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Date: Mon, 13 Oct 2008 15:18:09 +0200
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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Subject: Re: [Xenomai-help] pthread_[set|get]specific()
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To: Wolfgang Grandegger <wg@domain.hid>
Cc: xenomai-help <xenomai@xenomai.org>

Wolfgang Grandegger wrote:
> Gilles Chanteperdrix wrote:
>> Wolfgang Grandegger wrote:
>>> Hello,
>>>
>>> can pthread_[set|get]specifi()c be used safely in user space real-time
>>> tasks. Or does it result in a switch to secondary mode?
>> I would expect pthread_getspecific to be safe on all platforms though
>> (and actually, I think the fast mutexes implementation relies on that).
>>
>> I would say it should be always safe or always non-safe. So, you may run
>> a test with T_WARNSW (or XNTRAPSW) and you will know whether the
>> implementation on your platform is safe.
>>
>> pthread_setspecific is another story, maybe it can trigger a re-allocation?
> 
> In fact, I only need pthread_getspecific in the real-time context. Hm,
> is it really fast? Maybe scanning my private phtread ids is faster.

Yes it is supposed to be a pointer dereferencement, faster than a hash
or list lookup.

-- 
                                                 Gilles.