The form of a constant, type, or exception declaration within the body of an interface declaration is the same as described previously in this chapter. Constants and types defined within an interface for a class are transferred by the SOM Compiler to the binding files it generates for that class, whereas constants and types defined outside of an interface are not.
Global types (such as, those defined outside of an interface and module) can be emitted by surrounding them with the following #pragmas:
#pragma somemittypes on
typedef sequence <long,10> vec10;
exception BAD_FLAG { long ErrCode; char Reason[80]; };
typedef long long_t;
#pragma somemittypes off
Types, constants, and exceptions defined in a parent class are also accessible to the child class. References to them, however, must be unambiguous. Potential ambiguities can be resolved by prefacing a name with the name of the class that defines it, separated by the characters "::" as illustrated below:
MyParentClass::myType
The child class can redefine any of the type, constant, and exception names that have been inherited, although this is not advised. The derived class cannot, however, redefine attributes or methods. It can only replace the implementation of methods through overriding (as in example 3 of the Tutorial). To refer to a constant, type, or exception "name" defined by a parent class and redefined by "class-name," use the "parent-name::name" syntax as before.
Note: A name reference such as MyParentClass::myType required in IDL syntax is equivalent to MyParentClass_myType in C/C++. For a full discussion of name recognition in SOM, see "Scoping and name resolution" later in this chapter.