Microsoft ActiveSync synchronization overview

Synchronization through Microsoft ActiveSync can be summarized in a few steps.

1. Microsoft ActiveSync begins a synchronization session.

2. The Microsoft ActiveSync provider sends a synchronize notification message to the first registered application on the device. The application is started if it is not yet running.

3. WndProc is invoked for each registered application.

4. Once the application has determined that this is the synchronize notification message from Microsoft ActiveSync, the application calls ULIsSynchronizeMessage to invoke the database synchronization procedure.

5. Once synchronization is complete, the application calls ULSignalSyncIsComplete to let the provider know that it has finished synchronizing.

6. Steps two-five are repeated for each application that has been registered with the provider.