CComContainedObject< contained > m_contained;
Parameters
contained
[in] Your class, derived from CComObjectRoot or CComObjectRootEx, as well as from any other interfaces you want to support on the object.
Remarks
A CComContainedObject object derived from your class. IUnknown calls through m_contained are delegated to the outer unknown if the object is aggregated, or to the IUnknown of this object if the object is not aggregated.