As of PHP 4.0.4, this function is an alias for get_included_files()
In PHP 4.0.1pl2 and previous versions get_required_files() assumed that the required files ended in the extension .php, other extensions would not be returned. The array returned by get_required_files() was an associative array and only listed files included by require() and require_once().
See also: require(), require_once(), include(), include_once() and get_included_files().