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Re: Cygwin port of Guile 2.2
From: |
Andy Wingo |
Subject: |
Re: Cygwin port of Guile 2.2 |
Date: |
Wed, 03 May 2017 11:24:30 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) |
On Wed 03 May 2017 05:18, Derek Upham <address@hidden> writes:
> Andy Wingo <address@hidden> writes:
>
>> On Mon 01 May 2017 22:48, Derek Upham <address@hidden> writes:
>>
>>> Running pthread_join() on a thread only guarantees that the thread has
>>> returned an exit value.
>>
>> Would you mind providing a reference please? It is not that I don't
>> believe you but I think it's important to know whether this is a bug in
>> Guile or in the pthreads implementation.
>
> It’s not explicit, but it’s heavily implied by the pthread_exit(3) man
> page:
A specific implementation's man page is interesting but not the
specification. The specification is "The Open Group Base Specifications
Issue 7 IEEE Std 1003.1-2008, 2016 Edition" and can be found here:
http://pubs.opengroup.org/onlinepubs/9699919799/
Note that pthread_exit() is not the normal way for a Guile thread to
exit. I thought we removed uses of this but I see that there are a
couple more that need to be removed. Are you using it? It's certainly
not one that we suggest. We don't use pthread_cleanup_push either --
the lifetime of the thread from Guile's POV isn't limited to a dynamic
extent of scm_with_guile, as the thread could be created by the user, as
https://lists.gnu.org/archive/html/guile-devel/2011-04/msg00133.html
Anyway, I digress. After looking at the specification of pthread_join
(http://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_join.html),
things do not seem clear to me. Does the thread "terminate" before or
after the pthread_key destructors run? Given that:
* pthread_key destructors must run in the thread AFAIU; to be able to
call pthread_setspecific in a destructor you need a fresh
or from a fresh new thread, and spawning a new thread to run cleanup
seems unlikely
* pthread_key destructors can call any function
I think there's an argument that a thread doesn't "terminate" until its
thread-local key destructors have finished running, and therefore
pthread_join doesn't return until after the key destructors have run.
This is my understanding of what happens from reading NPTL. Do I
understand correctly that you are on Cygwin? Could it be a cygwin
pthreads incompatibility?
Andy
- Re: Cygwin port of Guile 2.2, Derek Upham, 2017/05/01
- Re: Cygwin port of Guile 2.2, Andy Wingo, 2017/05/02
- Re: Cygwin port of Guile 2.2, Derek Upham, 2017/05/02
- Re: Cygwin port of Guile 2.2,
Andy Wingo <=
- Re: Cygwin port of Guile 2.2, szgyg, 2017/05/03
- Re: Cygwin port of Guile 2.2, Derek Upham, 2017/05/03
- Re: Cygwin port of Guile 2.2, Andy Wingo, 2017/05/09
- Re: Cygwin port of Guile 2.2, Derek Upham, 2017/05/12
- Re: Cygwin port of Guile 2.2, Andy Wingo, 2017/05/15
- Re: Cygwin port of Guile 2.2, zv, 2017/05/04