title: stringByAppendingFormat not working
body: <p>I have an NSString and fail to apply the following statement:</p>
  
  <pre><code>NSString *myString = @"some text";
  [myString stringByAppendingFormat:@"some text = %d", 3];
  </code></pre>
  
  <p>no log or error, the string just doesn't get changed. I already tried with NSString (as documented) and NSMutableString.</p>
  
  <p>any clues most welcome.</p>