After you have used uuidgen to generate a skeletal interface definition, replace the dummy string INTERFACENAME with the name of your interface.
By convention, the name of an interface definition file is the same as the name of the interface it defines, with the suffix .idl appended. For example, the definition for a bank interface would reside in a bank.idl interface definition file, and, if the application required an ACF, its name would be bank.acf.
The IDL compiler incorporates the interface name in identifiers it constructs for various data structures and data types in the .h file, so the length of an interface name can be at most 17 characters. (Most IDL identifiers have a maximum length of 31 characters.)