[
   object,
   uuid(ba63909b0-bc3b-11d0-ab58-0000c0b8f396),
   helpstring("A basic MIDL interface"),
   pointer_default(unique)
]
interface IFoo : IUnknown
{
   import "unknwn.idl";
   HRESULT bar([in] long aNumber,
               [out, string] wchar_t *outParam);
}