determining if a void* points to a valid Object

[Luís Marques]

nobody wrote:
> I think if I understand your question correctly then I believe what you 
> can do if first assert( ptr !is null ). Now if I can define NotDObject 
> and initialize the members I would do the following:
> 
> 
>   struct NotDObject
>   {
>     int reserveredA = 0;
>     int reserveredB = 0;
>     // anything you want follows here
>   }
> 
> Now since we know ptr is not null then it it points to a NotDObject then 
> dereferencing the pointer should give us a null value. Otherwise we now 
> have a pointer to the vtable from the D ABI above.
> 
>   if((*(cast(void*)) is null ) // NotDObject
>   else                         // Object

Yes, that's exactly what I need (thanks).

But 1) I guess reserveredB is unnecessary, no? 2) see my previous 
question: 'can a D Object not have a vtable? That is, could the "pointer 
to vtable" be null?' (what happens? it points to a 0 entry table?)

Luís