<?php
$a = 3;
$b = &$a;
echo 'B = '.$b."\n";
$b = 2;
echo 'A = '.$a."\n";
$a = 5;
echo 'B = '.$b."\n";

function links(&$var){
  $var = 1;
  global $a;
  $a = 3;
  echo 'GLOBAL A = '.$a."\n";
  echo 'VAR = '.$var."\n";
  return $var+1;
}

$a = links($a);
echo 'B = '.$b."\n";
echo 'A = '.$a."\n";