require_once in Moodle (Notice: Trying to get property of non-object in...)

Question

I am trying to write an enrol plugin for moodle and therefor I need the functions of the /moodle/enrol/cohort/lib.php file.

But when I try

global $CFG;

require_once($CFG->dirroot . '../lib.php');

it gives me

Notice: Trying to get property of non-object in /var/www/html/moodle/enrol/cohort/enrol_module/result.php on line 20

line 20 is

require_once($CFG->dirroot . '../lib.php');

The Path should be correct. Can someone tell me what is responsible for this?

Answer 1

@Chris Lear thanks, you were right:) I included the file where $CFG is set:

require_once('../../../config.php');

the second require part was wrong, too

require_once($CFG->dirroot.'/enrol/cohort/lib.php');

global $CFG;