Pure virtual functions may not have an inline definition. Why?

Question

Pure virtual functions are those member functions that are virtual and have the pure-specifier ( = 0; )

Clause 10.4 paragraph 2

Answer 1

Good guesses are welcome you say?

I think the = 0 at the declaration comes from having the implementation in mind. Most likely this definition means, that you get a NULL entry in the RTTI's vtbl of the class information -- the location where at runtime addresses of the member functions of a class are stored.

But actually, when put a definition of the function in your *.cpp file, you introduce a name into the object file for the linker: An address in the *.o file where to find a specific function.

The basic linker then does need to know about C++ anymore. It can just link together, even though you declared it as = 0.

I think I read that it is possible what you described, although I forgot the behaviour :-)...