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Path: utzoo!watmath!wateng!padpowell
From: padpowell@wateng.UUCP (PAD Powell)
Newsgroups: net.lang.c
Subject: proposed new construct, offsetof()
Message-ID: <1583@wateng.UUCP>
Date: Wed, 24-Oct-84 10:24:28 EDT
Article-I.D.: wateng.1583
Posted: Wed Oct 24 10:24:28 1984
Date-Received: Thu, 25-Oct-84 02:40:32 EDT
Organization: U of Waterloo, Ontario
Lines: 20

I have just been burned again, by a C compiler, and a structure.

I propose the following construct to be added to C:

offsetof( structure_name.field.field.... )

Given the name of the stucture, and the list of the fields, returns the
integer value of the offset from the beginning of the structure, that
will be used in accessing the particular field.

1.  This is useful in DEBUGGING, and finding if you have portable code.
	I have just been burned with 16/32 bit integers.
2.  It provides a "hook" into the compiler which will eliminate all the
	ugly arguements about "offset calculations using 0 pointers"
	which is raging.
3.  In my personal opinion, it is a solution to a problem that requires
	looking at object code, and then guessing what the offset is.

Patrick ("Whimper! first the optimizer gets me, now the structures")
	Powell