c++ - difference between interface inheritance and implementation inheritance

Question

I found those two terms in the book of Meyers, but what is the difference?

Answer 1

Interface inheritance is public inheritance, while implementation inheritance is private inheritance.

If class B publicly inherits from A, B is an A: it inherits the whole interface of A, and a (reference/pointer to) a B object can be automatically be upcasted to A, and used wherever an object of A is expected. However, if B privately inherits from A, B is-implemented-in-terms-of A: only the implementation of A is inherited, not its interface. Thus (references/pointers to) B objects can not be used in places where A objects are expected.

Update

To reflect on @Michal's comment, here are some links (based largely on googling "c++ implementation inheritance") to demonstrate the common usage of these terms in the context of C++:

• C++ Design/Coding tips - Part 7
• Interfaces
• Uses and Abuses of Inheritance, Part 1