Path: utzoo!mnetor!uunet!mcvax!ukc!eagle!icdoc!cam-cl!am
From: am@cl.cam.ac.uk (Alan Mycroft)
Newsgroups: comp.lang.c
Subject: Re: ! operator in constant expressions
Message-ID: <1132@jenny.cl.cam.ac.uk>
Date: 29 Jan 88 15:59:57 GMT
References: <3813@hoptoad.uucp> <660003@hpclsue.HP.COM>
Reply-To: am@cl.cam.ac.uk (Alan Mycroft)
Organization: U of Cambridge Comp Lab, UK
Lines: 23

I hope the public review draft is a little more precise....

In article <660003@hpclsue.HP.COM> sue@hpclsue.HP.COM (Sue Meloy) writes:
>According to the latest ANSI draft:
>A constant expression used in a static initializer must evaluate to one of
****                                                     ^^^^^^^^ Duh?
>the following:
>    an arithmetic constant expression
>        only arithmetic operands; casts can only be from arithmetic type to
>        arithmetic type.
>    an address constant
>	created via & or by use of an array or function name
****                                                    ^^^^
0. Presumably static.
1. Or array expression?   Consider
         static struct { int a, b[5]; } x;  int *p = x.b;
2. Presumably all subscripts must be arith. const. exprs?
3. What about  static int a,*b = &*&a;
>    an address constant plus or minus an integral constant expression
****
0. Presumably this applies recursively so that
         static int a[10], *b = (&a[0] + 6) - 4;
   is OK?