simple sigalrm sample

timer.c

/* Andre Augusto Giannotti Scota (https://sites.google.com/view/a2gs/  andre.scota@gmail.com) */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>

void handleAlarmSignal(int signum)
{
	printf("Timeout!\n");
	exit(1);
}

int main(int argc, char *argv[])
{
	char cmd[100] = {0};
	unsigned int left = 0;

	if(argc != 3){
		printf("Usage: %s <TIMER> <TIMEOUT>\n", argv[0]);
		return(0);
	}

	signal(SIGALRM, handleAlarmSignal);

	sprintf(cmd, "sleep %s", argv[1]);

	alarm(atoi(argv[2]));

	system(cmd); // using system() to spaw another process (alarm() and sleep() doesnt work well together)

	left = alarm(0);

	printf("Normal exit (%u seconds left).\n", left);

	return(0);
}