Path: utzoo!attcan!uunet!snorkelwacker!bloom-beacon!LARRY.MCRCIM.MCGILL.EDU!mouse
From: mouse@LARRY.MCRCIM.MCGILL.EDU (der Mouse)
Newsgroups: comp.windows.x
Subject: Re: XtOffset implementation problem
Message-ID: <9006270654.AA01467@Larry.McRCIM.McGill.EDU>
Date: 27 Jun 90 06:54:52 GMT
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 16

[trying to find an XtOffset that works on a certain compiler]
>> #define XtOffset(T,M) (int)(char *)&((T)0)->M
>> #define XtOffset(T,M) ((char *)&((T)0)->M - (char *)0)
>> static int foo;
>> #define XtOffset(T,M) ((char *)&((T)&foo)->M - (char *)&foo)

> I have a litle difficulty understanding these.  Why the `0' following
> `(T)' in the first two, and the `&foo' following `(T)' in the second.

The T argument is expected to be a type (a struct pointer type), not an
object of any sort.

					der Mouse

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