From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Tue, 14 Oct 2008 15:44:20 +0200
From: Jan Kiszka <jan.kiszka@domain.hid>
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Subject: Re: [Xenomai-core] __thread instead of pthread_get/setspecific
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To: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
Cc: xenomai-core <xenomai@xenomai.org>

Gilles Chanteperdrix wrote:
> Jan Kiszka wrote:
>> Ack. There are rt_printf (rtdk) and the task-self services of vxworks,
>> vrtx and native skins. So if I get an OK for the proposal, I'll convert
>> the rest, too.
> 
> And I really do not understand how the keys can be chosen at
> compilation-time, especially in the situation where multiple libraries
> allocate __thread objects separately: how does the compiler know which
> key to give for each library ?

The keys are known at linking time when a) their context is module-local
and b) their TLS storage can be appended to main's TLS area (and that
can only happen during initial linking, of course).


BTW, another advantage of TLS over getspecific /wrt task-self is that it
overcomes its laziness: its now cheap and easy to set self in the thread
trampoline.

Philippe, could it be that vrtx's sc_tinquiry implementation is broken?
I only find the corresponding pthread_setspecific in the lib
constructor. That pattern totally disagrees with native and vxworks.

Jan

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