Apple API fsckup: how do I make unsafepointerof 0 a.k.a. NULL / 0x0 in swift?

Question

I have a case when parameter should have been UIViewController! to map from objc properly, but it is, sadly, UIViewController.

This

func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController currentVC: UIViewController) -> UIViewController? {
    guard unsafeAddressOf(currentVC).hashValue != 0 else { // 31316097 filed with apple

feels a bit fragile. hashValue might map to 0 for pointers other than 0x0. How do I make an unsafe pointer for NULL to compare unsafeAddressOf(currentVC) against?

Swift 2.3 in case it's a typical lets do with for swift 2 but but but we have made it much, much better in swift 3! Kind of answer is required.

`NULL` doesn't exist in Swift. There's `nil`, which is a shorthand for `Optional.none`. — Alexander, Mar 29 '17 at 06:42

score -1 · Answer 1 · answered Mar 29 '17 at 06:42

-1

currentVC can't be nil. It's not an Optional type.

answered Mar 29 '17 at 06:42

Alexander

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Indeed, it can not be nil. Swift bridging from obj-c ensures that. However NULL (0x00000000) pointers arrive into that function just fine. Which necessitates the dirty dance outlined in the question rather that simply doing guarded force unwrapping. – Anton Tropashko Mar 29 '17 at 06:43
@AntonTropashko That shouldn't be possible. The parameter should be imported into ObjC as `nonnull` – Alexander Mar 29 '17 at 06:44
Oh, I agree 100%. It shouldn't be possible. But it does happen. – Anton Tropashko Mar 29 '17 at 06:45
@AntonTropashko What's the function signature of the method once imported into ObjC? – Alexander Mar 29 '17 at 06:45
https://developer.apple.com/reference/uikit/uipageviewcontrollerdatasource/1614118-pageviewcontroller?language=objc – Anton Tropashko Mar 29 '17 at 06:51
@AntonTropashko Please create a complete, minimal, verifiable example. – Alexander Mar 29 '17 at 06:58

Apple API fsckup: how do I make unsafepointerof 0 a.k.a. NULL / 0x0 in swift?

1 Answers1