static volatile bool sleep_noSleep;

svoid sleep(long ms) {
  ping();
  if (ms < 0) ret;
  // allow spin locks
  if (isAWTThread() && ms > 100) fail("Should not sleep on AWT thread");
  try {
    Thread.sleep(ms);
  } catch (Exception e) { throw new RuntimeException(e); }
}

svoid sleep() ctex {
  if (sleep_noSleep) fail("nosleep");
  print("Sleeping.");
  sleepQuietly();
}