class A
{
    var $hello;
    var $world;

    function A()
    {
        $this->hello = "hello";
    }
}

$a = get_class_vars("A");
foreach ($a as $key => $val)
{
    echo $key . ": " . $val . "<br>";
}

Output does not show the value as it suggests in the documentation. The output I get is:

hello: 
world: 

Notice that the value of $hello is not shown.
Docs say uninitialized variables are not shown. But clearly hello is initialized.

Calling this:
   $a = get_class_vars("A");
   print_r($a);

Produces:
   Array ( [hello] => [world] => ) 

Which also is wrong because of no values in hello