EllisLab/CodeIgniter — pull request #1462 by dwaynehale (2012-06-12 17:23:36+00:00)
Title: Changed set_cookie functions to take int 0 instead of empty string ''

According to PHP's definition of setcookie the expire parameter accepts a integer, not a empty string as before. If a user was to call set_cookie without specifying a expire value, it would default to a empty string.