#include <err.h>
#include <errno.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static void
on_sigint(int signo)
{
	char buf[1024];

	snprintf(buf, sizeof(buf), "signal %d\n", signo);
	(void)write(STDOUT_FILENO, buf, strlen(buf));
}

static void *
thr(void *cookie)
{
	sigset_t sigs;

	if (sigemptyset(&sigs) == -1)
		err(EXIT_FAILURE, "sigemptyset");
	if (sigaddset(&sigs, SIGINT) == -1)
		err(EXIT_FAILURE, "sigaddset(SIGINT)");
	if (pthread_sigmask(SIG_BLOCK, &sigs, NULL) == -1)
		err(EXIT_FAILURE, "pthread_sigmask");
	sleep(10);
	return NULL;
}

int
main(void)
{
	struct sigaction sa;
	pthread_t t;
	int error;

	memset(&sa, 0, sizeof(sa));
	sa.sa_handler = &on_sigint;
	if (sigfillset(&sa.sa_mask) == -1)
		err(EXIT_FAILURE, "sigfillset");
	if (sigaction(SIGINT, &sa, NULL) == -1)
		err(EXIT_FAILURE, "sigaction(SIGINT)");

	error = pthread_create(&t, NULL, &thr, NULL);
	if (error) {
		errno = error;
		err(EXIT_FAILURE, "pthread_create");
	}
	printf("join\n");
	fflush(stdout);
	error = pthread_join(t, NULL);
	if (error) {
		errno = error;
		err(EXIT_FAILURE, "pthread_join");
	}
	fflush(stdout);
	return ferror(stdout);
}