infinite loop with signal chaining

HI

I'm trying to play around with some signals. When I try to catch the FPE signal and chain it with another I get a infinite loop of them being called repeatedly. I'm not sure why. I'm also not sure why I cant see my alarm.

Any advice?

Thanks

Code:

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

/*
 * Old handlers
 */
void (*old_sigfpe_handler)(int);
void (*old_sigint_handler)(int);
int sigint_count = 0;

/*
 * New handlers
 */
void another_sigfpe_handler(int sig) {
	fprintf(stderr, "I got the signal first!\n");
	old_sigfpe_handler(sig);
}

void handler(int sig) {
	void *retval;
	
	switch(sig) {
		case SIGINT:
			if(sigint_count < 1) {
				fprintf(stderr, "You pressed Control-C\n ");
				fprintf(stderr, "I wont end until you press");
				fprintf(stderr, "it 3 times\n");
			} else {
				retval = signal(SIGINT, old_sigint_handler);
				if(retval == SIG_ERR)
					perror("Error setting SIGINT handler");
			}
			
			++sigint_count;
			break;
		case SIGFPE:
			fprintf(stderr, "Don't divide by zero.\n");
			alarm(5);

			break;
		case SIGUSR1:
			fprintf(stderr, "Somebody signalled me!\n");
			break;
		case SIGALRM:
			fprintf(stderr, "You divided by zero 5 seconds ago\n");
			break;
		case SIGSEGV:
			fprintf(stderr, "You can't dereference null pointer\n");
			exit(1);
	}
}


/*
 * Program
 */
int main() {
	void *old_handler;
	int retval;
	int a, b;
	
	/* Install new sig handlers */
	old_sigint_handler = signal(SIGINT, handler);
	if(old_sigint_handler == SIG_ERR) {
		perror("Error setting new SIGINT handler");
		return 1;
	}
	
	old_handler = signal(SIGFPE, handler);
	if(old_sigfpe_handler == SIG_ERR) {
		perror("Error setting first new SIGFPE handler");
		return 1;
	}
	
	old_handler = signal(SIGUSR1, handler);
	if(old_handler == SIG_ERR) {
		perror("Error setting new SIGUSR1 handler");
		return 1;
	}
	
	old_handler = signal(SIGALRM, handler);
	if(old_handler == SIG_ERR) {
		perror("Error setting new SIGALRM handler");
		return 1;
	}
	
	old_handler = signal(SIGSEGV, handler);
	if(old_handler == SIG_ERR) {
		perror("Error setting new SIGSEGV handler");
		return 1;
	}
	
	old_sigfpe_handler = signal(SIGFPE, another_sigfpe_handler);
	if(old_sigfpe_handler == SIG_ERR) {
		perror("Error setting second new SIGFPE handler");
		return 1;
	}
	
	/* Main user loop */
	fprintf(stderr, "Read to go\n\n");
	while(42) {
		retval = scanf("%i %i", &a, &b);
		if(retval < 2) {
			fprintf(stderr, "return value = %i\n", retval);
		} else {
			if(a == 1 && b == 1)
				retval = *((int *)0);
			else 
				fprintf(stderr, "q = %i\n", a/b);
		}
	}

	/* Profit! */
	return 0;
}

Well I know one thing I did wrong now, cant recover after a FPE so should of ended the program there.

Doesnt explain the looping though