linux下setitimer定时器与定时器取消

#include <stdio.h>  #include <signal.h>  #include <time.h>  #include <string.h>  #include <stdlib.h>  #include <unistd.h>  void timer_thread(union sigval v)  {    static int i = 0;    printf ("timer_thread function! %d\n", v.sival_int);    printf ("i = %d\n", ++i);}  int main()  {      timer_t timerid;      struct sigevent evp;      memset(&evp, 0, sizeof(struct sigevent));       //清零初始化      evp.sigev_value.sival_int = 111;                //也是标识定时器的，回调函数可以获得      evp.sigev_notify = SIGEV_THREAD;                //线程通知的方式，派驻新线程      evp.sigev_notify_function = timer_thread;       //线程函数地址      if (timer_create(CLOCK_REALTIME, &evp, &timerid) == -1)      {           perror("fail to timer_create");          exit(-1);      }       /* 第一次间隔it.it_value这么长,以后每次都是it.it_interval这么长,就是说it.it_value变0的时候会装载it.it_interval的值 */    struct itimerspec it;      it.it_interval.tv_sec = 2;      it.it_interval.tv_nsec = 0;      it.it_value.tv_sec = 3;      it.it_value.tv_nsec = 0;      if (timer_settime(timerid, 0, &it, NULL) == -1)      {           perror("fail to timer_settime");        exit(-1);    }    //pause();    while (1);    return 0;}/*  * int timer_gettime(timer_t timerid, struct itimerspec *curr_value);  * 获取timerid指定的定时器的值，填入curr_value  */                  

编译需加：-lrt

输出结果：

(倒计时3秒)

timer_thread function! 111
i = 1
(每2s)
timer_thread function! 111

i = 2
(每2s)
timer_thread function! 111
i = 3
(每2s)
timer_thread function! 111
i = 4



linux下取消用setitimer设置的定时器
setitimer设置it_interval和it_value为零： 

void uninit_time()  {      struct itimerval value;      value.it_value.tv_sec = 0;      value.it_value.tv_usec = 0;      value.it_interval = value.it_value;      setitimer(ITIMER_REAL, &value, NULL);  }