From owner-freebsd-hackers@FreeBSD.ORG  Wed Jul  6 16:36:21 2005
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
X-Original-To: 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 3030B16A41C
	for <freebsd-hackers@FreeBSD.ORG>; Wed,  6 Jul 2005 16:36:20 +0000 (GMT)
	(envelope-from reidrac@usebox.net)
Received: from blackshell.usebox.net (84-120-176-87.onocable.ono.com
	[84.120.176.87])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 5780543D45
	for <freebsd-hackers@FreeBSD.ORG>; Wed,  6 Jul 2005 16:36:19 +0000 (GMT)
	(envelope-from reidrac@usebox.net)
Received: from [192.168.0.1] (fixed-1-lan.blackshell.usebox.net [192.168.0.1])
	by blackshell.usebox.net (8.13.0/8.13.0) with ESMTP id
	j66GaAxX018950; Wed, 6 Jul 2005 18:36:10 +0200 (CEST)
From: "Juan J." =?ISO-8859-1?Q?Mart=EDnez?= <reidrac@usebox.net>
To: Matt <mhersant@comcast.net>
In-Reply-To: <42518AC9.5070208@comcast.net>
References: <42518AC9.5070208@comcast.net>
Content-Type: text/plain; charset=ISO-8859-1
Date: Wed, 06 Jul 2005 18:36:09 +0200
Message-Id: <1120667769.8695.10.camel@localhost.localdomain>
Mime-Version: 1.0
X-Mailer: Evolution 2.2.1.1 
Content-Transfer-Encoding: 8bit
X-Mailman-Approved-At: Thu, 07 Jul 2005 12:11:06 +0000
Cc: freebsd-hackers@FreeBSD.ORG, misc@openbsd.org
Subject: Re: C programming question
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.5
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: Wed, 06 Jul 2005 16:36:21 -0000

El lun, 04-04-2005 a las 11:43 -0700, Matt escribió:
> [...]
> Can someone break down these declarations (if that's what they are)?  Is 
> this a form of typecasting?  Thanks for your help.

Those are declarations of pointers to functions.

/* real function */
void dumb(int a) { return a; }
...

/* here follows a declaration of func pointer */
int (*func_ptr)(int);
int a;

/* assign it */
func_ptr=dumb;

/* use it */
a=func_ptr(123);

Any good book about C should cover this. Look for OOP in C also, it's
frequent use pointers to functions + structs to add classes to C.

regards,

Juanjo

-- 
Desarrollo y sistemas: http://www.usebox.net/
      Página Personal: http://www.usebox.net/jjm/