title: How long can an iPhone app live in the background?
body: <p>I can't seem to find a clear answer to this-- I'm spec'ing out an iPhone app that I'd like to have live in the background and notify the user at certain periods throughout the day. So the user would launch the app in the morning and then continue to use their phone, then every few hours the app would pop open a notification dialog.</p>
  
  <p>Will my app ever be shut down (automatically) by the OS? Or will it just live forever, notifying user when it needs to?</p>
  
  <p>thanks,
  Eric</p>