The sigwait function blocks until a signal in the specified set is received.

What if more than one of those signals received?

What if several threads are calling sigwait for the same signal(s)?

computation_state_t state;
sigset_t set;
main( ) {
  pthread_t thread;

  sigemptyset(&set);
  sigaddset(&set, SIGINT);
  sigprocmask(SIG_BLOCK,
              &set, 0);
  pthread_create(&thread, 0, monitor, 0);
  long_running_procedure( );
}

void *monitor( ) {
  int sig;
  while (1) {
    sigwait(&set, &sig);
    display(&state);
  }
  return(0);
}