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Date: Mon, 21 Sep 2015 11:00:48 +0200
From: Julien Ramseier <>
Subject: Re: pthread_join stuck in infinite loop

Thanks for the explanations. I was misled by the glibc doc.


> Le 20 sept. 2015 à 20:41, Jens Gustedt <> a écrit :
> Am Sonntag, den 20.09.2015, 20:29 +0200 schrieb Szabolcs Nagy:
>> * Julien Ramseier <> [2015-09-20 20:07:28 +0200]:
>>> pthread_join() never returns when calling it on a detached thread.
>>> I would expect it to return EINVAL instead.
>> [...]
>> in particular the glibc man page says EINVAL is correctly
>> reported in all cases which i dont think is true: there
>> is a race between the detached thread exiting an join.
> Yes, in general this is simply not possible. Otherwise the system
> would have to keep track of all threads that had been started by the
> process. The idea of detaching a thread (or starting it detached) is
> that the system resources that it occupies can be freed as soon as it
> exits.
> So just don't make the assumption that you may call join in such a
> situation. The resources of the thread and the thread ID may even
> already have been attributed to a new thread that started after the
> first one has exited. So you are not even sure which thread your id is
> naming.
> Jens

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