title: What does the "&" sign mean in PHP?
body: <p>I was trying to find this answer on Google, but I guess the symbol <code>&amp;</code> works as some operator, or is just not generally a searchable term for any reason.. anyhow. I saw this code snippet while learning how to create WordPress plugins, so I just need to know what the <code>&amp;</code> means when it precedes a variable that holds a class object.</p>
  
  <pre><code>//Actions and Filters
  if (isset($dl_pluginSeries)) {
  
      //Actions
      add_action('wp_head', array(&amp;$dl_pluginSeries, 'addHeaderCode'), 1);
      //Filters
      add_filter('the_content', array(&amp;$dl_pluginSeries, 'addContent'));
  }
  </code></pre>