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Threading a lengthy C function

Robin Becker robin at jessikat.fsnet.co.uk
Thu Nov 20 13:18:49 EST 2003 
.
.....
>If the original posters intent is simply to call functions in a dll, he
>should probably try out ctypes - ctypes handles the GIL automatically
>(release before calling the function, acquire it back after return of
>the function, and even grabbing the GIL if a callback into Python is
>done).  And it avoids SWIG completely.
>
>Thomas
I'm not sure I understand how the last part is done unless all callback
functions are known to ctypes and even then I'm not sure how ctypes
would know how to associate a particular call back event with the owner
thread. Are ctypes callbacks somehow defined uniquely for each callout?

The other thing I never quite get is what part of the C api I'm allowed
to use without having the GIL I think it safest to assume I may not call
any python api without having it.

Wrapping completely independent DLLs seems reasonable, but how does
ctypes know that a particular extension/dll actually assumes that it has
the GIL at entry which is mostly what extensions need.
-- 
Robin Becker
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