title: CI3/ Validation Rules to a Config File & Using a callback
body: <p>I am unable to figure out where to place my callback when using validation rules to a config file in CI3.  Here is my form_validation.php:</p>
  
  <pre><code> &lt;?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
  
   $config = array(
     'blog_post' =&gt; array(
  
        array(
          'field' =&gt; 'entry_name', 
          'label' =&gt; 'entry_name', 
          'rules' =&gt; 'min_length[8]|trim|required|max_length[255]'
          ),
  
        array(
          'field' =&gt; 'entry_body', 
          'label' =&gt; 'entry_body', 
          'rules' =&gt; 'trim|required|min_length[12]|callback_html_length_without_html'
          ),
      ),
  );
  
  function html_length_without_html(){
     if (2 &lt; 1)
      {
          $this-&gt;form_validation-&gt;set_message('html_length_without_html', 'The field can not be the word');
          return FALSE;
      } else {
          return TRUE;
      }
  }
  </code></pre>
  
  <p>However, when I run the above, I get the following error:</p>
  
  <pre><code> Unable to access an error message corresponding 
   to your field name entry_body.(html_length_without_html)
  </code></pre>
  
  <p>Where do I place the callback "html_length_without_html()"?</p>