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Bug #41214 referencing a reference parameter on a function-local variable does not work
Submitted: 2007-04-27 17:04 UTC Modified: 2007-04-27 17:15 UTC
From: php at warhog dot net Assigned:
Status: Not a bug Package: Variables related
PHP Version: 5.2.1 OS: Linux (Ubuntu 6.10/Linux 2.6.17)
Private report: No CVE-ID: None
 [2007-04-27 17:04 UTC] php at warhog dot net
Description:
------------
When having a reference-variable as parameter in a function and 
referencing it on a local variable (inside the function) the 
variable will keep the referenced value inside the function but not 
outside. That's not the way I understand references in PHP.

Reproduce code:
---------------
<?php
function yet_another_function(&$foo)
{
	$_foo = 3;
	$foo =& $_foo;
	var_dump($foo);
}

yet_another_function($bar);
var_dump($bar);
?>


Expected result:
----------------
int(3)
int(3)


Actual result:
--------------
int(3)
NULL


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 [2007-04-27 17:11 UTC] tony2001@php.net
You're creating a reference to the variable that exists only in the function scope.
 [2007-04-27 17:15 UTC] php at warhog dot net
Same thing in PHP 5.1.6 (from the official ubuntu repositories).

I thought about the problem and considered the fact that a local 
variable vanishes when the function is done... so I tried the same 
with a static variable.. but it didn't work either:

<?php
function some_function(&$foo)
{
	static $_foo = NULL;

	if (is_null($_foo)) {
		$_foo = 1;
	}

	var_dump($_foo);
	$foo =& $_foo;
	var_dump($foo);
}

function some_other_function(&$foo)
{
	$foo = 2;
}

function yet_another_function(&$foo)
{
	$_foo = 3;
	$foo =& $_foo;
	var_dump($foo);
}

some_function($bar);
var_dump($bar);

some_other_function($bar);
var_dump($bar);

yet_another_function($bar);
var_dump($bar);
?>

Expected:
---------

int(1)
int(1)
int(1)
int(2)
int(3)
int(3)

Actual Result:
--------------

int(1)
int(1)
NULL
int(2)
int(3)
int(2)
 
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