In the Networking package, a socket address type is represented by an RWSockType object. This is a concrete class that does not have virtual functions, but does have copying and assignment semantics. The RWInetType class can be used to construct an RWSockType for the Internet family of classes. Because RWSockType is a concrete class, these derived classes can be converted to instances of RWSockType with no change in the semantics of the object.