#45780 [Bgs]: why is it only expected for the user data parameter?

 ID:               45780
 User updated by:  Ultrasick at gmx dot de
-Summary:          array_walk ignores to pass reference if & is in
                   function definition at userdata
 Reported By:      Ultrasick at gmx dot de
 Status:           Bogus
 Bug Type:         Scripting Engine problem
 Operating System: probably any
 PHP Version:      5.2.6
 New Comment:

So do I also need to add a "&" before the "$my_array" to make changes
in array and not in a copy of the array? Like this:

array_walk(&$my_array, 'my_function', &$my_variable);


Previous Comments:
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[2008-08-11 18:23:34] [email protected]

 

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[2008-08-11 18:22:29] [email protected]

This is expected.

> array_walk($my_array, 'my_function', $my_variable);

The variable is passed by reference to my_function(), you can verify
that by adding an echo in the function.

But as you did not passed $my_variable by reference, array_walk() uses
its own copy of $my_variable, and this is that copy which is passed to
my_function().

So you need to pass it explicitly by reference to array_walk().

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[2008-08-11 03:45:45] Ultrasick at gmx dot de

Description:
------------
The function "array_walk" ignores to pass the reference and passes the
content instead for the parameter "userdata" if the "&" isn't written
inside the "array_walk()" but inside the function definition ("function
somename(&$value, &$key, &$userdata)"). This doesn't work for the
"userdata"-parameter but it does work for the "value" and the
"key"-parameter.

Have a look at the code at the bottom and the expected and the actual
result. Now compare what would happen if you would call "my_function"
manually by using

my_function($any_value, $any_key, $my_variable);
echo $my_variable;

and then using

my_function($any_value, $any_key, &$my_variable);
echo $my_variable;

In both cases $my_variable would be increased, of course.

So in my oppinion the userdata-problem it's not just inconsistency.
It's a bug because a part of the function definition is beeing ignored.

Reproduce code:
---------------
<?
function my_function(&$value, &$key, &$userdata){
	$userdata++;
}

$my_array = array('one', 'two', 'three');
$my_variable = 1;

array_walk($my_array, 'my_function', $my_variable);
echo $my_variable;

echo '<p><hr></p>';

array_walk($my_array, 'my_function', &$my_variable);
echo $my_variable;
?>

Expected result:
----------------
expected output:

4
-----------
4

Actual result:
--------------
actual output:

1
-----------
4


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-- 
Edit this bug report at http://bugs.php.net/?id=45780&edit=1