13.1.21 Interfaces

An interface in OMG IDL is mapped to a C++ class. This class contains the definitions of the operations, attributes, constants, and user-defined types (UDTs) contained in the OMG IDL interface.

For an interface INTF, the generated interface code contains the following items:

• Object reference type (INTF _ptr)
• Object reference variable type (INTF _var)
• _duplicate static member function
• _narrow static member function
• _nil static member function
• UDTs
• Member functions for attributes and operations

For example, consider the following OMG IDL definition:

// OMG IDL
module INVENT
    {
     interface Order
      {
      void cancelOrder ();
      };
};

This definition maps to C++ as follows:

// C++
class INVENT
    {
      . . .
      class   Order;
      typedef Order *             Order_ptr;
    class Order : public virtual CORBA::Object
       {
       . . .
       static Order_ptr _duplicate(Order_ptr obj);
       static Order_ptr _narrow(CORBA::Object_ptr obj);
       static Order_ptr _nil();
       virtual void cancelOrder () = 0;
      . . .
      };
};

The object reference types and static member functions are described in the following sections, as are UDTs, operations, and attributes.