On 31 January 2010 20:34, Maarten Lankhorst <m.b.lankhorst at gmail.com> wrote: > + STDMETHOD_(HRESULT,QueryInterface)(THIS_ REFIID riid, void** ppvObject) Looking at some other headers this seems a common thing to do, but is there really a reason to use STDMETHOD_(HRESULT,QueryInterface) over just STDMETHOD(QueryInterface)?