title: Warning: Unimplemented Selector localizedCaseInsensitiveCompare
body: <p>I'm getting the subject warning on the following line: </p>
  
  <pre><code>   NSSortDescriptor * sort = [ [NSSortDescriptor alloc] initWithKey:@"name"
                                   ascending:YES
                                    selector:@selector(localizedCaseInsensitiveCompare:) ];
  </code></pre>
  
  <p>And I didn't always get that warning.  That is, the warning just started to appear recently, possibly due to a change in compilation settings.  I don't see a typo, here.  This looks (to me) just like code I've seen in many examples.  I'm not seeing a run time exception.  But I don't like warnings.  Anyone seen this?  Any idea what's triggering it?</p>