python退出无限循环与KeyboardInterrupt异常

Question

My while loop does not exit when Ctrl+C is pressed. It seemingly ignores my KeyboardInterrupt exception. The loop portion looks like this:

while True:
  try:
    if subprocess_cnt <= max_subprocess:
      try:
        notifier.process_events()
        if notifier.check_events():
          notifier.read_events()
      except KeyboardInterrupt:
        notifier.stop()
        break
    else:
      pass
  except (KeyboardInterrupt, SystemExit):
    print '\nkeyboardinterrupt found!'
    print '\n...Program Stopped Manually!'
    raise

Again, I'm not sure what the problem is but my terminal never even prints the two print alerts I have in my exception. Can someone help me figure this problem out?

Answer 1

Replace your break statement with a raise statement, like below:

while True:
  try:
    if subprocess_cnt <= max_subprocess:
      try:
        notifier.process_events()
        if notifier.check_events():
          notifier.read_events()
      except KeyboardInterrupt:
        notifier.stop()
        print 'KeyboardInterrupt caught'
        raise  # the exception is re-raised to be caught by the outer try block
    else:
      pass
  except (KeyboardInterrupt, SystemExit):
    print '\nkeyboardinterrupt caught (again)'
    print '\n...Program Stopped Manually!'
    raise

The two print statements in the except blocks should execute with '(again)' appearing second.