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:
Changelog
| Version | Description |
|---|---|
| 4.1.0 | Superglobals were introduced to PHP. |
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.
- Функция Суперглобальные переменные() - Суперглобальные переменные - это встроенные переменные, которые всегда доступны во всех областях видимости
- Функция $GLOBALS() - Ссылки на все переменные глобальной области видимости
- Функция $_SERVER() - Информация о сервере и среде исполнения
- Функция $_GET() - GET-переменные HTTP
- Функция $_POST() - HTTP POST variables
- Функция $_FILES() - Переменные файлов, загруженных по HTTP
- Функция $_REQUEST() - Переменные HTTP-запроса
- Функция $_SESSION() - Переменные сессии
- Функция $_ENV() - Переменные окружения
- Функция $_COOKIE() - HTTP Куки
- Функция $php_errormsg() - Предыдущее сообщение об ошибке
- Функция $HTTP_RAW_POST_DATA() - Необработанные POST-данные
- Функция $http_response_header() - Заголовки ответов HTTP
- Функция $argc() - Количество аргументов переданных скрипту
- Функция $argv() - Массив переданных скрипту аргументов
Коментарии
Since PHP 5.4, you cannot use a superglobal as the parameter to a function. This causes a fatal error:
function foo($_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 $get in the function, assuming that name is unique.
There was no deprecation warning issued in previous versions of PHP, according to my testing, neither in 5.3 nor 5.2. The error messages in 5.4 are:
Fatal error: Cannot re-assign auto-global variable _GET in...
Fatal error: Cannot re-assign auto-global variable _COOKIE in...
etc.
two bugs fixed in Mife's comment, but then it works:
<?php
// You do need global in this special situation
function get_var($varname){
global $$varname;
var_dump( $$varname);
}
get_var('_POST');
?>