Newsgroups: comp.lang.c
Path: utzoo!henry
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Expressions in initializers
Message-ID: <1991Mar8.164214.11287@zoo.toronto.edu>
Date: Fri, 8 Mar 1991 16:42:14 GMT
References: <1991Mar4.144939.8311@ux1.cso.uiuc.edu> <1032@caslon.cs.arizona.edu> <3599.27d3ca8a@iccgcc.decnet.ab.com> <2842@wn1.sci.kun.nl>
Organization: U of Toronto Zoology

In article <2842@wn1.sci.kun.nl> hansm@cs.kun.nl (Hans Mulder) writes:
>>So a conforming compiler is free to consider sqrt(2.0) to be a
>>compile-time constant.
>
>Nope.  The ANSI standard gives an exhaustive list of operators that
>can appear in a "constant expression" as required in an aggregate
>initialiser and function calls are not on the list.

Nope. :-)  3.4:  "An implementation may accept other forms of constant
expressions."  It is legitimate for an implementation to take that as
a constant expression, although the usage is not portable.

Incidentally, where did you find the "exhaustive list"?  K&R used to give
such a list (which had at least one error in it!), but the definition of
constant expressions in X3.159-1989 section 3.4 doesn't do it that way.
-- 
"But this *is* the simplified version   | Henry Spencer @ U of Toronto Zoology
for the general public."     -S. Harris |  henry@zoo.toronto.edu  utzoo!henry