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

static sigset_t sigset;

static void signal_handler(int sig)
{
	printf("Got it!\n");
}

static void *wait_for_signal(void *whatever)
{
	signal(SIGUSR1, signal_handler);

	sleep(5);
	printf("Unblocking now.\n");
	pthread_sigmask(SIG_UNBLOCK, &sigset, NULL);

	sleep(1000);
	return NULL;
}

static void w4s_other_thread(void)
{
	pthread_t thread;
	pthread_create(&thread, NULL, wait_for_signal, NULL);
	pthread_join(thread, NULL);
}

int main(int argc, char **argv)
{
	sigemptyset(&sigset);
	sigaddset(&sigset, SIGUSR1);
	pthread_sigmask(SIG_BLOCK, &sigset, NULL);

	if(argc > 1)
		w4s_other_thread();
	else
		wait_for_signal(NULL);

	return 0;
}