title: How to set a unique message for a rule on multiple inputs in CodeIgniter?
body: <p>My view contains a form with 3 similar inputs:</p>
  
  <pre><code>&lt;input type="text" name="email1" /&gt;
  &lt;input type="text" name="email2" /&gt;
  &lt;input type="text" name="email3" /&gt;
  </code></pre>
  
  <p>I added a callback to control that each textbox does not get the current session email.</p>
  
  <pre><code>public function check_session_email($email){
      if($this-&gt;session){
          if ($this-&gt;session-&gt;userdata('email') != $email){
              return TRUE;
          }else{
              $this-&gt;form_validation-&gt;set_message('check_session_email', 'You can't include your own email address.');
              return FALSE;
          }
      }
  }
  </code></pre>
  
  <p>If I used the current session email, the error message displays twice (same thing with three).</p>
  
  <p><img src="https://i.stack.imgur.com/G6cAz.jpg" alt="enter image description here"></p>
  
  <p>Of course, that sounds logical ...but not very user-friendly. So my question is : how to include only one error message for a rule?</p>