[Python-Dev] Issue #10348: concurrent.futures doesn't work on BSD

["Martin v. Löwis"]

Am 30.12.2010 16:40, schrieb Antoine Pitrou:
> On Thu, 30 Dec 2010 16:04:16 +0100
> Łukasz Langa <lukasz at langa.pl> wrote:
>>
>> Some answers Philip gave already. Knowing all these things would let us decide whether switching the module off on systems that don't meet the requirements is okay and can we get away with just documenting how to make it work.
> 
> I really don't think it is our job to maintain a list of OS/versions
> which work and don't work.

Of course not. I would propose a dynamic test: check how many POSIX
semaphores the installation supports, and fail if it's less than
200 (say).

>> ISTM concurrent.futures was included a bit too early in the distribution.
>> The module has problems not only on BSD [1].
> 
> I'm not sure concurrent.futures is the culprit, rather than
> multiprocessing itself (or perhaps even some core Python functionality).
> Actually, the threading-based part of concurrent.futures probably works
> fine.

Well, "the culprit" really is FreeBSD. However, concurrent.futures
apparently makes freehanded use of semaphores, in a way that the
FreeBSD authors didn't expect them to be used (if they expected them
to be used at all, that is).

Regards,
Martin