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Date: Wed, 18 Nov 2009 21:11:05 +0100
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: Problem with fcnlt F_GETLK command
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On Nov 18 08:08, jmsplat101-cygwin AT yahoo DOT co DOT uk wrote:
> Hello,
> 
> I've down loaded version 1.7 onto my Windows XP laptop (uname -a
> reports CYGWIN_NT-5.1 XXXXXXXXXX 1.7.0(0.217/5/3) 2009-11-10 13:03
> i686 Cygwin) and I'm having some problems with the fcntl() function.
> 
> I've written the following sample to demonstrate the problem:
> [SNIP]
> If I run this code in the same directory in two seperate shells I'd
> expect only the first instance to print 'No blocking lock' 
> however both do and the  second then goes on to block waiting for the
> actual lock (which it gets when I terminate the first instance). So
> the locking functionality works just fine; however the lock reporting
> does seem not to work and always returns F_UNLCK.
> 
> Can someone confirm if this is a known limittaion of the current
> version, a limitation of the underlying windows API or a bug?

It's a bug.  The original BSD code which the Cygwin code is based on
took a shortcut in a specific case, which is invalid for Cygwin.
I disabled this shaortcut and your testcase runs fine now.  I'll
prepare a new 1.7.0 testrelease in the next few days.

Thanks for the report and espcially thanks for the simple testcase.


Corinna

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

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