Prgm 10(Real time clock)

#include<stdio.h>
#include<unsistd.h>
#include<signal.h>
#define INTERVALS

void callone(int signo)
{
   alarm(INTERVALS);
   printf("In calling\n");
}

int main()
{
   struct sigaction action;
   sig emptyset | &action,sa_mask;
   sigaction.sa_handler=((void(*)0)callme);
   sigaction.sa_flags=SA_RESTART;
   if(sigaction(SIGALARM,&action,0)==-1)
     {
        printf("Alarm error\n");
        return(1);
     }
     
   if(alarm(INTERVAL)==-1)
     {
        printf("Alarm error\n");
        exit(0);
     }
     
   else
     {
        sleep(10);
        printf("Alarm executed\n");
     }
}