timer_signal_demo.c

#include <signal.h>
#include <time.h>
#include <stdio.h>
#include <signal.h>

void sh(int sig)
{
    for (double f = 0; f < 10; f += 0.5) {
        printf("    f = %g\n", f);
        usleep(100000);
    }
}

void main()
{
    struct sigaction sa;
    sigemptyset(&sa.sa_mask);
    sa.sa_handler = &sh;
    sa.sa_flags = 0;
    int c = sigaction(SIGALRM, &sa, NULL);
    printf("c = %d\n", c);

    timer_t tt;
    int a = timer_create(CLOCK_REALTIME, NULL, &tt);
    printf("a = %d\n", a);

    struct itimerspec it;
    it.it_interval.tv_sec = 0;
    it.it_interval.tv_nsec = 0;
    it.it_value.tv_sec = 1;
    it.it_value.tv_nsec = 0;

    int b = timer_settime(tt, 0, &it, NULL);
    printf("b = %d\n", b);

    for (int i = 0; i < 20; i++) {
        printf("  i = %d\n", i);
        usleep(100000);
    }
}

Note: Perl document says it's not okay to use sleep() and signals at the same time, because sleep() might be implemented with signals as well.