This might be obvious to many, but just to help others that are trying to use this in a class. Inside a class, you can prefix the function with self:: within the uksort(), and it will work. Also, if it is in another class that is included, you can prefix it with the class name.
class someclass {
private function ArraySortCMPIP($a, $b) {
$a = ip2long($a);
$b = ip2long($b);
if ($a == $b) return 0;
return ($a < $b) ? -1 : 1;
}
// Output
public function PrintResults() {
uksort($this->someIPAddressArray, 'self::ArraySortCMPIP');
print_r($this->someIPAddressArray);
}
}