Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!uunet!mcsun!ukc!mrccrc!dcurtis
From: dcurtis@crc.ac.uk (Dr. David Curtis)
Newsgroups: comp.lang.c
Subject: Re: Need macro to get offset within a structure
Message-ID: <493@tin.crc.ac.uk>
Date: 21 Feb 91 12:43:31 GMT
References: <1991Feb16.232713.6001@runx.oz.au>
Reply-To: dcurtis@crc.ac.uk (Dr. David Curtis)
Organization: MRC Human Genome Resource Centre
Lines: 8

In article <1991Feb16.232713.6001@runx.oz.au> richardm@runx.oz.au (Richard Murnane) writes:
>Hi all,
>Does anybody know a decent macro to find the offset of an element
>in a structure?

How about:

#define offset(str,el) ((char*) &((str*)NULL)->el - (char*) NULL)