Re: type Foo_ptr in new void*;

[James Rogers <jimmaureenrogers@worldnet.att.net>]

"Warren W. Gay VE3WWG" wrote:
> 
> I don't think your "unspecified behavior" assertion is truly fair here.
> I believe that when you reach a point in the C/C++ compile where
> pointer arithmetic is required on the "undefined type", you will get
> a compile error. The compiler will not generate code that does
> "undefined behaviour" here. If there is any further doubt about it,
> I am sure this can be tested with a short example program.

Your assertion may be true for C++ compilers, but it was not true
for C compilers in the early 1990s.

> Ada does permit you to define an incomplete type as well, but the
> condition is that it must be defined eventually. I agree that enforcing
> its later definition, is a good thing.

Let's be a little more precise here. Ada does not allow you to define
incomplete types. It allows you to define unconstrained types.
There is a real difference. All Ada objects are fully defined.
You cannot make an unconstrained instance of an unconstrained type.

Jim Rogers
Colorado Springs, Colorado USA