[Python-ideas] Atomic counter / atomic increment

[M.-A. Lemburg]

On 25.08.2016 20:10, Ben Hoyt wrote:
>> As long as Python uses a GIL to protect C level function
>> calls, you can use an iterator for this:
>>
>> import itertools
>> x = itertools.count()
>> ...
>> mycount = next(x)
>>
> 
> Yeah, that's a neat hack -- I saw it recommended on StackOverflow, and saw
> it used in the standard library somewhere. I think that's probably okay in
> the *CPython* stdlib, because it's CPython so you know it has the GIL. But
> this wouldn't work in other Python implementations, would it (IronPython
> and Jython don't have a GIL). Or when itertools.count() is implemented in
> pure Python on some system? Seems like it could blow up in someone's face
> when they're least expecting it. I also think using *iter*tools is a pretty
> non-obvious way to get a thread-safe counter.

All true.

Having an implementation in threading which hides away the
details would be nice. On CPython using iterators would
certainly be one of the most efficient ways of doing this.

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Marc-Andre Lemburg
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