SecAccessControlCreateWithFlags () in Swift

I am trying to call a function in Security.framework from swift code. Forgetting the "error" (last) parameter in a second if I call the function like this:

let accessControlRef = SecAccessControlCreateFlags(
            kCFAllocatorDefault,
            kSecAttrAccessibleWhenUnlockedThisDeviceOnly,
            SecAccessControlCreateFlags.UserPresence,
            nil
        )

      

        
        
        
      

    

I am getting the following error:

Cannot find an initializer for type SecAccessControlCreateFlags that takes a list of arguments of type '(CFAllocator !, CFStringRef, SecAccessControlCreateFlags, nil)'

... however, if I reformat my code to the following:

let allocator:CFAllocatorRef! = kCFAllocatorDefault

let protection:AnyObject!     = kSecAttrAccessibleWhenUnlockedThisDeviceOnly

let flags:SecAccessControlCreateFlags = SecAccessControlCreateFlags.UserPresence


let accessControlRef = SecAccessControlCreateWithFlags(
    allocator,
    protection,
    flags,
    nil
)

      

        
        
        
      

    

(the specific types - for example CFAllocatorRef

- are taken from the Xcode autocomplete function prototype) ... it compiles without issue. What's happening?

Next, the error parameter . What should I go through? While migrating my Objective-C code, I am tempted to pass the following variable (e.g. c &

):

var accessControlError:CFErrorRef! = nil

      

        
        
        
      

    

... which gives an error:

Unable to call "SecAccessControlCreateWithFlags" with an argument list of type (CFAllocatorRef !, AnyObject !, SecAccessControlCreateFlags, inout CFErrorRef!) '

If instead I pass in the following variable (again added with an operator-address):

var accessControlError:UnsafeMutablePointer<Unmanaged<CFError>?>

      

        
        
        
      

    

(same type as autocomplete prototype) I get:

Cannot call "SecAccessControlCreateWithFlags" with argument list of type (CFAllocatorRef !, AnyObject !, SecAccessControlCreateFlags, inout UnsafeMutablePointer?>) '

... so what gives?

EDIT: Forget the error. I seem to be taking the address twice (i.e. Pointer to Pointer). Instead, I have to do this:

var accessControlError:UnsafeMutablePointer<Unmanaged<CFError>?> = nil
// ^ Already a 'pointer'

let allocator:CFAllocatorRef!         = kCFAllocatorDefault
let protection:AnyObject!             = kSecAttrAccessibleWhenUnlockedThisDeviceOnly
let flags:SecAccessControlCreateFlags = SecAccessControlCreateFlags.UserPresence 

let accessControlRef = SecAccessControlCreateWithFlags(
        allocator,
        protection,
        flags,
        accessControlError // <- Notice the lack of '&'
)

      

        
        
        
      

    

Source: sample code in this answer .