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

static void *thread_loop (void *unused)
{
  sigset_t block_set, pending_set;

  sigemptyset (&block_set);
  sigaddset (&block_set, SIGUSR2);
  if (pthread_sigmask (SIG_BLOCK, &block_set, NULL) != 0)
    {
      printf ("failed to set the list of blocked signals\n");
    }

  while (1)
    {
      sigpending (&pending_set);

      printf ("pending_set = %08X\n", pending_set);

      if (sigismember (&pending_set, SIGUSR2) != 0)
	break;

      sleep (1);
    }

  printf ("exiting thread_loop()\n");

  return NULL;
}

int main (int argc, char **argv)
{
  int rv;
  pthread_t thr_id;

  rv = pthread_create (&thr_id, NULL, thread_loop, NULL);
  if (rv != 0)
    {
      printf ("failed to create thread.\n");
      exit (1);
    }

  /* give the second thread a chance to run */
  sleep (5);

  while (1)
    {
      if (pthread_kill (thr_id, SIGUSR2) != 0)
        break;
    }

  exit (0);
}