alarm.c

非常简单的定时器代码

/*  file: timer.c
    function: show POSIX interval timer and signal handling
    compile: gcc -o timer timer.c -lrt
    run:  ./timer
 */

#include <unistd.h>
#include <sys/types.h>
#include <stdio.h>
#include<stdlib.h>
#include <linux/limits.h>
#include <time.h>
#include <signal.h>
#include "abstime.h"

int counter, counter_tmp;/* counter value*/
timer_t timer_id;
struct itimerspec time_out,abstime;  /* time_out settings*/
struct timespec start, stop; /* start and stop time for the counter*/
int hour,min,sec;
struct tm *tptime;
time_t timep;
timer_data data;
int alarmflag=0;

void timer_handler( int signo);
void time_drift ( void );
int main(){
        sigset_t  mask;
        struct sigaction sig_act;
        struct sigevent  evp;
        int status;
        /*timer_data data;
        data.type = -1;  */
        counter=10;
        counter_tmp=counter;

        /* create a relative timer*/


        sig_act.sa_handler =  timer_handler;
        sig_act.sa_flags = 0;
        sigemptyset(&sig_act.sa_mask);
        sigaction(SIGUSR1, & sig_act, NULL);

        sig_alr.sa_handler = myhandler;
	    sig_alr.sa_flags = 0;
	    sigemptyset(&sig_alr.sa_mask);
	    sigaction(SIGALRM, &sig_alr, NULL);

        evp.sigev_signo = SIGUSR1;
        evp.sigev_notify = SIGEV_SIGNAL;
        status = timer_create(CLOCK_REALTIME, &evp, &timer_id);
        if (status == -1){
            fprintf(stderr, "Error in timer_create\n");
            exit(1);
            }
        printf("Enter the alarm time in this way\n hour:minuit:second:");
        scanf("%d:%d:%d",&hour,&min,&sec);
      time_out.it_value.tv_sec=1;
      time_out.it_value.tv_nsec=0;

       /* record start time*/
      clock_gettime( CLOCK_REALTIME, & start);

      abstm.it_value.tv_sec=start.tv_sec+time_out.it_value.tv_sec;
      abstm.it_value.tv_nsec=start.tv_nsec+time_out.it_value.tv_nsec;
      data.tvalue.it_value.tv_nsec += start.tv_nsec;
      data.tvalue.it_value.tv_sec += start.tv_sec;
      if (data.tvalue.it_value.tv_nsec >= BILLION) {
         data.tvalue.it_value.tv_nsec -= BILLION;
         data.tvalue.it_value.tv_sec++;
      }
      data.flags = TIMER_ABSTIME;
      /* set timers */
      status = timer_settime(timer_id, TIMER_ABSTIME, &abstm, NULL);
      if (status == -1)
          {
           fprintf(stderr, "fail to set timer\n");
           exit(1);
          }

   for(;;)   pause();
}
void timer_handler( int signo )
{

     time(&timep);
     p=localtime(&timep);

     if((p->tm_hour==hour) && (p->tm_min==min) && (p->tm_sec==sec))

     {
      alarm(10);
      alarmflag=1;
      printf("alarm on\n");
      }
      if(alarmflag==1)
         printf("%d:%d:%d  alarm time\n",p->tm_hour, p->tm_min, p->tm_sec);
      if(alarmflag==0)
         printf("%d:%d:%d\n",p->tm_hour, p->tm_min, p->tm_sec);


      abstm.it_value.tv_sec+=time_out.it_value.tv_sec;
      abstm.it_value.tv_nsec+=time_out.it_value.tv_nsec;
      timer_settime(timer_id, TIMER_ABSTIME, &abstm, NULL);



}
static void myhandler()
{
    alarmflag=0;
    printf("alarm off\n");

}