title: Passing function as argument to Objective-C method
body: <p>I'd like to pass a <code>C</code> function as an argument to an Objective-C method, to then act as a callback. The function has type <code>int (*callback)(void *arg1, int arg2, char **arg3, char **arg4)</code>.</p>
  
  <p>I keep getting the syntax wrong. How do I do this?</p>