title: Does function definition order matter?
body: <p>In the script below, does the order in which items are declared matter?</p>
  
  <p>For example, if the add_action points to a function that has not yet been defined? Does it matter or should the function declaration always precede any code in which its called?</p>
  
  <pre><code>add_action('load-categories.php', 'my_admin_init');
  function my_admin_init(){
  //do something
  }
  </code></pre>