note 114426 added to function.define

Be aware that undefined constants are not evaluated the same as undefined variables (which is frustratingly counter-intuitive)... $ php -a php > if (!DO_IT) echo "don't do it\n"; else echo "do it\n"; do it php > var_dump(DO_IT); string(5) "DO_IT" php > if (!$DO_IT) echo "don't do it\n"; else echo "do it\n"; don't do it php > var_dump($DO_IT); NULL You have to specifically check for the definition like so... php > if(!defined('DO_IT') || (defined('DO_IT') && !DO_IT))echo "don't do it\n"; else echo "do it\n"; don't do it *sigh* ---- Server IP: 64.71.164.2 Probable Submitter: 75.147.180.77 ---- Manual Page -- http://php.net/manual/en/function.define.php Edit -- https://master.php.net/note/edit/114426 Del: integrated -- https://master.php.net/note/delete/114426/integrated Del: useless -- https://master.php.net/note/delete/114426/useless Del: bad code -- https://master.php.net/note/delete/114426/bad+code Del: spam -- https://master.php.net/note/delete/114426/spam Del: non-english -- https://master.php.net/note/delete/114426/non-english Del: in docs -- https://master.php.net/note/delete/114426/in+docs Del: other reasons-- https://master.php.net/note/delete/114426 Reject -- https://master.php.net/note/reject/114426 Search -- https://master.php.net/manage/user-notes.php