Check if a file was included or loaded

Question

Is there any elegant way to check if a file was included by using include/include_once/require/require_once or if the pag

Answer 1

if (defined('FLAG_FROM_A_PARENT'))
// Works in all scenarios but I personally dislike this

if (__FILE__ == get_included_files()[0])
// Doesn't work with PHP prepend unless calling [1] instead.

if (__FILE__ == $_SERVER['SCRIPT_FILENAME'])
// May break on Windows due to mixed DIRECTORY_SEPARATOR

if (basename(__FILE__) == basename($_SERVER['SCRIPT_FILENAME']))
// Doesn't work with files with the same basename but different paths

if (realpath(__FILE__) == realpath($_SERVER['SCRIPT_FILENAME']))
// Seems to do the trick as long as document root is properly configured

Note: On WAMP Servers virtual-hosts sometimes inherit the default document root setting, causing $_SERVER['DOCUMENT_ROOT'] to display wrong path.