When we start a constant name with space, it doesn't produce any error.
<?php
define (" YEAR", 2000)
echo "success";
?>
output: success
But when we call this constant, it produce error.
<?php
define (" YEAR", 2000)
echo YEAR;
?>
output: E_NOTICE : type 8 -- Use of undefined constant YEAR - assumed 'YEAR' -- at line 4 YEAR