Difference between @available and #available in swift 2.0

Question

Swift 2.0 allows availability checking by using @available or #available, but what is the difference between using @available and #available?

Answer 1

You can use if #available to run version-specific code in small blocks, like the following :

if #available(iOS 9, *) {
    // use UIStackView for example
} else {
    // do something else
}

But what if whole methods are off limits, Or perhaps even whole classes? Swift 2 has these scenarios covered too, using the @available attribute.

@available(iOS 9, *)
func useStackView() {
    // use UIStackView for example
}

More details : https://www.hackingwithswift.com/new-syntax-swift-2-availability-checking