Why Can't I Access a Global Variable Inside a PHP Function?

Unable to Access Global Variable Within Function

This script exhibits an issue where the global variable $sxml cannot be accessed within the foo() function:

$sxml = new SimpleXMLElement('<somexml/>');

function foo(){
    $child = $sxml->addChild('child');
}

foo();

Why This Occurs

Variables declared within the global scope cannot be directly referenced within functions unless they are explicitly defined as global within the function or passed as arguments.

Solutions

To access $sxml within foo(), there are several options:

1. Pass as an Argument:

function foo($sxml){
    $child = $sxml->addChild('child');
}
foo($sxml);

2. Declare as Global:

function foo(){
    global $sxml;
    $child = $sxml->addChild('child');
}
foo();

3. Create a Closure:

function bar() {
    $sxml = new SimpleXMLElement('<somexml/>');
    $foo = function() use(&amp;$xml) {
        $child = $sxml->addChild('child');
    };
    $foo();
}
bar();

4. Pass to Function Using Nested Function:

function bar() {
    $sxml = new SimpleXMLElement('<somexml/>');
    function foo() {
        $child = $sxml->addChild('child');
    }
    foo();
}
bar();

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