Re: Reference to void

"James Kanze" <>
26 Oct 2006 11:38:28 -0400
Lucian Radu Teodorescu wrote:

Salt_Peter wrote:

Is the following code valid?

int i = 5;
void* pv = &i;
void& rv = *pv; // Error here on VC 2005

If not, why isn't it valid?

Its not valid for the same reasons that the following is invalid:
void v = 5;
That is to say: a reference is an object and a valid object.
The same can't be said of a pointer, or any pointer.

Let's make the following assumption: every type is implicitly derived
from void. Many C++ programmers can accept that.

Name one. It's manifestly false; it is, in fact, illegal to
derive from void (or from any incomplete type).

Void, as a type, is an incomplete type, which can never be
completed. And in no case can you derive from an incomplete
type. The rules concerning convertion of T* to void* do NOT
obey the rules of derived to base (which only works if the types
are complete), and of course, work even in cases where
inheritance would be illegal, e.g. int* to void*.

James Kanze (GABI Software)
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