The following classes implement IUnknown and related methods:

• CComObjectRootEx Manages reference counting for both aggregated and nonaggregated objects. Allows you to specify a threading model.

• CComObjectRoot Manages reference counting for both aggregated and nonaggregated objects. Uses the default threading model of the server.

• CComAggObject Implements IUnknown for an aggregated object.

• CComObject Implements IUnknown for a nonaggregated object.

• CComPolyObject Implements IUnknown for aggregated and nonaggregated objects. Using CComPolyObject avoids having both CComAggObject and CComObject in your module. A single CComPolyObject object handles both aggregated and nonaggregated cases.

• CComObjectNoLock Implements IUnknown for a nonaggregated object, without modifying the module lock count.

• CComTearOffObject Implements IUnknown for a tear-off interface.

• CComCachedTearOffObject Implements IUnknown for a "cached" tear-off interface.

• CComContainedObject Implements IUnknown for the inner object of an aggregation or a tear-off interface.

• CComObjectGlobal Manages a reference count on the module to ensure your object won't be deleted.

• CComObjectStack Creates a temporary COM object, using a skeletal implementation of IUnknown.

Fundamentals of ATL COM Objects

Class Overview
Aggregation and Class Factory Macros
COM Map Macros
COM Map Global Functions