PHP 4 OO wasn't - Objects were base types.

You needed to explicitly pass objects by reference.

You even needed to instantiate them by reference.

<?php
class Brand {
    var $name;
}

function change_name(&$drinkobj, $name)
{
    $drinkobj->name = $name;
}

// avoid double copy
$drink = &new Brand;
$drink->name = 'Coke';
var_dump($drink->name);
change_name($drink, 'Pepsi');
echo "{$drink->name} the choice of a new generation\n";
?>