sub event_loop {
   my $next_event = &get_next_event;  # e.g. time() + 5
   if (select($rh, $wh, $eh, $next_event - time())) {
      &process($rh, $wh, $eh);
   } elsif ($next_event <= time()) {
      &do_timed_events;
   }
}

&event_loop while $running;