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Date:	Wed, 12 Jul 2006 11:46:27 +0200
From:	Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To:	cygwin AT cygwin DOT com
Subject:	Re: Pthread.h issue
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On Jul 12 10:39, Mark Hadfield wrote:
> #if defined (PTHREAD_PRIO_INHERIT)
>   pthread_mutexattr_getprotocol(m_attr, &protocol);
>   POUT3(caller, protocol, PTHREAD_PRIO_INHERIT, PTHREAD_PRIO_PROTECT, 
> PTHREAD_PRIO_NONE);
> #endif
> 
> This expands to valid C code if and only if the macros 
> PTHREAD_PRIO_INHERIT, PTHREAD_PRIO_PROTECT and PTHREAD_PRIO_NONE are 
> defined to integer constants. But the definitions are empty 
> (/usr/sys/sinclude/pthread.h, lines 63-65):
> 
> #define PTHREAD_PRIO_INHERIT
> #define PTHREAD_PRIO_NONE
> #define PTHREAD_PRIO_PROTECT
> [...]
> So, why would Cygwin pthread have empty definitions for these macros? Is 
> it safe to override the definitions? Would it be safer to omit the code 
> that uses them on this platform?

This looks like a leftover.  Mutex priorities are not supported
by Windows and nobody ever implemented it in Cygwin, so the corresponding
functions pthread_mutexattr_getprotocol and pthread_mutexattr_setprotocol
return with ENOSYS.  The above preprocessor test should better check for
_POSIX_THREAD_PRIO_INHERIT, which is the macro indicating that the
corresponding functionality is supported.

I will remove the above defines for the next Cygwin version. 

This implies that we would be glad if somebody would implement thread
priority inheritance in Cygwin.  http://cygwin.com/acronyms/#PTC


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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