UIInterfaceOrientationMask
Constants that specify a view controller’s supported interface orientations.
Declaration
struct UIInterfaceOrientationMaskOverview
Starting in iOS 8, you should employ the UITraitCollection and UITraitEnvironment APIs, and size class properties as used in those APIs, instead of using UIInterfaceOrientation constants or otherwise writing your app in terms of interface orientation.
In earlier versions of iOS, you returned these constants from the supportedInterfaceOrientations(for:) method or when determining which orientations to support in your app’s view controllers.