Fun with extern(C++)

[Walter Bright via Digitalmars-d]

To understand this you have to step back and understand what interfaces actually 
are.

They have one member, and that member is a pointer to its vtbl[]. The vtbl[] is 
populated with pointers to functions.

That is it.

There is no runtime type info there.

Interfaces are how different languages communicate with each other - Java, D, 
C++, Basic, etc., support this. This is one reason why there is no RTTI there. 
An interface is supposed to stand on its own.

So yes, D and C++ can communicate via interfaces.