What does the PHP error message “Notice: Use of undefined constant” mean?

Question

PHP is writing this error in the logs: \"Notice: Use of undefined constant\".

Error in logs:

PHP Notice:  Use of undefined constant          


        

Answer 1

Insert single quotes.

Example

$department = mysql_real_escape_string($_POST['department']);
$name = mysql_real_escape_string($_POST['name']);
$email = mysql_real_escape_string($_POST['email']);
$message = mysql_real_escape_string($_POST['message']);