C++ Q on types

[Andrew Cagney]

Via RMS:
> A user (haberg@matematik.su.se) sent me this explanation of a feature
> in some other debuggers:
> 
>     C++ has makes available various runtime information (RTTI). C++ has a
>     single one form of a polymorphic variable, or an object which can change
>     its type at runtime, namely the polymorphic pointer: If one has a class A
>     and derives from it a class B, then one can write
>       A* ap = new B();
>     The static type pointer to an  A  named  ap  now points to a dynamically
>     allocated  B  pointer. It means that in the C++ static typing, this is just
>     an  ap  pointer, but C++ has mechanism for keeping track of the dynamic
>     type  B, for example, via "virtual functions", or by using C++ RTTI...
> 
>     Now to the debugging: If the debugger only handles C++ static typing, it
>     will show that  ap  is an  A, and will only display that structure of it
>     (the names in that class and their values).
> 
>     But if the debugger handles C++ dynamic data, it will show that the  ap  is
>     actually a  B, and will show that (the names in that class  B  and their
>     values).
> 
> Does GDB have the ability to determine the actual type
> of *ap, and display it accordingly?

Something for TODO?