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

["Martin v. Löwis"]

>> If you can make the above change, the question then is what API 
>> multiprocessing semaphores should be built upon. It seems that you 
>> are saying that they should use SysV IPC, and only fall back to 
>> POSIX IPC if SysV IPC doesn't work/exist (are there any platforms 
>> where this would be the case?)
> 
> Actually, I'd probably recommend the opposite. IMO POSIX IPC is
> better designed and easier to work with so it would be my first
> choice.

"better designed and easier to work with" don't count if you have to
do both, anyway. The code will be ugly - so what, once it is written?
It's not being exposed to the user.

> SysV would be a fallback for when POSIX IPC is unavailable,
> broken, incomplete, etc.

The problem seems to be that it is not possible to reliably determine
these cases. In particular, the ridiculous low limits seem to be
difficult to detect, and it's not clear what a required minimum level
should be.

Regards,
Martin