The keyword boolean indicates that the expression or constant expression associated with the identifier takes only the values TRUE and FALSE.
Specifies a valid MIDL identifier. Valid MIDL identifiers consist of up to 31 alphanumeric and/or underscore characters and must start with an alphabetic or underscore character.
The boolean type is one of the base types of the IDL language. The boolean type can appear as a type specifier in const declarations, typedef declarations, general declarations, and function declarators (as a function-return-type specifier and as a parameter-type specifier). For the context in which type specifiers appear, see Interface Definition (IDL) File.
The boolean base type is not compatible with the oleautomation attribute. Use VARIANT_BOOL in your Automation-compatible interfaces.