Strange threading behaviour

Rotwang sg552 at
Thu Jun 21 20:14:32 CEST 2012

On 21/06/2012 18:26, Dieter Maurer wrote:
> Rotwang<sg552 at>  writes:
>> [...]
>> Can anyone help?
> It looks as if some waiting operation
> in the "wait_window" call did not release the GIL (the "Global Interpreter
> Lock" which ensures that at most one Python thread can run at a given
> time and protects the Python data structures such as the reference counts
> and interpreter state).
> In this case, you could expect some non-deterministic behaviour.
> If your thread is fast enough to finish before the internal
> activity inside "wait_window" gets the GIL again,
> everything completes immediately; otherwise, things complete
> only after the internal waiting ends and Python code is again executed.

OK, that makes sense - it could certainly explain why the print and open 
commands worked fine but the thread got stuck at pickle.dump. Thanks.

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