multiprocessing and Locks
gvverdad at gmail.com
Mon Apr 13 07:08:14 CEST 2009
On Apr 13, 3:30 am, Piet van Oostrum <p... at cs.uu.nl> wrote:
> >>>>> gvv <gvver... at gmail.com> (G) wrote:
> >G> Hi All,
> >G> I am trying to understand multiprocessing, but I am getting a Runtime
> >G> error on the
> >G> code below. What am I missing or doing wrong?
> >G> Error is:
> >G> RuntimeError: Lock objects should only be shared between processes
> >G> through inheritance
> [code deleted]
> I guess you can't share locks (and probably other objects) between
> processes from a Pool. Maybe because there is no direct parent-child
> relation or so (there is a separate thread involved). There is nothing
> in the doc that explicitely forbids it AFAICT but it says that you have
> to be careful with sharing. But it could be a bug.
> You can do it with a manager, however, but this involves an additional
> process under the hood.
> if __name__ == "__main__":
> manager = multiprocessing.Manager()
> lock = manager.Lock()
> pool = multiprocessing.Pool(processes=5)
> for i in xrange(100):
> pool.apply_async(func=RunFunc, args=(i,lock))
> Piet van Oostrum <p... at cs.uu.nl>
> URL:http://pietvanoostrum.com[PGP 8DAE142BE17999C4]
> Private email: p... at vanoostrum.org
Thanks for your help. It worked.
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