ObjectARX applications must implement a document manager reactor to receive notification about document status changes if any of the following conditions apply:
- They need to manage per-document state.
- They need to be notified whenever a document or its database(s) are going to be modified, or are done being modified.
- They need to keep track of document switches, that is, which document is being made current or active.
The AcApDocManagerReactor makes callbacks when changes in document status take place, such as opening, closing, activation, deactivation, and changing the lock status of documents.