$ref1 = $obj1; // $ref1 is a link to obj1

If we follow the manual strictly, we’ll see that both $ref1 and $obj1 are links to the same content. After  $ref2 = $ref1 another link to the same content should be added.

Thus after $ref1 = $obj2 all three links should indicate to $obj2.

In the manual it is written that links in PHP are different from indicators in C. At this there is no such type as ‘link’ in PHP and so it’s impossible to check what $ref2 is.

Generally basing on the work of the template we may say that PHP differentiates links types.

Now I’ll try to formulate more precisely what exactly embarrasses me.

<?php 
class Simple 
{ 
    public $name; 
} 

$obj1 = new Simple(); 
$obj1->name = 'obj1'; 

$obj2 = new Simple(); 
$obj2->name = 'obj2'; 

$ref1 = $obj1; 

$ref1 = $obj2; 

print 'name: '.$obj1->name; // "name: obj1" 
?>

As it is known objects in PHP5 are transmitted via link i.e. string $ref1 = $obj1 is equal to $ref1 =& $obj1. We’ll try to replace this string:

<?php 
$ref1 =& $obj1; 

$ref1 = $obj2; 

print 'name: '.$obj1->name; // in this case "name: obj2" 
?>

Strings $ref1 = $obj1 and $ref1 =& $obj1 turn out not to be equal.

We’ll try to change the following string:

<?php 
$ref1 =& $obj1; 

$ref1 =& $obj2; 

print 'name: '.$obj1->name; // in this case "name: obj1" 
?>

It is quite logical because it has to be so.

Generally speaking in case with objects links act according to some other rules which are not described in the manual or maybe I have missed something…

OK, I’ve found. It has been already discussed here http://www.php.net/manual/en/language.oop5.basic.php

In the unit ‘new’

<?php 
$assigned  =  $instance; 
$reference =& $instance; 

$instance->var = '$assigned will have this value'; 

$instance = null; // $instance and $reference become null 

var_dump($instance); 
var_dump($reference); 
var_dump($assigned); 
?>

The above example will output:

NULL 
NULL 
object(SimpleClass)#1 (1) { 
   ["var"]=> 
     string(30) "$assigned will have this value" 
}

Also
http://www.php.net/manual/en/language.o … .php#50469
http://www.php.net/manual/en/language.o … .php#64410
In the unit "User Contributed Notes"