iphone xcode Landscape mode by default

Question

how can I set an iphone app to start in Landscape mode? and stays that way

Answer 1

Marcelo's answer is not correct, because UIInterfaceOrientationLandscape is not a valid identifier and thus brings up a build fail.

progrmr's answer is correct:

return interfaceOrientation == UIInterfaceOrientationLandscapeLeft || interfaceOrientation == UIInterfaceOrientationLandscapeRight;

(Apologies for not commenting on the first answer, but I didn't have enough reputation points when I wrote this...)