[Python-ideas] An error in multiprocessing on MacOSX?

Antoine Pitrou solipsis at pitrou.net
Wed Nov 21 20:25:26 CET 2012


On Wed, 21 Nov 2012 16:12:04 +0100
Sturla Molden <sturla at molden.no> wrote:

> See this:
> 
> http://mail.scipy.org/pipermail/numpy-discussion/2012-August/063593.html
> 
> According to Apple enineers:
> 
> """
> For API outside of POSIX, including GCD and technologies like
> Accelerate, we do not support usage on both sides of a fork(). For
> this reason among others, use of fork() without exec is discouraged in
> general in processes that use layers above POSIX.
> """
> 
> Multiprocessing on OSX calls os.fork, but not os.exec.
> 
> Thus, is multiprocessing errorneously implemented on Mac? Forking 
> without calling exec means that only APIs inside POSIX can be used by 
> the child process.

Or perhaps "fork()" is erroneously implemented on Mac.
Regardless, http://bugs.python.org/issue8713 has a proposal by Richard
to make things more configurable on all POSIX platforms.

Regards

Antoine.





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