Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner AT cygwin DOT com Delivered-To: mailing list cygwin AT cygwin DOT com Date: Tue, 26 Feb 2002 01:13:05 -0500 From: Christopher Faylor To: cygwin AT cygwin DOT com Subject: Re: sem_trywait returns EAGAIN (rather than returning -1 and setting errno) Message-ID: <20020226061305.GA7735@redhat.com> Reply-To: cygwin AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com References: <005d01c1be6d$b9c6a2c0$6401a8c0 AT dopeslap2k> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <005d01c1be6d$b9c6a2c0$6401a8c0@dopeslap2k> User-Agent: Mutt/1.3.23.1i On Mon, Feb 25, 2002 at 09:31:41PM -0500, Andrew T. Schnable wrote: >I was doing some pthreads/semaphore work and I tracked down a problem >in my code to a bug in sem_trywait. Posix sem_trywait is defined as >returning -1 and setting errno to EAGAIN if the semaphore would have >blocked. The cygwin implementation returns EAGAIN an leaves errno >unchanged. > >Has anyone else encountered this problem and provided a fix? Hmm. Unless I am missing something, it looks like this problem is prevalent in the pthreads code. It makes me think that maybe the author meant to catch these kinds of things in the interface between the __pthread/pthread calls. Robert, can you explain what's going on here? cgf >Andy >schnable AT enteract DOT com > >PS. The problem seems to be in thread.cc (semaphore::TryWait) - I don't see >much >stderr setting anywhere in this file - is this verboten - or just >overlooked? > > >int >semaphore::TryWait () >{ > /*FIXME: signals should be able to interrupt semaphores... > *We probably need WaitForMultipleObjects here. > */ > if (WaitForSingleObject (win32_obj_id, 0) == WAIT_TIMEOUT) > return EAGAIN; > currentvalue--; > return 0; >} -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Bug reporting: http://cygwin.com/bugs.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/