Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!paperboy!osf.org!dbrooks
From: dbrooks@osf.org (David Brooks)
Newsgroups: comp.lang.c
Subject: Re: finding offset of a member in C structures
Message-ID: <22051@paperboy.OSF.ORG>
Date: 21 May 91 14:13:58 GMT
References: <1276@unisql.UUCP> <16194@smoke.brl.mil> <1991May20.212338.24349@thyme.jpl.nasa.gov> <16211@smoke.brl.mil>
Sender: news@OSF.ORG
Organization: Open Software Foundation
Lines: 16

In article <16211@smoke.brl.mil>, gwyn@smoke.brl.mil (Doug Gwyn) writes:
|> In article <1991May20.212338.24349@thyme.jpl.nasa.gov> kaleb@thyme.jpl.nasa.gov (Kaleb Keithley) writes:
|> >Here's how *they* do in the X Window System.  I expect it's about as
|> >portable as anything gets.
|> 
|> Wrong!  I posted a portable method.

The method you posted:
	struct a_struct foo;
	int offset2 = (char *)&foo.member2 - (char *)&foo; /* for example */

has an unfortunate drawback.  You need to be able to declare foo, and
squander space for it.  The ubiquitous uses in X don't have those luxuries.
-- 
David Brooks				dbrooks@osf.org
Systems Engineering, OSF		uunet!osf.org!dbrooks