#include <sys/types.h>
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>

static int alarm_fired = 0;

//comment3
void ding(int sig)
{
    alarm_fired = 1;
}

//comment1
int main()
{
    pid_t pid;
    printf("alarm application starting\n");

    pid = fork();
    switch (pid) {
        case -1:
            perror("fork failed");
            exit(1);
        case 0:
            sleep(5);
            kill(getppid(), SIGALRM);
            exit(0);
    }

    //comment2
    printf("waiting for alarm to go off\n");
    (void) signal(SIGALRM, ding);

    pause();
    if (alarm_fired)
        printf("Ding!\n");

    printf("done.\n");
    exit(0);
}