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

/* Simple error handling functions */

#define handle_error_en(en, msg) \
	do { errno = en; perror(msg); exit(EXIT_FAILURE); } while (0)


int main(int ac, char *av[])
{
	sigset_t set;
	int i;
	char buff[512];

	(void)puts("#start");

	sigemptyset(&set);
	sigaddset(&set, SIGRTMIN+2);
	sigaddset(&set, SIGRTMIN+3);
	i = pthread_sigmask(SIG_BLOCK, &set, NULL);
	if (i != 0)
		handle_error_en(i, "pthread_sigmask() failed");

	(void)puts("#mark1");

	/*
	 * stupid /bin/kill in Linux cannot handle realtime signal
	 * *names*, so we pass the signal number instead
	 */
	(void)snprintf(buff, sizeof(buff), "kill -s %d %ld", (int)SIGRTMIN+2, (long)getpid());
	(void)printf("# executing '%s'\n", buff);	
	(void)system(buff);

	(void)puts("#mark2");
	
	(void)sleep(2);
	(void)puts("#mark3");

	i = pthread_sigmask(SIG_UNBLOCK, &set, NULL);
	if (i != 0)
		handle_error_en(i, "pthread_sigmask() failed");

	/*
	 * unblocking the SIGRTMIN signals will trigger the default handler for
	 * the SIGRT signals, which terminates the process, so we will never reach
	 * this point in the program
	 */
	(void)puts("#notreached");

	return EXIT_SUCCESS;
}