EllisLab/CodeIgniter — pull request #1548 by chrisguiney (2012-06-29 04:37:40+00:00)
Title: Respect display_errors when deciding if to display an error... 

-- useful for environments where you want to log errors, but not show them.

Pretty self explanatory, it just checks ini_get('display_errors') to see if it's a positive value or not before actually showing an error.