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

void
ouch (int sig)
{
  sigset_t set, oset;
  sigemptyset (&set);
  sigprocmask (SIG_SETMASK, &set, &oset);
  sigprocmask (SIG_SETMASK, NULL, &set);
  printf ("sig %d, set 0%x, oset 0%x\n", sig, set, oset);
}

int
main (int argc, char **argv)
{
  sigset_t set, oset;
  sigemptyset (&set);
  sigaddset (&set, SIGUSR1);
  sigaddset (&set, SIGINT);
  sigprocmask (SIG_SETMASK, &set, &oset);
  printf ("set 0%x, oset 0%x\n", set, oset);
  signal (SIGALRM, ouch);
  alarm (1);
  pause ();
  sigprocmask (SIG_SETMASK, NULL, &oset);
  printf ("oset 0%x\n", oset);
  exit (0);
}