title: How to cancel a previously scheduled event in Objective-C?
body: <p>I am making an iphone app and have scheduled an event called gameOver to occur after 15 seconds(when the game is over).</p>
  
  <pre><code>[self performSelector:@selector(gameOver) withObject:nil afterDelay:15.0];
  </code></pre>
  
  <p>How can I unschedule this event so that if someone wanted to press a reset button and start the game over, this scheduled event would be deleted and another one would be created.</p>