(timerid, 0, &its, NULL) == -1) {perror("timer_settime");exit(1);}sleep(10); // 等待定时器触发几次return 0;
}