Public variable in controller

[eluser]someone [/eluser]
Hello!

I've created some controller with public variable, which I would like to use in all functions. It looks like this:

Code:

<?php
class Test extends CI_Controller {

public $appname = "test";

public function index()
{
  echo $this->appname . " is name of app.";
}
}
?>

Is this way of using variable secure and true or is any other way better?

Thanks! :-)