itimer-stop.c

#include <sys/time.h>
#include <err.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

static void
sigalrm_handler(int sig __unused)
{
	static const char msg[] = "SIGALRM\n";

	write(STDOUT_FILENO, msg, sizeof(msg) - 1);
}

int
main(void)
{
	struct sigaction sa;
	struct itimerval it;
	int error;

	memset(&sa, 0, sizeof(sa));
	sa.sa_handler = sigalrm_handler;
	error = sigaction(SIGALRM, &sa, NULL);
	if (error != 0)
		err(1, "sigaction");
	
	memset(&it, 0, sizeof(it));
	it.it_value.tv_sec = 1;
	it.it_interval.tv_sec = 1;
	error = setitimer(ITIMER_REAL, &it, NULL);
	if (error != 0)
		err(1, "setitimer");

	while (true)
		pause();
}