/* $begin counterprob */
#include "csapp.h"

int counter = 0;

void handler(int sig) 
{
    counter++;
    printf("hand_counter=%d\n", counter); 
    sleep(1); /* do some work in the handler */
    return;
}

int main() 
{
    int i, pid, status;
    
    Signal(SIGUSR2, handler);
    pid = Fork();
    if (pid == 0) {  /* child */
	for (i = 0; i < 5; i++) {
	    Kill(getppid(), SIGUSR2);
            sleep(1);
	    printf("sent SIGUSR2 to parent\n");
	}
	exit(0);
    }

    Wait(&status);
    printf("counter=%d\n", counter); 
    exit(0);
}
/* $end counterprob */