title: Use CodeIgniter's base url inside a different config file
body: <p>I'm trying to get another framework working inside of CodeIgniter and this other framework has it's own config file.  One of the values it needs is the site or base url.  I thought I'd simply use CI's base url value from the application/config/config.php file.  I've tried two methods:</p>
  
  <ol>
  <li>Simply use <code>base_url()</code>.  The url helper is being autoloaded.  This produces "Fatal error: Call to undefined function base_url()"</li>
  <li>Do a <code>require_once APPPATH . 'config/config.php';</code>, then use <code>$config['base_url']</code>.  This method works for using application/config/database.php's database values.  But for the base url, I get this error: "Message: Undefined variable: config".  I don't understand why it works for database.php but not config.php.  </li>
  </ol>
  
  <p>What is the correct way to do this?</p>