timer

[superpollo]

Paul Moore wrote:
> 2009/6/29 MRAB <python at mrabarnett.plus.com>:
> 
>>superpollo wrote:
>>
>>>hi folks.
>>>
>>>the follwing shoud print 'stuff' for 3 seconds and then stop. why it does
>>>not work? (prints stuff forever)
>>>
>>>     1 #!/usr/bin/python
>>>     2
>>>     3 import threading
>>>     4 import sys
>>>     5
>>>     6 t = threading.Timer(3.0, sys.exit)
>>>     7 t.start()
>>>     8 while True:
>>>     9     print "stuff ",
>>>
>>
>>The Timer runs the function in another thread. Perhaps sys.exit is just
>>exiting that thread and not the main thread.
> 
> 
> sys.exit raises a SystemExit exception, which will get handled in the
> new thread (where it won't do anything). Conceded, this isn't
> particularly intuitive.
> 
> For a non-toy example, you'd probably create an Event object, use your
> timer to set the event, and your while loop would do while
> event.is_set(), so the problem wouldn't arise.
> 
> Paul.

so why this does not work?

       1 #!/usr/bin/python
       2
       3 import threading
       4
       5 e = threading.Event()
       6 t = threading.Timer(3.0, e.set())
       7 t.start()
       8 while not e.isSet():
       9     print "stuff ",

it does *NOT* print (but it should, shouldn't it?), then exits after 3 
sec but with error:

Exception in thread Thread-1:Traceback (most recent call last):
   File "/usr/lib/python2.3/threading.py", line 442, in __bootstrap
     self.run()
   File "/usr/lib/python2.3/threading.py", line 575, in run
     self.function(*self.args, **self.kwargs)
TypeError: 'NoneType' object is not callable

what gives?