It serves as the root not only for library classes such as CFile and CObList, but also for the classes that you write. CObject provides basic services, including
Note that CObject does not support multiple inheritance. Your derived classes can have only one CObject base class, and that CObject must be leftmost in the hierarchy. It is permissible, however, to have structures and non-CObject-derived classes in right-hand multiple-inheritance branches.
You will realize major benefits from CObject derivation if you use some of the optional macros in your class implementation and declarations.
The first-level macros, DECLARE_DYNAMIC and IMPLEMENT_DYNAMIC, permit run-time access to the class name and its position in the hierarchy. This, in turn, allows meaningful diagnostic dumping.
The second-level macros, DECLARE_SERIAL and IMPLEMENT_SERIAL, include all the functionality of the first-level macros, and they enable an object to be "serialized" to and from an "archive."
For information about deriving Microsoft Foundation classes and C++ classes in general and using CObject, see Using CObject and Serialization.