From owner-freebsd-hackers@FreeBSD.ORG  Thu May  1 08:37:41 2003
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP
	id 0CC4937B401; Thu,  1 May 2003 08:37:41 -0700 (PDT)
Received: from haldjas.folklore.ee (Haldjas.folklore.ee [193.40.6.121])
	by mx1.FreeBSD.org (Postfix) with ESMTP
	id CDC1A43F85; Thu,  1 May 2003 08:37:36 -0700 (PDT)
	(envelope-from narvi@haldjas.folklore.ee)
Received: from haldjas.folklore.ee (localhost [127.0.0.1])
	by haldjas.folklore.ee (8.12.3/8.11.3) with ESMTP id h41FbZ6U001033;
	Thu, 1 May 2003 18:37:35 +0300 (EEST)
	(envelope-from narvi@haldjas.folklore.ee)
Received: from localhost (narvi@localhost)h41FbZwd001030;
	Thu, 1 May 2003 18:37:35 +0300 (EEST)
Date: Thu, 1 May 2003 18:37:35 +0300 (EEST)
From: Narvi <narvi@haldjas.folklore.ee>
To: "Jacques A. Vidrine" <nectar@freebsd.org>
In-Reply-To: <20030501150713.GA34992@madman.celabo.org>
Message-ID: <20030501181950.G40030-100000@haldjas.folklore.ee>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
cc: hackers@freebsd.org
cc: Dag-Erling Smorgrav <des@ofug.org>
Subject: Re: incorrect enum warning?
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 01 May 2003 15:37:41 -0000


On Thu, 1 May 2003, Jacques A. Vidrine wrote:

> On Thu, May 01, 2003 at 04:51:40PM +0200, Dag-Erling Smorgrav wrote:
> > Why does the following code in OpenPAM headers:
> >
> > /*
> >  * XSSO 5.4
> >  */
> > enum {
> >         PAM_SILENT                      = 0x80000000,
> >         PAM_DISALLOW_NULL_AUTHTOK       = 0x1,
> >         PAM_ESTABLISH_CRED              = 0x1,
> >         PAM_DELETE_CRED                 = 0x2,
> >         PAM_REINITIALIZE_CRED           = 0x4,
> >         PAM_REFRESH_CRED                = 0x8,
> >         PAM_PRELIM_CHECK                = 0x1,
> >         PAM_UPDATE_AUTHTOK              = 0x2,
> >         PAM_CHANGE_EXPIRED_AUTHTOK      = 0x4
> > };
> >
> > cause the following warning when compiled with CSTD=c99:
> >
> > /usr/src/contrib/openpam/include/security/pam_constants.h:100: warning: ISO C restricts enumerator values to range of `int'
> >
> > when 0x80000000 is clearly within the range of 'int' on all platforms
> > we support?
>
> Guessing:
> C does not specify one's complement or two's complement representation
> of integers.  On a one's complement 32-bit platform, 0x80000000 is -0
> (negative zero), which cannot be an `int'.
>

-0 would be a valid int on a one's complement platform It would probably
compare equal to zero. Gcc only runs on 2-s complement platforms anyways.

> Cheers,
> --
> Jacques Vidrine   . NTT/Verio SME      . FreeBSD UNIX       . Heimdal
> nectar@celabo.org . jvidrine@verio.net . nectar@freebsd.org . nectar@kth.se
>