From owner-freebsd-arch@FreeBSD.ORG  Wed Dec 22 09:08:57 2004
Return-Path: <owner-freebsd-arch@FreeBSD.ORG>
Delivered-To: freebsd-arch@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP
	id D4CBA16A4CE; Wed, 22 Dec 2004 09:08:57 +0000 (GMT)
Received: from mail25.syd.optusnet.com.au (mail25.syd.optusnet.com.au
	[211.29.133.166])	by mx1.FreeBSD.org (Postfix) with ESMTP
	id 2E9B043D45; Wed, 22 Dec 2004 09:08:57 +0000 (GMT)
	(envelope-from PeterJeremy@optushome.com.au)
Received: from cirb503493.alcatel.com.au
	(c211-30-75-229.belrs2.nsw.optusnet.com.au [211.30.75.229])
	iBM98thj001700
	(version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO);
	Wed, 22 Dec 2004 20:08:56 +1100
Received: from cirb503493.alcatel.com.au (localhost.alcatel.com.au
	[127.0.0.1])iBM98txP004497;	Wed, 22 Dec 2004 20:08:55 +1100 (EST)
	(envelope-from pjeremy@cirb503493.alcatel.com.au)
Received: (from pjeremy@localhost)iBM98t4O004496;
	Wed, 22 Dec 2004 20:08:55 +1100 (EST)	(envelope-from pjeremy)
Date: Wed, 22 Dec 2004 20:08:55 +1100
From: Peter Jeremy <PeterJeremy@optushome.com.au>
To: "Greg 'groggy' Lehey" <grog@freebsd.org>
Message-ID: <20041222090855.GO79646@cirb503493.alcatel.com.au>
References: <20041222010143.GS53357@wantadilla.lemis.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20041222010143.GS53357@wantadilla.lemis.com>
User-Agent: Mutt/1.4.2i
cc: FreeBSD Architecture Mailing List <arch@freebsd.org>
Subject: Re: Header files with enums instead of defines?
X-BeenThere: freebsd-arch@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Discussion related to FreeBSD architecture
	<freebsd-arch.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arch>,
	<mailto:freebsd-arch-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-arch>
List-Post: <mailto:freebsd-arch@freebsd.org>
List-Help: <mailto:freebsd-arch-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arch>,
	<mailto:freebsd-arch-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 22 Dec 2004 09:08:58 -0000

On Wed, 2004-Dec-22 11:31:43 +1030, Greg 'groggy' Lehey wrote:
>Has anybody thought about replacing #defines with enums in header
>files?  It would make debugging a whole lot easier.  Foe example, I'm
>currently looking at a debug printout which contains:
>
>  xerrno = 17, 
...
>  xerrno = EEXIST, 

K&R2 states that errno is an "integer expression" and that the error
values are "macros".  I suspect POSIX and newer C standards say something
similar.  Also, the enum value name replacement would only occur if xerrno
was of the appropriate enum type - which would make the code non-portable.

An alternative suggestion for you: Write a gdb macro which takes an
int and prints it as an errno.  Something like a shorthand version of:
  print (enum { EPERM=1, ENOENT=2, ..., EILSEQ=86})xerrno
should work.

You would probably write a [insert scripting language of choice] script
to convert <errno.h> into the appropriate gdb macro.

-- 
Peter Jeremy