Simple thread-safe counter?

[Rob Williscroft]

Tim Peters wrote in news:mailman.1223.1112417955.1799.python-
list at python.org in comp.lang.python:

> [Paul Rubin]
>> I'd like to have a function (or other callable object) that returns
>> 0, 1, 2, etc. on repeated calls.  That is:
>>
>>    print f()   # prints 0
>>    print f()   # prints 1
>>    print f()   # prints 2
>>    # etc.
>>
>> There should never be any possibility of any number getting returned
>> twice, or getting skipped over, even if f is being called from
>> multiple threads.
>> 
>> What's the simplest and most natural way to do this?  I can think of a
>> few but am not sure that they work.  And I can think of some ways that
>> are sure to work, but are messier than I'd like.
> 
> The GIL is your friend here:
> 

Yes but IIUC the GIL is only CPython, will this work with Jython,
IornPython etc ? (*)

>     import itertools
>     f = itertools.count().next
> 

*) I'm either being rhetorical or stupid, not sure which :).

Rob.
-- 
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