attribute data structure rewrite

[Joseph S. Myers]

On Fri, 24 Sep 2004, Giovanni Bajo wrote:

> Anothing thing I have been shown today is that we currently reject this:
> 
> ----------------------------------------
> #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.  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.

-- 
Joseph S. Myers               http://www.srcf.ucam.org/~jsm28/gcc/
  http://www.srcf.ucam.org/~jsm28/gcc/#c90status - status of C90 for GCC 4.0
    jsm@polyomino.org.uk (personal mail)
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