title: can't use session at codeIgniter
body: <p>I have a session in my form controller the session is create when the user save 
  the session affect the form page so my problem is :</p>
  
  <p>if I loaded the page without clicking on save a undefined index[session index] error appears </p>
  
  <p>so I created the session at the home page
  but the problem is if I loaded the form page without visiting the home page at first the undefined index error appear
  I tried to call the method <code>session_start()</code> but I got this error
  A PHP Error was encountered</p>
  
  <blockquote>
    <p>Severity: Notice Message: A session had already been started -
    ignoring session_start() Filename: views/Form.php Line Number: 5</p>
  </blockquote>