Use Events

Events are notifications, or messages, that are sent out by AutoCAD® to inform you about the current state of the session, or alert you that something has happened. For example, when a drawing is saved the BeginSave event is triggered. There are other events triggered when a drawing is closed, a command is started or even when a system variable is changed. Given this information you could write a subroutine, or event handler, that uses these events to track changes to a drawing or the amount of time a user spends working on a particular drawing.