$GLOBALS example script on php.net

[Ashim Kapoor <ashimkapoor@xxxxxxxxx>]

Dear all,

I was reading this page
http://php.net/manual/en/reserved.variables.globals.php and  I found the
following script there : ----


Here's a function which returns an array of all user defined global
variables:

<?php
function globals() {
    $globals = $GLOBALS;
    foreach (array(
        'GLOBALS',
        '_ENV',
        'HTTP_ENV_VARS',
        '_POST',
        'HTTP_POST_VARS',
        '_GET',
        'HTTP_GET_VARS',
        '_COOKIE',
        'HTTP_COOKIE_VARS',
        '_SERVER',
        'HTTP_SERVER_VARS',
        '_FILES',
        'HTTP_POST_FILES',
        '_REQUEST'
    ) as $var) {
        unset($globals[$var]);
    }

    return $globals;
}
?>

I think that this script UNSETS each supergobal variable,but page says that
it returns ALL user defined vars ? Can some one tell me how that is ?

Thank you,
Ashim