From: "Giovanni Bajo" <giovannibajo@libero.it>
To: "Joseph S. Myers" <jsm@polyomino.org.uk>
Cc: "Gabriel Dos Reis" <gdr@cs.tamu.edu>, <gcc@gcc.gnu.org>
Subject: Re: attribute data structure rewrite
Date: Fri, 24 Sep 2004 14:45:00 -0000 [thread overview]
Message-ID: <02ae01c4a229$cda77880$dc4e2a97@bagio> (raw)
In-Reply-To: <Pine.LNX.4.61.0409240833430.2844@digraph.polyomino.org.uk>
Joseph S. Myers wrote:
>> ----------------------------------------
>> #include <stddef.h>
>> #include <stdio.h>
>>
>> struct A { char foo[10]; };
>>
>> void bar(void) {
>> int i;
>> for (i=0;i<10;i++)
>> printf("%d\n", offsetof(struct A, foo[i]));
>> }
>> --------------------------------------
>>
>> but we used to accept it. Any idea about its legality? Workarounds?
>
> Compile-time undefined for both C and C++, no diagnostic required; one
> couldn't reasonably be given with the old macro implementations.
Yes. Actually, the old implementation just worked.
> Either diagnose the use of non-integer-constant-expressions in
> offsetof, or permit them but make them cause the result not to be an
> integer constant expression.
I think we currently go with the former. But I believe this to be a regression
in user experience. Using the external + sizeof(i)*blah is ugly. If it was
possible to build the result not being an integer constant expression before
4.0 it would be great. If you want, I can file a bug report to track this.
--
Giovanni Bajo
next prev parent reply other threads:[~2004-09-24 11:29 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-24 0:15 Geoffrey Keating
2004-09-24 0:34 ` Andrew Pinski
2004-09-24 1:30 ` Joseph S. Myers
2004-09-24 1:47 ` Zack Weinberg
2004-09-24 6:52 ` Geoffrey Keating
2004-09-24 1:40 ` Gabriel Dos Reis
2004-09-24 2:34 ` Giovanni Bajo
2004-09-24 2:59 ` Gabriel Dos Reis
2004-09-24 4:17 ` Giovanni Bajo
2004-09-24 4:18 ` Gabriel Dos Reis
2004-09-24 8:40 ` Andreas Schwab
2004-09-24 8:40 ` Andreas Schwab
2004-09-24 9:17 ` Joseph S. Myers
2004-09-24 14:45 ` Giovanni Bajo [this message]
2004-09-24 8:36 ` Geoffrey Keating
2004-09-24 14:03 ` Joseph S. Myers
2004-09-24 2:35 ` Giovanni Bajo
2004-09-24 8:33 ` Geoffrey Keating
2004-09-24 12:24 ` Nathan Sidwell
2004-09-24 22:29 ` Mark Mitchell
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