debug_zval_dump

Dumps a string representation of an internal zend value to output (PHP 4 >= 4.2.0, PHP 5)
void debug_zval_dump ( mixed variable )

<?php

$var1 = 'Hello World';
$var2 = '';

$var2 =& $var1;

debug_zval_dump(&$var1);
?>

The above example will output:

string(11) "Hello World" refcount(3)

<?php

$var1 = 'Hello World';
$var2 = '';

$var2 =& $var1;

debug_zval_dump($var1); // not passed by reference, this time
?>

The above example will output:

string(11) "Hello World" refcount(1)

<?php

$var1 = 'Hello World';

debug_zval_dump($var1);
?>

The above example will output:

string(11) "Hello World" refcount(2)

ilpochta

First link [Reference Counting and Aliasing (by Andi Gutmans)] not work, see it in web-archive http://tinyurl.com/ytvrjt