DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 184433861038
Subject: Re: PTHREAD_MUTEX_SHARED on Cygwin
To: cygwin@cygwin.com
References: <657c8576-2715-8c80-a59a-23453306230f@netcologne.de>
Message-ID: <082bd13d-da7d-6fa0-1b0d-f9c721424615@gmail.com>
Date: Sat, 9 Jan 2021 21:24:42 +0100
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From: Marco Atzeri via Cygwin <cygwin@cygwin.com>
Reply-To: Marco Atzeri <marco.atzeri@gmail.com>
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On 09.01.2021 19:23, Thomas Koenig via Cygwin wrote:
> 
> Hi,
> 
> there is a branch of gfortran for implementing coarrays based on a
> shared memory implementation instead of MPI, the devel_coarray/native
> branch.
> 
> I tried it out on Cygwin, but it doesn't work there (hangs on the
> first sync).
> 
> The branch uses pthread mutexes and condition variables
> with PTHREAD_PROCESS_SHARED for synchronization between processes.
> 
> I also ran the attached test program, which gave the output
> 
> pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED)failed: No 
> error
> 
> 
> Is it correct that PTHREAD_PROCESS_SHARED is not supported on
> Cygwin?  Is it supported for condition variables, or is the fact
> that it is reported as working an oversight?
> 
> If PTHREAD_PROCESS_SHARED does not work, are there known workarounds?
> 
> Best regards
> 
>      Thomas
> 

some time ago I worked on a similar shared memory issue on Fortran

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47030

but I was never able to fully follow-up
and it seems my patch was incomplete, and caused

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89079

so it is possible that this issue is also impacting
your problem.

Regards
Marco

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