title: Understanding NSRunLoop
body: <p>Can anyone explain for what is <code>NSRunLoop</code>? so as I know <code>NSRunLoop</code> is a something connected with <code>NSThread</code> right? So assume I create a Thread like </p>
  
  <pre><code>NSThread* th=[[NSThread alloc] initWithTarget:self selector:@selector(someMethod) object:nil];
  [th start];
  
  -(void) someMethod
  {
      NSLog(@"operation");
  }
  </code></pre>
  
  <p>so after this Thread finishes his working right? why use <code>RunLoops</code> or where to use ?  from Apple docs I have read something but its not clear for me, so please explain as simple as it possible</p>