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Date:      04 Jun 2003 23:07:25 +0200
From:      Kern Sibbald <kern@sibbald.com>
To:        Julian Elischer <julian@elischer.org>
Cc:        freebsd-threads@freebsd.org
Subject:   Re: FreeBSD pthread_equal "bug"
Message-ID:  <1054760845.13630.568.camel@rufus>
In-Reply-To: <Pine.BSF.4.21.0306041319370.2846-100000@InterJet.elischer.org>
References:  <Pine.BSF.4.21.0306041319370.2846-100000@InterJet.elischer.org>

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I like that word "robustness" :-)

On Wed, 2003-06-04 at 22:20, Julian Elischer wrote:
> On Wed, 4 Jun 2003, Julian Elischer wrote:
> 
> > in fact The first paragraph of:
> 
> uh, not the first parageaph.. the paragraph marked "Thread IDs"
> (didn't notice the page was scrolled up a bit)
> 
> > 
> >  http://www.opengroup.org/onlinepubs/007904975/toc.htm
> > 
> > States this..
> > 
> > 
> > On Wed, 4 Jun 2003, Julian Elischer wrote:
> > 
> > > 
> > > 
> > > On Wed, 4 Jun 2003, Jeff Roberson wrote:
> > > 
> > > > On 4 Jun 2003, Kern Sibbald wrote:
> > > > 
> > > > >
> > > > > I'm not sure what the POSIX specification says,
> > > > > if I were programming it, I would not be content
> > > > > with the FreeBSD current implementation especially
> > > > > considering that both Solaris and Linux do it "correctly".
> > > > 
> > > > Would you rather your application failed immediately, or in a subtle,
> > > > unexpected way after many hours/weeks/months of run time?  Dan says the
> > > > standard allows for immediate reuse.  If that is correct, then Solaris,
> > > > linux, and FreeBSD all do it correctly for the only definition of
> > > > correctly that matters.
> > > > 
> > > > Simply adding an ID is problematic because the ids will wrap.  Without
> > > > using some deterministic notification you can't be sure that it isn't an
> > > > expired thread.
> > > 
> > > 
> > > I will quote from "Programming with Posix threads"
> > > by David R Butenhof..
> > > He is one o fthe main authors of the Posix threads standard so 
> > > I tend to treat this book as a guide..
> > > 
> > > "Once a thread is recycled, the thread's ID (pthread_t) is no longer
> > > valid. You cannot join with the thread, canel it, or anything else. The
> > > terminated thread's ID (which may be the addess of a system data
> > > structure) may be assigned to a new thread. Instead of receiving an
> > > ESRCH failure from your call to pthread_cancel, you would instead cancel
> > > a different thread."
> > > 
> > > I think that is pretty explicit as far as expected bahaviour.
> > > 
> > > HAVING SAID THAT, it is not impossible that at some time in the future
> > > we may use some other pthread_t type, e.g an incrementing TID,
> > > but at this time I think we are well within the standard...
> > > 
> > > 
> > > Julian
> > > 
> > > 
> > > _______________________________________________
> > > freebsd-threads@freebsd.org mailing list
> > > http://lists.freebsd.org/mailman/listinfo/freebsd-threads
> > > To unsubscribe, send any mail to "freebsd-threads-unsubscribe@freebsd.org"
> > > 
> > 
> > _______________________________________________
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> > 



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