From owner-freebsd-questions@FreeBSD.ORG  Sun Aug  1 23:30:34 2004
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
Delivered-To: freebsd-questions@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 71B7916A4CE
	for <questions@freebsd.org>; Sun,  1 Aug 2004 23:30:34 +0000 (GMT)
Received: from ns1.tcbug.org (12-218-40-24.client.mchsi.com [12.218.40.24])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 39DBD43D1D
	for <questions@freebsd.org>; Sun,  1 Aug 2004 23:30:32 +0000 (GMT)
	(envelope-from friar_josh@tcbug.org)
Received: from [10.0.0.10] (unknown [10.0.0.10])
	by ns1.tcbug.org (Postfix) with ESMTP id CCE4EBA53
	for <questions@freebsd.org>; Sun,  1 Aug 2004 18:30:44 -0500 (CDT)
From: Josh Paetzel <friar_josh@tcbug.org>
To: questions@freebsd.org
Date: Sun, 1 Aug 2004 18:29:58 -0500
User-Agent: KMail/1.6.1
MIME-Version: 1.0
Content-Disposition: inline
Content-Type: text/plain;
  charset="us-ascii"
Content-Transfer-Encoding: 7bit
Message-Id: <200408011829.58952.friar_josh@tcbug.org>
Subject: Way OT programming question
X-BeenThere: freebsd-questions@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: User questions <freebsd-questions.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>,
	<mailto:freebsd-questions-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-questions>
List-Post: <mailto:freebsd-questions@freebsd.org>
List-Help: <mailto:freebsd-questions-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>,
	<mailto:freebsd-questions-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sun, 01 Aug 2004 23:30:34 -0000

I've been muddling through some of the source files for FreeBSD 
5.2.1-RELEASE, and I've noticed that a large number of .c files 
in /usr/src have something similar to below in them:

#ifndef lint
#if 0
static char sccsid[] = "@(#)cat.c       8.2 (Berkeley) 4/27/95";
#endif
#endif /* not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/bin/cat/cat.c,v 1.29 2003/04/30 17:40:28 
obrien Exp $");

1) Isn't 'if 0' always negative?
2) What is the __FBSDID line doing?

-- 
Thanks,

Josh Paetzel