allowDeferredLocationsUpdates working on the simulator but not on my iPhone 6s

问题

I'm trying to understand the deferredLocations feature. As per apple docs, the following should work, and it does when I run it on the simulator, but once I install the app on my iPhone 6s and disconnect the iPhone and run the app, the locations updates do not get deferred. I'm using XCode 8 and swift 3.

Here is the code:

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    locationManager=CLLocationManager()
    locationManager!.delegate=self

    locationManager!.desiredAccuracy=kCLLocationAccuracyBest
    locationManager!.requestAlwaysAuthorization()
    locationManager!.distanceFilter=kCLDistanceFilterNone
    locationManager!.allowsBackgroundLocationUpdates=true
    locationManager!.pausesLocationUpdatesAutomatically=false
    locationManager!.startUpdatingLocation()

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    if (!self.deferringUpdates)
    {
        locationManager!.allowDeferredLocationUpdates(untilTraveled: CLLocationDistanceMax, timeout: 60)
        self.deferringUpdates=true
    }
}

func locationManager(_ manager: CLLocationManager, didFinishDeferredUpdatesWithError error: Error?) {
    i=i+1
    label.text="\(i)"
    print("didFinishDeferredUpdatesWithError")
    locationManager!.disallowDeferredLocationUpdates()
    self.deferringUpdates=false
}

I'm getting error code = 11, which is GPS not available or something like that as per apple docs.

来源：https://stackoverflow.com/questions/39933965/allowdeferredlocationsupdates-working-on-the-simulator-but-not-on-my-iphone-6s