How to prevent derived class from making a private/protected virtual function public?

Question

There are good reasons for constructing the base class interface with all virtual functions as private or protected (see this). But then how does one prevent the derived cla

Answer 1

Promoting a private/protected virtual method to public in a derived class does not expose the base class method. It still cannot be called through a base class pointer. It does not become part of the interface of the base clase.