If it is unresolved within the scope, it is searched for in outer scopes. Interfaces are the main component in IDL specifications. They group attributes and operations. Interfaces are composed of a head and a body. The header specifies the header and any inheritance structure.
Interfaces can inherit declarations from base interfaces.
Multiple interface inheritance is supported. Ambiguities are resolved by qualifying identifiers. If an attribute is declared as read-only, no set function is defined. Exception declarations take the form of structure definitions. They have identifier and member definitions.