PHP Unconference Europe 2015

$GLOBALS

(PHP 4, PHP 5)

$GLOBALSReferences all variables available in global scope

Opis

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.

Przykłady

Przykład #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();
?>

Powyższy przykład wyświetli coś podobnego do:

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

Notatki

Informacja:

To jest zmienna "superglobalna" lub automatycznie ustawiona na globalną. To po prostu oznacza, że jest dostępna w każdym miejscu skryptu. Nie jest konieczne użycie global $zmienna; aby mieć do niej dostęp w funkcjach i metodach.

Informacja: Variable availability

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

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User Contributed Notes 5 notes

up
11
therandshow at gmail dot com
3 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.
up
5
mstraczkowski at gmail dot com
1 year 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";
up
-12
bkilinc at deyta dot net
1 year ago
I prefer accessing globals through static function calls. Source code looks better; I use glb::get('myglobalvar') instead of $GLOBALS['myglobalvar']. This gives me full control over global access, which can be the source of problems in practice.

class glb
{
    static public function set($name, $value)
    {
        $GLOBALS[$name] = $value;
    }

    static public function get($name)
    {
        return $GLOBALS[$name];
    }

}

$myglobalvar = 'Hello, World !';

function myfunction()
{
    $val = glb::get('myglobalvar');
    echo "$val\n";
    glb::set('myglobalvar', 'hi, again :)');
    $val = glb::get('myglobalvar');
    echo "$val\n";
}

myfunction();
up
-18
ravenswd at yahoo dot com
6 years ago
Keep in mind that $GLOBALS is, itself, a global variable. So code like this won't work:

<?php
   
print '$GLOBALS = ' . var_export($GLOBALS, true) . "\n";
?>

This results in the error message: "Nesting level too deep - recursive dependency?"
up
-37
Gratcy
2 years ago
this is technique that i always did for configuration file..

<?php
$conf
['conf']['foo'] = 'this is foo';
$conf['conf']['bar'] = 'this is bar';

function
foobar() {
    global
$conf;
   
var_dump($conf);
}

foobar();

/*
result is..

array
  'conf' =>
    array
      'foo' => string 'this is foo' (length=11)
      'bar' => string 'this is bar' (length=11)

*/
?>
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