The first step in defining the interface is to use the uuidgen utility to generate a universally unique identifier (UUID) that lets the client and server applications recognize each other.
The uuidgen utility (UUIDGEN.EXE) is automatically installed when you install the Win32 SDK. The following command generates a UUID and creates a template file called hello.idl:
C:\>uuidgen /i /ohello.idl
Your hello.idl template will look like this (with a different UUID, of course):
[
uuid(7a98c250-6808-11cf-b73b-00aa00b677a7),
version(1.0)
]
interface INTERFACENAME
{
}