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Date: Thu, 6 Jan 2005 18:10:30 -0500 (EST)
From: Igor Pechtchanski <pechtcha AT cs DOT nyu DOT edu>
Reply-To: cygwin AT cygwin DOT com
To: claude DOT roblez AT free DOT fr
cc: cygwin AT cygwin DOT com
Subject: Re: timer_create / POSIX non conformance ?
In-Reply-To: <1105023198.41dd50de2221a@imp5-q.free.fr>
Message-ID: <Pine.GSO.4.61.0501061808560.26844@slinky.cs.nyu.edu>
References: <1105023198 DOT 41dd50de2221a AT imp5-q DOT free DOT fr>
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Content-Type: TEXT/PLAIN; charset=US-ASCII

On Thu, 6 Jan 2005, claude.roblez wrote:

> >>The problem appears with the [timer_create] function called with a [sigevent]
> >>structure having its [sigev_notify] member set to [SIGEV_THREAD].
> >>In this case, the function pointed to by the [sigev_notify_function] member is
> >>prototyped [void(*)(union sigval)] and should receive the [sigev_value] member.
> >>(according to "The Open Group Base Specifications Issue 6 IEEE Std 1003.1, 2004
> >>Edition")
> >>On various Linux systems (Debian, Fedora...), the behaviour is appropriate.
> >>
> >>Under Cygwin, in order to perform correctly, I have to declare my function :
> >static void SignalTimer(union sigval *sig)
> >instead of : static void SignalTimer(union sigval sig).
> >>Actually, the function receives a pointer to the sigev_value member rather than
> >>the union itself.
> >>
> >>I had a glance at the cygwin source code (file: timer.cc)
> >>
> >>	case SIGEV_THREAD:
> >>	  {
> >>	    pthread_t notify_thread;
> >>	    debug_printf ("%p starting thread", x);
> >>	    int rc = pthread_create (&notify_thread,
> >>tt.evp.sigev_notify_attributes,(void * (*) (void *))
> >>tt.evp.sigev_notify_function,&tt.evp.sigev_value);
> >>
> >>The last argument: [&tt.evp.sigev_value] is probably wrong (passing an address)
> >
> >I changed this code as per the patch below.  Thanks for pinpointing
> >where it was going wrong.
> >
> >A snapshot is being generated even as I type.
> >
> >cgf
> >
> >Index: timer.cc
> >===================================================================
> >RCS file: /cvs/src/src/winsup/cygwin/timer.cc,v
> >retrieving revision 1.3
> >diff -u -p -r1.3 timer.cc
> >--- timer.cc    26 Nov 2004 04:15:09 -0000      1.3
> >+++ timer.cc    6 Jan 2005 14:08:03 -0000
> >>@@ -133,7 +133,7 @@ timer_thread (VOID *x)
> >            debug_printf ("%p starting thread", x);
> >            int rc = pthread_create (&notify_thread, tt.evp.sigev_notify_attributes,
> >                                     (void * (*) (void *)) tt.evp.sigev_notify_function,
> >-                                    &tt.evp.sigev_value);
> >+                                    tt.evp.sigev_value.sival_ptr);
> >            if (rc)
> >              {
> >                debug_printf ("thread creation failed, %E");
>
>
> As far as I can see, the latest snapshot (2005-Jan-06) solves the problem
> (extensive testing will follow).
>
> Thank you for your incredibly fast reply and snapshot delivery.
>
> Claude Roblez

I'm sure not having to debug the code had something to do with it. ;-)
	Igor
-- 
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     |,4-  ) )-,_. ,\ (  `'-'		Igor Pechtchanski, Ph.D.
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