Newsgroups: comp.lang.c
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: Important Question
Message-ID: <1988Aug2.163756.17286@utzoo.uucp>
Organization: U of Toronto Zoology
References: <16680@brl-adm.ARPA> <1105@garth.UUCP>
Date: Tue, 2 Aug 88 16:37:56 GMT

In article <1105@garth.UUCP> smryan@garth.UUCP (Steven Ryan) writes:
>I do not know what the original noalias proposal was, but it was an attempt
>to implement some form of the alias ban.
>
>It is controversial because it is hard to come up with a runtime check
>of the alias ban...

Well, not really.  At least, this wasn't the reason why putting it in C
was controversial.  The X3J11 noalias proposal was controversial because
almost nobody understood it well, because it had all-pervading effects, 
because it was an X3J11 invention rather than a codification of prior
art, and above all because it was introduced at the last minute, at a
time when the draft standard was theoretically approaching stability,
yet was perceived to be a significant change whose implications were not
fully understood.

C probably does need some way of doing something about the aliasing problem,
and a revised noalias might perhaps be the way to do it (although I have my
doubts), but it will have to wait for the next revision of the standard
(by which time, one hopes, there will be some actual C experience with
experimental features along those lines).
-- 
MSDOS is not dead, it just     |     Henry Spencer at U of Toronto Zoology
smells that way.               | uunet!mnetor!utzoo!henry henry@zoo.toronto.edu