Re: type Foo_ptr in new void*;

[Darren New <dnew@san.rr.com>]

>  You can even create an array
> of Foo *. However, pointer arithmetic from the start of this array
> produces unspecified behavior. 

Errrr, no it doesn't.

> What is the sizeof Foo? 

Irrelevant, if you have an array of Foo*. If you have an array of Foo,
it's relevant.

> Since it is
> undefined, there is no correct answer to that question. Without a
> proper definition of the sizeof Foo, there can be no reliable pointer
> arithmetic.

Right. That's why you can't do pointer arithmetic on a Foo* without
defining Foo.

Which is not to say that Ada isn't superior to C in this respect. 

But what do you think a compiler is going to do if you index an array of
Foo without defining Foo? Just randomly make up a sizeof(Foo) from whole
cloth? There's probably something in the standard about this.

-- 
Darren New / Senior MTS & Free Radical / Invisible Worlds Inc.
San Diego, CA, USA (PST). Cryptokeys on demand. dnew@san.rr.com
          Only a WIMP puts wallpaper on his desktop.