Warnings and Strict All code must compile and run cleanly with "use strict" enabled and the perl "-w" (warnings) option on. If you must do something that -w or strict complains about, there are workarounds, but the chances that you really need to do it that way are remote. The one exception is the "Use of uninitialized variable" warnings. We have those disabled in P5EE.pm, so by including "use P5EE" you are disabling that warning in your code, too, and you don't need to worry about them.