An optional dynamic-link library that developers can provide to notify their desktop applications about synchronization activities. HotSync Manager calls all registered notifiers before synchronization begins, passing them a message that they act upon - for example, telling the desktop application to save and stop modifying data. Notifiers are called again after synchronization so they can in turn tell their desktop applications whether the synchronization completed successfully. The API you must implement for a notifier is specified in the C/C++ Sync Suite.