$GLOBALS

$GLOBALS — 引用全局作用域中可用的全部变量

说明

一个包含了全部变量的全局组合数组。变量的名字就是数组的键。

范例

Example #1 $GLOBALS 范例


<?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();
?>

以上例程的输出类似于：

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

注释

Note:
“Superglobal”也称为自动化的全局变量。这就表示其在脚本的所有作用域中都是可用的。不需要在函数或方法中用 global $variable; 来访问它。

Note: 变量可用性

与所有其他超全局变量不同，$GLOBALS在PHP中总是可用的。

$_SERVER

超全局变量

[edit] Last updated: Fri, 25 May 2012

add a note User Contributed Notes $GLOBALS

Gratcy 13-May-2012 07:03


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)



*/

?>

therandshow at gmail dot com 29-Jun-2011 06:32


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.

williams at 3cisd dot com 28-Jul-2009 03:53


Better yet, use print_r.  While var_dump does detect the recursion that var_export fails on, it seems to recurse one level first for my setup.  So var_dump ends up printing all globals twice, but print_r prints them only once since it detects the recursion right away.  Serialize seems to not detect the recursion at all either, similar to var_export.

David 14-Aug-2008 05:47


Though you can use var_dump to output the value of $GLOBALS.

ravenswd at yahoo dot com 12-Aug-2008 01:02


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?"

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