From owner-freebsd-hackers  Fri Sep 14  5: 3:24 2001
Delivered-To: freebsd-hackers@freebsd.org
Received: from peter3.wemm.org (c1315225-a.plstn1.sfba.home.com [24.14.150.180])
	by hub.freebsd.org (Postfix) with ESMTP
	id 8D1D537B405; Fri, 14 Sep 2001 05:03:20 -0700 (PDT)
Received: from overcee.netplex.com.au (overcee.wemm.org [10.0.0.3])
	by peter3.wemm.org (8.11.0/8.11.0) with ESMTP id f8EC3KM78670;
	Fri, 14 Sep 2001 05:03:20 -0700 (PDT)
	(envelope-from peter@wemm.org)
Received: from wemm.org (localhost [127.0.0.1])
	by overcee.netplex.com.au (Postfix) with ESMTP
	id 25BB5380A; Fri, 14 Sep 2001 05:03:20 -0700 (PDT)
	(envelope-from peter@wemm.org)
X-Mailer: exmh version 2.3.1 01/18/2001 with nmh-1.0.4
To: tlambert2@mindspring.com
Cc: Mike Smith <msmith@FreeBSD.ORG>, Yar Tikhiy <yar@FreeBSD.ORG>,
	hackers@FreeBSD.ORG, msmith@mass.dis.org
Subject: Re: Driver structures & alignment 
In-Reply-To: <3BA1C819.65D72D4B@mindspring.com> 
Date: Fri, 14 Sep 2001 05:03:20 -0700
From: Peter Wemm <peter@wemm.org>
Message-Id: <20010914120320.25BB5380A@overcee.netplex.com.au>
Sender: owner-freebsd-hackers@FreeBSD.ORG
Precedence: bulk
List-ID: <freebsd-hackers.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-hackers>
List-Unsubscribe: <mailto:majordomo@FreeBSD.ORG?subject=unsubscribe%20freebsd-hackers>
X-Loop: FreeBSD.ORG

Terry Lambert wrote:
> Mike Smith wrote:
> > Having said that, I recommend using __attribute__ ((packed))
> > to explicitly request that a structure be packed.
> 
> Is there a problem with "#pragma pack(1)"?  I see it in a
> lot of header files... do they need changing?

Yes, but it should be:
#define __packed __attribute__((packed))
in sys/cdefs.h.

This allows us to provide an alternative __packed implementation for some
other mythical compiler some day.

The same goes for __format_arg(n) in stdio.h.  And so on.  We've been pretty
clean about it so far, but a few have slipped through.

Cheers,
-Peter
--
Peter Wemm - peter@FreeBSD.org; peter@yahoo-inc.com; peter@netplex.com.au
"All of this is for nothing if we don't go to the stars" - JMS/B5


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