Include one PHP file into another

I need to include one PHP file into another. The PHP file that needs to be included sits in a separate directory though. This is how it is set up:

folder1/global-functions.php
folder1/folder2/functions.php

I need to include the 'global-functions.php' in the 'functions.php'

I tried:

But this will not work. It returns this error message:

Warning: include(../global-functions.php) [function.include]: failed to open stream: No such file or directory in /home/user/public_html/wp-content/themes/folder1/folder2/custom_functions.php on line 2

Warning: include() [function.include]: Failed opening '../global-functions.php' for inclusion (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/user/public_html/wp-content/themes/folder1/folder2/custom_functions.php on line 2

Answer

Try including the file with an absolute path: something like this: