title: session_destroy() in codeigniter
body: <p>How come destroy_session() method doesn't work.</p>
  
  <p>After set_session(), destroy_session(), I still can read_session().</p>
  
  <pre><code>function set_session() {
      $this-&gt;load-&gt;library('session');
      $this-&gt;session-&gt;set_userdata('id', 4);
  }
  
  function destroy_session() {
      session_start(); 
      session_destroy();
      unset($_SESSION);
      session_regenerate_id(true);
  }
  
  function read_session() {
      $this-&gt;load-&gt;library('session');
  
      $id = $this-&gt;session-&gt;userdata('id');
  
      echo $id;
  }
  </code></pre>