Is there a way to disable PHP from outputting warnings?

error_reporting(E_ALL ^ E_WARNING); (iirc)

This may be helpful too

Or, if you don't care about ANY verbose:
error_reporting(E_NONE);

Sorry to bump this post, but it may be helpful to note that if you only want to disable warning or error reporting for a single function call, prefix the call with an @.

Ex: @setcookie