Since PHP 5.4, you cannot use a superglobal as the parameter to a function. This causes a fatal error:
function foo($_GET) {
// whatever
}
It's called "shadowing" a superglobal, and I don't know why people ever did it, but I've seen it out there. The easy fix is just to rename the variable $get in the function, assuming that name is unique.
There was no deprecation warning issued in previous versions of PHP, according to my testing, neither in 5.3 nor 5.2. The error messages in 5.4 are:
Fatal error: Cannot re-assign auto-global variable _GET in...
Fatal error: Cannot re-assign auto-global variable _COOKIE in...
etc.
Superglobals
Superglobals — Superglobals are built-in variables that are always available in all scopes
Description
Several predefined variables in PHP are "superglobals", which means they are available in all scopes throughout a script. There is no need to do global $variable; to access them within functions or methods.
These superglobal variables are:
Notes
Note: Variable availability
By default, all of the superglobals are available but there are directives that affect this availability. For further information, refer to the documentation for variables_order.
Note: Dealing with register_globals
If the deprecated register_globals directive is set to on then the variables within will also be made available in the global scope of the script. For example, $_POST['foo'] would also exist as $foo.
For related information, see the FAQ titled "How does register_globals affect me?"
Note: Variable variables
Superglobals cannot be used as variable variables inside functions or class methods.
add a note
User Contributed Notes 3 notes
kitchin ¶
6 years ago
mife ¶
5 months ago
// You do need global in this special situation
function get_var($varname){
global $$varname;
echo $$varname;
}
show_var('_POST');
php (a) timstamp.co.uk ¶
2 years ago
For those wondering if register_globals also makes global variables available inside functions - it doesn't.
Running this code on a PHP52 webserver with register_globals enabled, using url:
http://localhost?hello=campers
<?php
function abc() {
echo "in func: '$hello' \n"; // outputs "in func: '' "
}
echo "global: '$hello' \n"; // outputs "global: 'campers' "
abc();
