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Re: snap-2004-11-03 breakage
- From: Alexander Terekhov <TEREKHOV at de dot ibm dot com>
- To: Ross Johnson <rpj at ise dot canberra dot edu dot au>
- Cc: pthreads-win32 <pthreads-win32 at sources dot redhat dot com>
- Date: Wed, 3 Nov 2004 17:32:24 +0100
- Subject: Re: snap-2004-11-03 breakage
> But how does ec_thread_getpid() portably determine if the thread
> exists or not?
Define "exists" first. If you mean "tryjoin", see
> Every function that takes a thread ID argument has the same problem
> as pthread_kill() if pointers are used.
Yes, but it's an application bug.
Sent by: email@example.com
To: pthreads-win32 <firstname.lastname@example.org>
Subject: Re: snap-2004-11-03 breakage
Alexander Terekhov wrote:
>>Code like (from Ettercap)
>> pthread_t pid = ec_thread_getpid("golem");
>> if (pid != 0)
>Code it like
> pthread_t tid;
> if (ec_thread_getpid("golem",&tid)
But how does ec_thread_getpid() portably determine if the thread
exists or not?
>Don't rely on idiotic pthread_kill() "testing". The standard
>doesn't preclude the use of pointers for thread IDs (e.g.
>inside pthread_t structure).
Oops. I should have recognised that because ...
>Pointers become indeterminate and
>trigger undefined behavior for any nonassignment access once
>the reference storage gets freed. Conforming implementations
>are allowed to reclaim/free that referenced storage when
>detached thread is terminated or joinable thread is terminated
>and joined. Use of "retired" pthread_t values (e.g. as
>pthread_kill() argument) after that moment will trigger
... that's exactly why pthread_t was changed in pthreads-win32.
Every function that takes a thread ID argument has the same problem
as pthread_kill() if pointers are used.