Mutability and Reference of PHP5 GET Variables

Question

I have the following in a page e.g. /mypage?myvar=oldvalue

$_SESSION['myvar'] = $_GET['myvar'];
$myvar = 'a_new_string'

Now $_SESSION['myvar'] has the value 'a_new_string'

Is this by design?

How can I copy the value of 'myvar' rather than a reference to it?

Answer 1

I don't believe it's by design, but it can certainly be annoying.

Answer 2

It's a feature not a bug :-)

luckily you can turn it off, set register_globals = off in your php.ini

Answer 3

I've tested this with register_globals on and off and can't reproduce it. What version of PHP are you using (I'm on 5.2.6).

Answer 4

After running this:

<?php
session_start(); 
$_GET['myvar'] = ''; 
$_SESSION['myvar'] = $_GET['myvar']; 
$myvar = 'a_new_string'; 
var_dump($_SESSION); 
?>

on PHP 5.2.6 I get this:

array(1) { ["myvar"]=>  string(0) "" }

Answer 5

register_globals is the invention of the devil. Fortunately in PHP 6.0 it will be entirely disabled. It wasn't just a huge security problem, it makes people confuse. Please turn it off in your php.ini using register_globals = Off More information: http://us2.php.net/register_globals Also you can check the current settings with the command if (ini_get(register_globals)) echo "turn it off! :)';