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From: jpn@teddy.UUCP
Newsgroups: comp.arch
Subject: Re: Aliasing, etc. in C (available no. of registers)
Message-ID: <3720@teddy.UUCP>
Date: Wed, 28-Jan-87 16:50:33 EST
Article-I.D.: teddy.3720
Posted: Wed Jan 28 16:50:33 1987
Date-Received: Fri, 30-Jan-87 00:44:54 EST
References: <7803@decwrl.DEC.COM>
Reply-To: jpn@teddy.UUCP (John P. Nelson)
Organization: GenRad, Inc., Concord, Mass.
Lines: 20

>Oh?  If this is aberrant coding, you might want to look at your
>varargs.h file whose operation relies on these assumptions; and this is
>in the ANSI proposal.

Sigh....   Varargs is DEFINED as being machine-dependent - in other words,
those varargs macros/functions may have to be rewritten for every machine -
it is up to the system providers to provide definitions that work for a
SINGLE machine:  the one that is being compiled for.  Any user code that
does this is not portable.

>>>	int a,b, *ptr;
>>>
>>>	ptr = &a;
>>>	ptr++;
>>>	/* ptr now points to b */

Any program that is expected to work on more than one machine MUST NOT
make assumptions about memory layout.  This is the reason why varargs
exists:  So that 100's of programs do not have to make such assumptions!
Sure, this is legal C, but the trailing comment is NOT NECESSARILY TRUE!