title: Setting Session_id in CodeIgniter
body: <p>In standard PHP i can set the session ID by following:</p>
  
  <pre><code>$my_session_id = $_GET['session_id']; //gets the session ID successfully
  session_id($my_session_id);   //sets the session with my session_id
  session_start();  //starts session.
  </code></pre>
  
  <p>How can I do same with the CodeIgniter? I am trying following:</p>
  
  <pre><code>$my_session_id = $_GET['session_id']; //gets the session ID successfully
  $this-&gt;session-&gt;userdata('session_id', $my_session_id); //it won't set the session with my id.
  print_r($this-&gt;session-&gt;userdata);
  </code></pre>
  
  <p>Am i making some mistake? Please help me as I have wasted several hours in this problem. If there is some issue with CodeIgniter Session class, can I use the standard PHP code to start session? I have tried to place the standard code in CodeIgniter as well, but it still does not set the session_id. I have also set <code>$config['sess_match_useragent']    = FALSE;</code></p>