Path: utzoo!mnetor!uunet!husc6!purdue!umd5!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.lang.c
Subject: Re: "the integer constant zero"
Message-ID: <10976@mimsy.UUCP>
Date: 8 Apr 88 16:30:57 GMT
References: <570@mtxinu.UUCP> <10747@mimsy.UUCP> <7507@brl-smoke.ARPA> <1032@mcgill-vision.UUCP>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 32

>In article <10754@mimsy.UUCP> chris@mimsy.UUCP (Chris Torek) writes:
>>[...] the integer constant `0' in a pointer context [...].  What is
>>`the integer constant 0'?

In article <1032@mcgill-vision.UUCP> mouse@mcgill-vision.UUCP
(der Mouse) writes:
>"the integer constant zero" is not necessarily the same as "an integer
>constant expression zero".

My copy (or rather, Fred's copy, which I borrowed) of the draft
standard is Elsewhere at the moment, but what was `clear' to me
(constant 0 => expression that evaluates as a constant and to 0) was
apparently `clear' to X3J11 as well, because that was what the draft
said.

Now, however, there seems to be some sentiment to rephrase it.
Among other problems,

	int *p;
	p = 1 ? (void *)0 : (void *)0;

is not quite legal, even though

	p = 1 ? 0 : 0;

is!

This sort of nasty fiddly detail is what makes getting standards
right so hard.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris