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Date: Wed, 8 Oct 2008 13:48:33 -0600
From: John Hein <jhein@timing.com>
To: John Baldwin <jhb@freebsd.org>
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Cc: Daniel Eischen <deischen@freebsd.org>, freebsd-threads@freebsd.org
Subject: Re: pthread_cleanup_push & pthread_cleanup_pop usage
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John Baldwin wrote at 14:09 -0400 on Oct  8, 2008:
 > Don't Do That (tm).  The spec explicitly states that they can be defined as 
 > macros and that code using it needs to put them in the same block.

Thanks for the responses.  I like deischen's response best to work
around the problem short term, but I suspect that's not very portable.
And as jhb describes using it outside the same block violates the
spirit of intended use.

Note that the example I gave (pop off the cleanup stack in a catch
block) is not our only "violation".  We also push in one function and
either never [explicitly] pop or possibly pop in another function.

So that leaves me wondering about possible techniques for cleanup on
thread cancellation or exit.  Alfred touched on one method, and I see
that pthread_key_create takes an optional destructor, so that sounds
like a possible avenue to explore.