Class function calling another class as global (wrong scope?)

Hi guys,

I am trying to call a class function from another class function but when calling global $hcdb; it loads as NULL. I read some time ago about having to declare it as a global but think it was only for variables. Any ideas? Sounds like quite a basic thing…

Stripped code of the files below:

main.php (the one that loads first)

require_once(HC_PATH_INTERNAL."/includes/database.php");
require_once(HC_PATH_INTERNAL."/includes/functions.php");

$hc->format();

database.php

class HcDatabase {
  function checknicename() { return 1; }
}
$hcdb = new HcDatabase;

functions.php

class HcFunctions {
  function format() {
    global $hcdb;
    var_dump($hcdb); // returns NULL
    $hcdb->checknicename();
  }
}
$hc = new HcFunctions;