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From: Florian Weimer <fw@deneb.enyo.de>
To: enh <enh@google.com>
Cc: "Michael Kerrisk \(man-pages\)" <mtk.manpages@gmail.com>,
	linux-man@vger.kernel.org
Subject: Re: [PATCH] pthread_kill.3: Update to match POSIX.
Date: Wed, 13 Nov 2019 07:10:40 +0100	[thread overview]
Message-ID: <87mud09uhr.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <CAJgzZopvMb8KGyA5b6afWG83hw-cZgOdvOdPYb28iS+f5wDkmw@mail.gmail.com> (enh's message of "Tue, 12 Nov 2019 21:59:25 -0800")

* enh:

> On Tue, Nov 12, 2019 at 9:51 PM Florian Weimer <fw@deneb.enyo.de> wrote:
>>
>> * enh:
>>
>> > no, because the C library has two choices when a thread exits:
>> >
>> > 1. unmap the thread.
>> >
>> > 2. keep the thread around for recycling.
>> >
>> > if you choose 1 (optimizing for space, like Android), your dereference
>> > is illegal.
>>
>> This choice is only available for threads in a detached state.  For
>> joinable threads, a conforming implementation cannot immediately
>> deallocate all data structures on thread termination.  Among other
>> things, it has to store the future return value of pthread_join
>> somewhere.
>
> ah, you're trying to say "signal 0 is potentially usable for a
> joinable thread that's waiting to be joined"? that's true, but i'm not
> sure how that's relevant to this patch. that wouldn't be an "invalid
> thread ID" until it's joined.

Correct.  That's POSIX's argument why ESRCH wouldn't be valid to
return here.  It's still a forceful loss of information, and
particularly annoying since POSIX doesn't specify pthread_tryjoin.

But I'm glad we've brought our discussion to a conclusion. 8-)

  reply	other threads:[~2019-11-13  6:10 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-12 20:36 [PATCH] pthread_kill.3: Update to match POSIX enh
2019-11-12 21:38 ` Florian Weimer
2019-11-12 21:40   ` enh
2019-11-12 21:52     ` Florian Weimer
2019-11-12 22:06       ` enh
2019-11-12 22:11         ` Florian Weimer
2019-11-12 22:22           ` enh
2019-11-12 22:28             ` Florian Weimer
2019-11-13  5:27               ` enh
2019-11-13  5:51                 ` Florian Weimer
2019-11-13  5:59                   ` enh
2019-11-13  6:10                     ` Florian Weimer [this message]
2021-11-09 23:00                       ` enh
2021-11-10  7:14                         ` Florian Weimer
2021-11-12  0:01                           ` enh
2021-11-12 13:02                             ` Florian Weimer

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