Whither dispatch_once in Swift 3?

Question

Okay, so I found out about the new Swifty Dispatch API in Xcode 8. I\'m having fun using DispatchQueue.main.async, and I\'ve been browsing around the Disp

Answer 1

According to the Migration Guide:

The free function dispatch_once is no longer available in Swift. In Swift, you can use lazily initialized globals or static properties and get the same thread-safety and called-once guarantees as dispatch_once provided.

Example:

  let myGlobal = { … global contains initialization in a call to a closure … }()

  // using myGlobal will invoke the initialization code only the first time it is used.
  _ = myGlobal