I'm struggling with writing to an iCloud file. I want my IOS app to open files on the iCloud driver. I get the above error upon return from fopen(filename, "w"). Further, the container name (iCloud.TrackInstructor) appears in red under the iCloud stanza of the Signings & Capabilities page. I can see my container under the CloudKit page of my Apple Developer account. However, below, it states: Error loading container details. Also in red. FWIW, my app is trying to open: /private/var/mobile/Library/Mobile%20Documents/iCloud~TrackInstructor/Documents/nav_detailed_file_20220719_111330.csv I have IOS 15.5 and Xcode 13.4.1. I'm struggling. Help or ideas are appreciated.

I'd like to develop an application which acts as a Bluetooth Low Energy (BLE) peripheral. I am using Apple's Core Bluetooth library to implement a Sandbox app running under Mac OS where I'd like the Mac to serve as a BLE peripheral. To establish the connection, the Peripheral Manger Delegate must receive a status update of .poweredOn. What event sends that status update to the manager? Without that update, I cannot proceed with creating and registering the services and characteristics. I have Bluetooth checked under "App Sandbox" in the "Signing and Capabilities" sub window. Tahnks.

I've searched the web on this topic and can't find good info. I have a device (an ESP32 Programmable System on a Chip) and I'd like to sync its clock to that of the iPhone. (I want to sync the clocks so that I correctly fuse/align data collected by the ESP32 with GPS location data from the iPhone GPS receiver.) My current approach is to use NTP to sync the ESP32's clock to "network time" (available from time.apple.com) just like (I believe) the iPhone is doing. But, I would have to test the accuracy of this method as I'd __like to __ achieve an accuracy on the order of 0.01 seconds. (FYI: the ESP32 ecosystem provides NTP functionality.) I've considered syncing the ESP32 clock to GPS time (via an external GPS receiver) but I am told that GPS time is not available on IOS. Thus, I cannot use GPS time to correctly align/fuse measurement from the ESP32 with the iPhone. Thanks.

I found an example of some code which achieves my goal. However, I am getting the above error upon compiling. Searching on-line, I found solutions when the member in question was a variable, but not when it is a function. Here are excerpts: class ViewController : UIViewController { ... func printGreeting (modifier: UnsafePointer<CChar>) { print( ...) } var callbacks = SomeCLibCallbacks ( funcToCall: { (modifier)in printGreeting(modifier: modifier) //<- error here ) } }

Do Apples guidelines/recommendations/rules prohibit use of IPv4 on a WiFi connection between the iPhone and a non-Apple device (such as the Espressif ESP32 Programmable System on a Chip--PSoc) when: The ESP32 is a WiFi access point and the iPhone is a WiFi station? The iPhone is acting as a hotspot, communicating over the internet (for things such as a NTP server), and also communicating over WiFi to the ESP32, which is acting as a WiFi station? Thanks.

Hi I am developing an app which will provide near real-time feedback (ie, minimum speed in a turn) to drivers during track events. (Track events put a driver on a race track for either head-to-head racing or for teaching a driver to drive fast and safe on a race track.) I want the feedback to be audio (ie, a voice) rather than a display. But, there are so many options available (Siri, Carplay, notifications, etc) that I don't know what might be best. Right now, I'd just like the app to announce the contents of a UILabel. What would be your recommendations? In the very long term, I'd like the app to respond to driver's voice (for selecting which metric to feedback). My particular model year of car does not support CarPlay, so I'd have to rule CarPlay. (Beyond getting the app to talk, I also have to determine the best way to get the spoken messages to the driver. Do I use Bluetooth to connect to my car's audio, or use the remote audio plug of the car, or attempt to get the audio into the speakers many drivers have in their helmets. But that is a topic for another day...) Thanks for your feedback.

Hi I am developing an iPhone app which is somewhat numerically intensive. I'd like to save "telemetry"/debug data to memory and then be able to retrieve that data. Data will most likely be in form of a .csv file. Some have recommended NSLog. I am tempted to use fwrite() calls but don't know how to retrieve the generated file. I have searched the web for this info and have not found relevant info. Thanks.

I am comparing results from LocationsServices (particularly speed) with velocity reported by my ublox NEO-M9N receiver. I am 99% certain that I have correctly obtained the UTC time associated with each fix/speed from the receiver. I then compare that time series with the time series of speeds vs time from Core Location services. To align the 2, I must apply a time scale factor of ~ 0.6% to one to allow good alignment between the 2 time series. This is saying that time from Core Location is progressing at a different rate than the UTC time as reported by the GPS receiver. The Date/timestamp reported as part of CLLocations looks like a UTC. But, right now, I can't find anything definitive that it is a UTC. There are different flavors of UTC; the Naval Observatory has one flavor and NIST has another. Can anyone point me to definitive documentation clear stating what time is reported in the Date/timestamp in the CLLocation reported by LocationServices? I am hard pressed to believe that 2 versions of UTC could be so different. Thanks