ATL Internals: Working with ATL 8, Second Edition

Chapter 7. Persistence in ATL

A Review of COM Persistence

Objects that have a persistent state should implement at least one persistence interface—and, preferably multiple interfaces—to provide the container with the most flexible choice of how it wants to save the object’s state. Persistent state refers to data (typically properties and instance variables) that an object needs to have preserved before a container destroys the object. The container provides the saved state to the object after it re-creates the object so that the object can reinitialize itself to its previous state.

COM itself doesn’t require an object to support persistence, nor does COM use such support if it’s present in an object. COM simply documents a protocol by which clients ...