A custom class rarely overrides these functions:
virtual AcRxObject*
clone() const;
virtual Acad::ErrorStatus
copyFrom(const AcRxObject* pSrc);
// Do not override; AcDbObject behavior is already accounted for.
//
virtual HRESULT __stdcall
QueryInterface ( REFIID riid,
void ** ppvObject );
virtual ULONG __stdcall
AddRef();
virtual ULONG __stdcall
Release();