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

void handler(int a) {}

int main() {
	signal(SIGUSR1, &handler);

	int fpid = fork();
	if (fpid == 0) {
		while (1) {
			pause();
			printf("child\n");
		}
	}
	else {
		while (1) {
			printf("parent\n");
			kill(fpid, SIGUSR1);
			sleep(1);
		}
	}
	return 0;
}