J = I + use ATL macros and templates including full self registration

**** .idl ****

interface IXxxx : IDispatch

library XxxxLibrary
    coclass CoXxxx

**** .h ****

class CCoTest : CComObjectRootEx<CComSingleThreadModel>, CComCoClass<CCoXxxx, CLSID_CoXxxx>, IDispatchImpl<IXxxx, IID_IXxxx, LIBID_XxxxLibrary>

**** registry ****

auto via DllRegisterServer and DllUnegisterServer in DLL

**** C++ usage ****

import tlb

IXxxxPtr p
IXxxxPtr.CreateInstance()

or:

IXxxxPtr p()

**** C# usage ****

CoXxxx co = new CoXxxxClass()
IXxxx o = (IXxxx)co

**** dynamic C# usage ****

dynamic o = Activator.CreateInstance()

**** VBS usage ****

Set o = CreateObject()