In online doc. at:
http://www.php.net/manual/en/language.oop5.basic.php
http://pl.php.net/manual/pl/language.oop5.basic.php
there is the same problem.

MR

Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php

Using $instance = null won't affect the object itself. $assigned still holds a reference to the object, as objects are assigned by reference in PHP5.

This problem is in Example 19-5. Object Assignment.
The result of code given in documentation is diferent then the shown one.
So I still think, that is a documentation bug.
Please execude code given in Example 19-5.
As I've written in first message moving line:
$instance->var = '$assigned will have this value';
just after <?PHP tag make this code giving right anwer.

MR

MR

still open

If the example was ...

[code]
<?php
class SimpleClass
{
   // member declaration
   public $var = 'a default value';

   // method declaration
   public function displayVar() {
       echo $this->var;
   }
}

$instance = new SimpleClass();

$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);
?>
[/code]

Then that would be more meaningfull. The documented example assumes that you are using the simple class and that you have created an instance of it. Without that the output is just junk.

E.g.

C:\>php
<?php
class SimpleClass
{
   // member declaration
   public $var = 'a default value';

   // method declaration
   public function displayVar() {
       echo $this->var;
   }
}

$instance = new SimpleClass();

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

C:\>

Running script containing above code gives proper result.
Problem is my misunderstanding of the example.
I'm closing the issue, but I suggest to change the way of giving examples.