In my application I need to keep track of when the user last interacted with my application. If there has been no interaction for a certain period of time the application will automatically exit itself.

One of the things that comes to mind is that the screen saver starts to run after a certain period of inactivity. So I assume there may be an API(s) I can call which tells me gives me information as to when the last time a user interacted with a particular application... or something on similar lines.

Any help/input/ideas will be appreciated.
Thanks,
Ashish