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Date: Mon, 10 Jan 2005 13:00:07 +0100
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: Problem in pthread_key_create
Message-ID: <20050110120007.GF7748@cygbert.vinschen.de>
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References: <200501091731 DOT j09HVm9m000706 AT thor DOT remedy DOT nl>
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On Jan  9 18:31, Johnny Willemsen wrote:
> Hi,
> 
> Posted this last Friday but didn't got anything back. I think this is a bug
> in the pthread library of Cygwin. Can someone have a look at this?
> 
> Johnny 
> 
> -----Original Message-----
> From: Johnny Willemsen [mailto:jwillemsen AT remedy DOT nl] 
> Sent: vrijdag 7 januari 2005 14:57
> To: 'cygwin AT cygwin DOT com'
> Subject: Question about pthread_key_create
> 
> Hi all,
> 
> A question, I had a look at the implementation of pthread_key_create. When
> an invalid key is passed, a EBUSY is returned. This looks very strange to
> me, isn't it better to return EINVAL just as the pthread_key_delete does?

No, that's not a bug.  Please read the SUSv3 description for
pthread_key_create() here:

http://www.opengroup.org/onlinepubs/009695399/functions/pthread_key_create.html

Please note especially the chapter

  RATIONALE/Non-Idempotent Data Key Creation.

It should sufficiently describe why returning EBUSY in this case isn't
such a bad idea.  Unfortunately, the SUSv3 definition left the actual
behaviour open to the implementation.  Another implementation could also
reset the data key to NULL in subsequent calls to pthread_key_create().
Either way, the bottom line is, don't call pthread_key_create() more
than once for the same data key.


Corinna

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

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