typedef struct IUnknownVtbl
{
    BEGIN_INTERFACE

    HRESULT ( STDMETHODCALLTYPE *QueryInterface )(
        IUnknown * This,
        /* [in] */ REFIID riid,
        /* [annotation][iid_is][out] */
        __RPC__deref_out  void **ppvObject);

    ULONG ( STDMETHODCALLTYPE *AddRef )(
        IUnknown * This);

    ULONG ( STDMETHODCALLTYPE *Release )(
        IUnknown * This);

    END_INTERFACE
} IUnknownVtbl;