From owner-freebsd-arch  Fri Jan 11 12:50:41 2002
Delivered-To: freebsd-arch@freebsd.org
Received: from albatross.prod.itd.earthlink.net (albatross.mail.pas.earthlink.net [207.217.120.120])
	by hub.freebsd.org (Postfix) with ESMTP id 19A6A37B405
	for <arch@freebsd.org>; Fri, 11 Jan 2002 12:50:38 -0800 (PST)
Received: from pool0189.cvx21-bradley.dialup.earthlink.net ([209.179.192.189] helo=mindspring.com)
	by albatross.prod.itd.earthlink.net with esmtp (Exim 3.33 #1)
	id 16P8d7-0006zq-00; Fri, 11 Jan 2002 12:50:26 -0800
Message-ID: <3C3F500E.A1736EC0@mindspring.com>
Date: Fri, 11 Jan 2002 12:50:22 -0800
From: Terry Lambert <tlambert2@mindspring.com>
X-Mailer: Mozilla 4.7 [en]C-CCK-MCD {Sony}  (Win98; U)
X-Accept-Language: en
MIME-Version: 1.0
To: Nate Williams <nate@yogotech.com>
Cc: Bruce Evans <bde@zeta.org.au>,
	Daniel Eischen <eischen@pcnet1.pcnet.com>,
	Dan Eischen <eischen@vigrid.com>, Peter Wemm <peter@wemm.org>,
	Archie Cobbs <archie@dellroad.org>, Alfred Perlstein <bright@mu.org>,
	arch@FreeBSD.ORG
Subject: Re: Request for review: getcontext, setcontext, etc
References: <20020112054041.J3330-100000@gamplex.bde.org>
		<3C3F455B.86856045@mindspring.com> <15423.17965.472722.218250@caddis.yogotech.com>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Sender: owner-freebsd-arch@FreeBSD.ORG
Precedence: bulk
List-ID: <freebsd-arch.FreeBSD.ORG>
List-Archive: <http://docs.freebsd.org/mail/> (Web Archive)
List-Help: <mailto:majordomo@FreeBSD.ORG?subject=help> (List Instructions)
List-Subscribe: <mailto:majordomo@FreeBSD.ORG?subject=subscribe%20freebsd-arch>
List-Unsubscribe: <mailto:majordomo@FreeBSD.ORG?subject=unsubscribe%20freebsd-arch>
X-Loop: FreeBSD.ORG

Nate Williams wrote:
> > > I'm not saying any more, since I have made negative progress attempting
> > > to explain this.
> >
> > In other words, SIGFPE is about as trappable as SIGBUS or SIGILL,
> > and means about the same thing: an unrecoverable fault.
> 
> It correctly works in single threaded programs in FreeBSD 2.2, but not
> in 4.4.

I think this is the code that was ripped out which made the 386
happy.


> > If you think about it a little, since you can't guarantee delivery
> > of signals to particular threads anyway, it makes sense that SIGFPE
> > would not be useful under any circumstances in threaded programs,
> > no matter how you sliced it.
> 
> What Bruce is saying is that it's not possible to deliver the signal *AT
> ALL*, let alone in threaded programs.  However, he contradicts his own
> statements in later parts of the same email, hence the confusion.

I think there is still some confusion about "FPE" occuring vs.
"SIGFPE" being raised.

I think he's saying that it's possible, but never useful to deliver
it.

-- Terry

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-arch" in the body of the message