Attributes allow you to associate a value with an interface. IDL attributes are similar in concept to structure fields in languages such as C. However, when mapped to a programming language, attribute values can typically be accessed only by generated functions that allow you to set and retrieve the attribute’s value.
Attributes are declared as shown below:
[ readonly ] attribute TypeSpec name;
where
readonly is an optional keyword specifying that the attribute can be retrieved but cannot be set.
TypeSpec is the name of a standard or user-defined type. “Datatypes for parameters and return values” describes datatypes in detail.
name is the attribute name.
In C++ and Java, a read-only attribute maps to a method with the same name that returns the attribute type. A writable attribute maps to a pair of overloaded methods with the same name as the attribute. For example, consider the following IDL declarations:
readonly attribute long days; // readonly attribute long months; // writable
In a C++ or Java implementation of the interface, these methods must be declared:
long days(); long months(); void months(long new_months);
