Global Variables

Variables that reside in the global scope, and may be imported with the global keyword.

To become a global variable, a variable may use one of the following ways:

  • Be declared as such with the global keyword

  • Be created in the $GLOBALS variable, which is a global variable itself

  • Be created outside any function, method, closure

  • Be a super-global

Global variables provides a way to share data in different and remote scopes. It also provide a way for data to be modified by another part of the code, without warning.

<?php


global $count;
$count = 0;

function counter() {
    global $count;

    // no return here
    ++$count;
}

counter();
echo $count; // print 1
counter();
echo $count; // print 2

?>

Documentation

Related : Variables, Static Variables, Variable Variables, $GLOBALS, global Scope, Superglobal Variables, Distributed State, $GLOBALS, Hidden State, Implicit State, Legacy, Local Variable