Why isn't global variable in PHP available to function in require_once file?

Question

In a PHP script, I define a global variable at the beginning of the script using $GLOBALS['someName'] = someValue. This global variable is then used by someFunction that is loaded later in the script using require. If I'm correct, I should be able to set $someName = someValue at the beginning of the script, and have $someName available globally. But, when I do this, $someName is not available to someFunction. It only works when I use $GLOBALS['someName']. Why doesn't $someName work as a global variable when defined at the beginning of the PHP script?

You need to tell PHP that you want to use the global variable in the function and not create a local one. Either with `global $someName;` or by using `$GLOBALS["someName"]` as you did. — Rizier123, Jun 25 '16 at 22:57
instead use $_SESSION or $_COOKIES..even $_SESSION is much better and safe...like $_SESSION['somename'] , it will work — Zaki Mustafa, Jun 25 '16 at 23:20
You need to provide source code when you ask questions like this. It is far easier to help you than reading a narrative. — Jonathan, Jun 25 '16 at 23:21
http://stackoverflow.com/questions/1557787/are-global-variables-in-php-considered-bad-practice-if-so-why — Jonathan, Jun 25 '16 at 23:23

Siraj Alam · Answer 1 · 2016-06-25T23:37:34.760

When you define a variable outside a function, so it is global in the page but not accessible in the functions. To make a variable global and use in other functions, There are two ways:

You have to use global keyword. So, just write global $someName in the beginning of the function, and then, use them normally in the function.
Do not redefine global variables as global $someName, but use them directly as $GLOBALS['someName'].

Go to this reference for more info.

score 1 · Answer 2 · edited May 23 '17 at 12:00

Okay let's give a proper example:

I will open up an interactive terminal in PHP to demonstrate accessing the global.

Interactive mode enabled
php > $myvar = "yves";
php > function testing() { echo $myvar; }; testing();
PHP Notice:  Undefined variable: myvar in php shell code on line 1
php > function testing_with_global() { global $myvar; echo $myvar; } 
php > testing_with_global();
yves
php >

Alternatively you can access the global with $GLOBALS['myvar'].

But you really don't want to do this. See why.

Why isn't global variable in PHP available to function in require_once file?

2 Answers2