Does an abstract classes have a VTABLE?

Question

Do we have virtual table for an abstract class?

Answer 1

There seems to be a common misconception here, and I think traces of its sources can still be found online. Paul DiLascia wrote sometime in 2000 that -

...see that the compiler still generates a vtable all of whose entries are NULL and still generates code to initialize the vtable in the constructor or destructor for A.

That may actually have been true then, but certainly isn't now.

Yes, abstract classes do have vtables, also with pure abstract methods (these can actually be implemented and called), and yes - their constructor does initialize the pure entries to a specified value. For VC++ at least, that value is in the address of the CRT function _purecall. You can in fact control that value, either by overloading purecall yourself or using _set_purecall_handler.