$GLOBALS

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

$GLOBALS — References all variables available in global scope

Descrizione

An associative array containing references to all variables which are currently defined in the global scope of the script. The variable names are the keys of the array.

Esempi

Example #1 $GLOBALS example

<?php

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

    echo '$foo in global scope: ' . $GLOBALS["foo"] . "\n";
    echo '$foo in current scope: ' . $foo . "\n";
}

$foo = "Example content";
test();

?>

Il precedente esempio visualizzerà qualcosa simile a:

$foo in global scope: Example content
$foo in current scope: local variable

Avviso

As of PHP 8.1.0, write access to the entire $GLOBALS array is no longer supported:

Example #2 writing entire $GLOBALS will result in error.

<?php

// Generates compile-time error:
$GLOBALS = [];
$GLOBALS += [];
$GLOBALS =& $x;
$x =& $GLOBALS;
unset($GLOBALS);
array_pop($GLOBALS);
// ...and any other write/read-write operation on $GLOBALS

?>

Note

Nota:
Questa è una variabile 'superglobale', o automaticamente global. Ciò semplicemente significa che è visibile in tutti gli ambiti in uno script. Non è necessario dichiararla come global $variable; per accedervi da funzioni o metodi.

Nota: Variable availability

Unlike all of the other superglobals, $GLOBALS has essentially always been available in PHP.

Nota:
As of PHP 8.1.0, $GLOBALS is now a read-only copy of the global symbol table. That is, global variables cannot be modified via its copy. Previously, $GLOBALS array is excluded from the usual by-value behavior of PHP arrays and global variables can be modified via its copy.

<?php // Before PHP 8.1.0 $a = 1; $globals = $GLOBALS; // Ostensibly by-value copy $globals['a'] = 2; var_dump($a); // int(2) // As of PHP 8.1.0 // this no longer modifies $a. The previous behavior violated by-value semantics. $globals = $GLOBALS; $globals['a'] = 1; // To restore the previous behavior, iterate its copy and assign each property back to $GLOBALS. foreach ($globals as $key => $value) { $GLOBALS[$key] = $value; } ?>