#include <pthread.h>
#include <stdio.h>

pthread_mutex_t mutex;
void *thr_routine(void *arg)
{
	printf("trying to lock mutex...\n");
	if (pthread_mutex_lock(&mutex)) {
		printf("error lock mutex\n");
		abort();
	}
	printf("mutex locked\n");
	if (pthread_mutex_unlock(&mutex))
		printf("error unlock mutex\n");
	return (0);
}

void handler(int sig, siginfo_t *info, void *ucp)
{
	static int i = 1;
	printf("received signal(%d): %d\n", i++, sig);
}

int main()
{
	struct sigaction sa;
	pthread_attr_t attr;
	pthread_t td;
	sigset_t mask;
	int i;

	pthread_mutex_init(&mutex, NULL);
	pthread_attr_init(&attr);
	//pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM);
	pthread_mutex_lock(&mutex);
	sigemptyset(&sa.sa_mask);
	sa.sa_flags = SA_SIGINFO;
	sa.sa_sigaction = handler;
	sigaction(SIGUSR1, &sa, NULL);
	pthread_create(&td, &attr, thr_routine, NULL);
	sigfillset(&mask);
	pthread_sigmask(SIG_SETMASK, &mask, NULL);
	for (i = 0; i < 3; ++i) {
		sleep(1);
		printf("send signal SIGUSR1\n");
		kill(getpid(), SIGUSR1);
	}
	pthread_mutex_unlock(&mutex);
	pthread_join(td, NULL);	
	return (0);
}