title: Codeigniter passing 2 arguments to callback
body: <p>After posting a form having two fields named 'id' and 'url' I have the following code:</p>
  
  <pre><code>$this-&gt;load-&gt;library('form_validation');
  $this-&gt;form_validation-&gt;set_rules('id', 'id', 'trim|xss_clean');
  $this-&gt;form_validation-&gt;set_rules('url', 'url|id', 'trim|xss_clean|callback_url_check');
  </code></pre>
  
  <p>A db query needs both fields.</p>
  
  <p>The function url_check($str, $id) is called but in this case 'id' always has the value 0.</p>
  
  <p>If I just do :</p>
  
  <pre><code>$this-&gt;form_validation-&gt;set_rules('url', 'url', 'trim|xss_clean|callback_url_check');
  </code></pre>
  
  <p>And call <code>url_check($str)</code> everything's working as it's is supposed to do.</p>
  
  <p>The question is how do I pass two values to the <code>url_check($str, $id)</code>?</p>