| Data member | Description |
| m_critsec | A CComAutoCriticalSection object or CComFakeCriticalSection object, depending on the thread model. |
| m_dwRef | Part of a union with m_pOuterUnknown. Used when the object is not aggregated to hold the reference count. |
| m_pOuterUnknown | Part of a union with m_dwRef. Used when the object is aggregated to hold a pointer to the outer IUnknown. |