(ref.doc)cr5/6-corba

pp 32-38
Distributed object computing with CORBA
by Steve Vinoski (Note: Vinoski)

The OMG was formed with the purpose of creating standards allowing for
the interoperability and portability of distributed object-oriented
applications.

In C++ terms, IDL interface inheritance exhibits the following
characteristics:

- All base interfaces are effectively public virtual
- All operations are effectively virtual
- Operations cannot be redeclared in derived interfaces
- There is no notion of implementation inheritance

There is no concept of state in IDL, only behavior.

IDL interfaces are mapped to C++ classes called *surrogates*, and IDL
operations are mapped to member functions of those surrogates.

Not only do object surrogate classes provide a natural mapping for IDL
to C++, they also maintain the compile-time type checking that C++
users rely on.