An integer_type_spec is a type_specifier for an integer, except that the int_size for an integer constant cannot be hyper.
An integer is the decimal representation of an integer. IDL also supports the C notation for hexadecimal, octal, and long integer constants.
You can specify any previously defined integer constant as the value of an integer constant.
You can specify any arithmetic expression as the integer_const_expression that evaluates to an integer constant.