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Date: Wed, 22 Apr 2009 12:34:32 +0200
From: Roman Pisl <rpisl@domain.hid>
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Subject: Re: [Xenomai-help] Problem with mutexes in daemon
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To: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
Cc: xenomai@xenomai.org

Gilles Chanteperdrix napsal(a):
> Roman Pisl wrote:
>> Hello,
>> I'm experiencing weird behavior with mutexes in a daemon application. 
>> After daemon() is called, unnamed mutexes fail on call 
>> rt_mutex_release() with -EPERM. Everything is ok for named mutexes.
>>
>> Is there something special with daemon and unnamed mutexes - should all 
>> have name? Or is it a bug? I'm using kernel 2.6.28 and Xenomai 2.4.6.1.
>>
>> Example showing this problem is attached.
> 
> Unnamed mutexes are local to a process. Since forking results in a
> different process, mutexes are not preserved.
> 
> Yes, Xenomai behaviour is not intuitive, but fixing this requires
> internal changes.
> 

I understand, but daemon() is the first call and everything is done in 
the new forked process.

What is the best solution for now? Is everything except unnamed mutexes 
supposed to work well in daemon or should I cancel the concept of daemon 
at all?

Roman