Swift basics - Availability Attribute

Availability Attribute:

Helps to ensure that a minimum OS is used:

if #available(iOS 9.0, OSX 10.10, watchOS 2, *){//requirements met}else{}

We can ensure that certain code is available where a certain OS is available:

@available(iOS 9.0, *) //means iOS 9 or later

func thisFunctionIsOnlyAvailableAfterIOS9(){}

@available(iOS 9.0, *) //means iOS 9 or later

struct thisStructureIsOnlyAvailableAfterIOS9{}