PHP 8.3.4 Released!

$GLOBALS

(PHP 4, PHP 5, PHP 7, PHP 8)

$GLOBALSHace referencia a todas las variables disponibles en el ámbito global

Descripción

Es un array asociativo que contiene las referencias a todas la variables que están definidas en el ámbito global del script. Los nombres de las variables son las claves del array.

Ejemplos

Ejemplo #1 Ejemplo de $GLOBALS

<?php
function test() {
$foo = "variable local";

echo
'$foo en el ámbito global: ' . $GLOBALS["foo"] . "\n";
echo
'$foo en el ámbito simple: ' . $foo . "\n";
}

$foo = "Contenido de ejemplo";
test();
?>

El resultado del ejemplo sería algo similar a:

$foo en el ámbito global: Contenido de ejemplo
$foo en el ámbito simple: variable local

Notas

Nota:

Esta es una 'superglobal' o una variable automatic global. Significa simplemente que es una variable que está disponible en cualquier parte del script. No hace falta hacer global $variable; para acceder a la misma desde funciones o métodos.

Nota: Disponibilidad de las variables

A diferencia de todas las otras superglobals, $GLOBALS ha estado esencialmente siempre disponible en PHP.

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User Contributed Notes 4 notes

up
20
inafeeur at gmail dot com
1 year ago
We can be more clear with the extension of the given example.

Before PHP Version 8.1

<?php
$a
= 1;
$globals = $GLOBALS;
$globals['a'] = 2;
echo
$a; // 2
echo $globals['a']; // 2
echo $GLOBALS['a']; // 2
?>

After PHP Version 8.1

<?php
$a
= 1;
$globals = $GLOBALS;
$globals['a'] = 2;
echo
$a; // 1
echo $globals['a']; // 2
echo $GLOBALS['a']; // 1
?>
up
17
therandshow at gmail dot com
12 years ago
As of PHP 5.4 $GLOBALS is now initialized just-in-time. This means there now is an advantage to not use the $GLOBALS variable as you can avoid the overhead of initializing it. How much of an advantage that is I'm not sure, but I've never liked $GLOBALS much anyways.
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16
mstraczkowski at gmail dot com
10 years ago
Watch out when you are trying to set $GLOBALS to the local variable.

Even without reference operator "&" your variable seems to be referenced to the $GLOBALS

You can test this behaviour using below code

<?php
/**
* Result:
* POST: B, Variable: C
* GLOBALS: C, Variable: C
*/

// Testing $_POST
$_POST['A'] = 'B';

$nonReferencedPostVar = $_POST;
$nonReferencedPostVar['A'] = 'C';

echo
'POST: '.$_POST['A'].', Variable: '.$nonReferencedPostVar['A']."\n\n";

// Testing Globals
$GLOBALS['A'] = 'B';

$nonReferencedGlobalsVar = $GLOBALS;
$nonReferencedGlobalsVar['A'] = 'C';

echo
'GLOBALS: '.$GLOBALS['A'].', Variable: '.$nonReferencedGlobalsVar['A']."\n\n";
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13
vittorio.zamparella at famous googlemail
7 years ago
I finally found information about superglobals not being found in $GLOBALS:

https://bugs.php.net/bug.php?id=65223&edit=2
-------------------------------------
[2013-07-09 12:00 UTC] johannes @php.net
[...]super-globals (aka. auto globals) are not added to symbol tables by default for performance reasons unless the parser sees need. i.e.

<?php
$_SERVER
;
print_r($GLOBALS);
?>

will list it. You can also control this using auto_gloals_jit in php.ini: http://www.php.net/manual/en/ini.core.php#ini.auto-globals-jit
-------------------------------------

http://www.php.net/manual/en/language.variables.variable.php
-------------------------------------
Warning
Please note that variable variables cannot be used with PHP's Superglobal arrays within functions or class methods. The variable $this is also a special variable that cannot be referenced dynamically.
-------------------------------------
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