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

void ouch(int sig) 
{
    printf("Ouch!  Got signal %d\n", sig);  // danger call printf in signal handler

    // try without the next line and kill from another window see signals.h to see what happened
    if (sig==SIGINT) signal(SIGINT, SIG_DFL);  // restore the default
}

void wakeup(int sig)
{
    printf("Wake up!!\n");
    printf("zzzzzzzzzzzzzzzz\n");
}

int main()
{
    printf("PID: %d\n", getpid());

    signal(SIGHUP, ouch);     // 1
    signal(SIGINT, ouch);     // 2
    signal(SIGQUIT, ouch);    // 3
    signal(SIGABRT, ouch);    // 6
    signal(SIGKILL, ouch);    // 9
    signal(SIGALRM, wakeup);  // 14

//    signal(SIGINT, SIG_IGN);  // ignore the alarm forever
    for (int i=0; i<100; i++) {
        printf("tick - ");
        fflush(stdout);
        sleep(1);
        printf("tock\n");
        fflush(stdout);
        sleep(1);
    }

    return 0;
}