How am i supposed to access and change a variable over different controllers ?

Hello , im trying to solve my mysterious    problem with codeigniter !

I want to pass a value from one controller's function to another controller's function and edit it's value.

This is what i have

Code:

class MY_Controller extends Controller { }
class MY_User extends MY_Controller {}

and

class Liveshow extends MY_Controller {
    function a() {
        //set a global $test = 123;
    }
}

class Channels extends MY_User {
    function b() {
        //echo the global variable $test
    }
}

How am i supposed to make it work ?  

Thanks !

Although you can't pass a value from one Controller to another you can process the method in a model and return the result. Then access it from any controller you need to.

If you mean to have a variable from MY_Controller and assign a value from any controller that extends MY_Controller you can do this:

PHP Code:

class MY_Controller extends CI_Controller {

  public $data = array();

    function __construct()
    {
      parent::__construct();
    }

  public function load_view($subview, $your_variable= '' // could be an array here)
  {
      // $this->data allows to pass any array value to the view
      // like errors or values.
      $this->data['your_variable_here'] = $your_variable;

      $this->data['subview'] = $subview;
      $this->load->view('layouts/layout', $this->data);
  }
} 


I use the $subview variable to pass the view of a controller using a layout.