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From: Alexander Monakov <amonakov@ispras.ru>
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Subject: Re: semaphore redesign
Date: Tue, 3 Mar 2015 01:40:37 +0300 (MSK)
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On Sun, 1 Mar 2015, Szabolcs Nagy wrote:
> sorry
> 
> the code is ok (applications cannot rely on the barrier in case of
> failure), it can lead to surprising results if the application
> uses relaxed atomics, but it's not a conformance issue

There was some follow up on IRC with the conclusion, as I understood, that
even though the rest of memory may be unsynchronized after returning an error,
the memory holding the semaphore itself needs to be synchronized (otherwise
the decision to return an error might have been based on stale memory).

Does sem_getvalue need to synchronize memory as well?  I think it should, but
current implementation does not.

Alexander