What does =& mean in PHP?

Question

Consider:

$smarty =& SESmarty::getInstance();

What is the & for?

Answer 1

In PHP 4, it kind of (awkwardly) associated two variables.

$j = 'original';
$i =& $j;
$i = 'modified';
echo $j; // The output is 'modified'

Likewise...

$j = 'original';
$i =& $j;
$j = 'modified';
echo $i; // The output is 'modified'

Some of this was made a little less unpleasant when it comes to objects in PHP 5, but I think the heart of it is the same, so these examples should still be valid.