title: What does having two asterisk ** in Objective-C mean?
body: <p>I understand having one asterisk * is a pointer, what does having two ** mean?</p>
  
  <p>I stumble upon this from the documentation:</p>
  
  <pre><code>- (NSAppleEventDescriptor *)executeAndReturnError:(NSDictionary **)errorInfo
  </code></pre>