From owner-freebsd-current@FreeBSD.ORG  Fri Dec 19 11:36:46 2003
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
Delivered-To: freebsd-current@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 50F5516A4CE
	for <current@freebsd.org>; Fri, 19 Dec 2003 11:36:46 -0800 (PST)
Received: from pandora.afflictions.org (asylum.afflictions.org [64.7.134.90])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 1851943D39
	for <current@freebsd.org>; Fri, 19 Dec 2003 11:36:44 -0800 (PST)
	(envelope-from dgerow@afflictions.org)
Received: from dementia.afflictions.org (dementia [172.16.0.56])
	by pandora.afflictions.org (Postfix) with ESMTP
	id C2E1B5CE53; Fri, 19 Dec 2003 15:03:38 -0500 (EST)
Received: by dementia.afflictions.org (Postfix, from userid 1001)
	id 2EAB86D447; Fri, 19 Dec 2003 09:36:56 -0500 (EST)
Date: Fri, 19 Dec 2003 09:36:56 -0500
From: Damian Gerow <dgerow@afflictions.org>
To: "M. Gamsjager" <maillist@cust.6.253.adsl.cistron.nl>,
	current@freebsd.org
Message-ID: <20031219143656.GD4155@afflictions.org>
References: <001a01c3c64e$621ccff0$6701a8c0@winxp>
	<mailman.1071862081.21906.fcurrent-l@lists.sentex.ca>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <mailman.1071862081.21906.fcurrent-l@lists.sentex.ca>
X-Operating-System: FreeBSD 5.2-BETA on a i386
X-GPG-Fingerprint: B3D7 D901 A53A 1A99 BFD6  E6DF 9F3B 742B C288 9CC9
User-Agent: Mutt/1.5.5.1i
Subject: Re: Compiling error in PAM
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
	<freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Fri, 19 Dec 2003 19:36:46 -0000

Thus spake Ulrich Spoerlein (q@uni.de) [19/12/03 14:27]:
: > i try to compile 5.2 (cvsed) on a 5.1 machine. When i do so i get this error:
: > 
: > /usr/src/lib/libpam/modules/pam_echo/pam_echo.c: In function `_pam_echo':
: > /usr/src/lib/libpam/modules/pam_echo/pam_echo.c:92: warning: dereferencing type-punned pointer will break strict-aliasing rules
: > *** Error code 1
: 
: You are not giving the command leading to this error, but I suspect it's
: because of CFLAGS=-02.
: 
: Please note that optimizations other than -O are NOT supported.

There was a lot of discussion about this not too long ago, and the
final conclusions was that while it is not supported, the PAM code is
actually breaking the strict aliasing rules.  For some reason, GCC only
picks this up when -O2 or higher is enabled.

I /think/ DES committed some code to fix the breakage, so it will now
compile with -O2, but the official stance is still: don't use -O2, it's
unsupported.