Processes & Concurrency

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Processes & Concurrency Resources
General: DevForums subtopic: App & System Services > Processes & Concurrency Processes & concurrency covers a number of different technologies: Background Tasks Resources Concurrency Resources — This includes Swift concurrency. Service Management Resources XPC Resources Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com"
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Where did I screw up trying concurrency?
I tried making a concurrency-safe data queue. It was going well, until memory check tests crashed. It's part of an unadvertised git project. Its location is: https://github.com/CTMacUser/SynchronizedQueue/commit/84a476e8f719506cbd4cc6ef513313e4e489cae3 It's the blocked-off method "`memorySafetyReferenceTypes'" in "SynchronizedQueueTests.swift." Note that the file and its tests were originally AI slop.
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Capturing screen buffer at macOS Login Window with ScreenCaptureKit and PrivilegedHelper
I am developing a remote support tool for macOS. While we have successfully implemented a Privileged Helper Tool and LaunchDaemon architecture that works within an active Aqua session, we have observed a total failure to capture the screen buffer or receive input at the macOS Login Window. Our observation of competitor software (AnyDesk, TeamViewer) shows they maintain graphical continuity through logout/restart. We are seeking the official architectural path to replicate this system-level access. Current Technical Implementation Architecture: A root-level LaunchDaemon manages the persistent network connection. A PrivilegedHelperTool (installed in /Library/PrivilegedHelperTools/) is used for elevated tasks. Environment: Tested on macOS 14.x (Sonoma) and macOS 15.x (Sequoia) on Apple Silicon. Capture Methods: We have implemented ScreenCaptureKit (SCK) as the primary engine and CGDisplayCreateImage as a fallback. Binary Status: All components are signed with a Developer ID and have been successfully Notarized. Observed Behavior & Blockers The "Aqua" Success: Within a logged-in user session, our CGI correctly identifies Display IDs and initializes the capture stream. Remote control is fully functional. The "Pre-Login" Failure: When the Mac is at the Login Window (no user logged in), the following occurs: The Daemon remains active, but the screen capture buffer returns NULL or an empty frame. ScreenCaptureKit fails to initialize, citing a lack of graphical context. No TCC (Transparency, Consent, and Control) prompt can appear because no user session exists. The "Bootstrap" Observation: We have identified that the loginwindow process exists in a restricted Mach bootstrap namespace that our Daemon (running in the System domain) cannot natively bridge. Comparative Analysis (Competitor Benchmarking) We have analyzed established remote desktop solutions like AnyDesk and Jump Desktop to understand their success at the login screen. Our findings suggest: Dual-Context Execution: They appear to use a Global LaunchAgent with LimitLoadToSessionType = ["LoginWindow"]. This allows a child process to run as root inside the login window’s graphical domain. Specialized Entitlements: These apps have migrated to the com.apple.developer.persistent-content-capture entitlement. This restricted capability allows them to bypass the weekly/monthly TCC re-authorization prompts and function in unattended scenarios where a user cannot click "Allow." Questions Entitlement Requirement: Is the persistent-content-capture entitlement the only supported way for a third-party app to capture the LoginWindow buffer without manual user intervention? LaunchAgent Strategy: To gain a graphical context at the login screen, is it recommended to load a specialized agent into the loginwindow domain via launchctl bootstrap loginwindow ...? ScreenCaptureKit vs. Legacy: Does ScreenCaptureKit officially support the LoginWindow session, or does it require an active Aqua session to initialize? MDM Bypass: For Enterprise environments, can a Privacy Preferences Policy Control (PPPC) payload grant "Screen Recording" to a non-entitled Daemon specifically for the login window context?
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In the context of Live Activity, when app is launched into background due to some callback, should you wrap your work with background tasks?
I'm specifically focused on Live Activity, but I think this is somewhat a general question. The app could get a few callbacks when: There's a new payload (start, update, end) There's a new token (start, update) There's some other lifecycle event (stale, dismissed) Assuming that the user didn't force kill the app, would the app get launched in all these scenarios? When OS launches the app for a reason, should we wrap our tasks with beginBackgroundTask or that's unnecessary if we're expecting our tasks to finish within 30 seconds? Or the OS may sometimes be under stress and give you far less time (example 3 seconds) and if you're in slow internet, then adding beginBackgroundTask may actually come in handy?
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GUI + XPC Service App Architecture Performance
Let's image that someone wants to use a background service to keep track of FSEvents activity, at the file level (a firehose, some might say). I choose this example, to indicate the volume and rate of data transmission in question. I'm not creating a front-end for FSEvents data, but my background service may generate data at a similar pace. The service runs off of user defined document/s that specify the FSEvent background filtering to be applied. Those that match get stored into a database. But filters can match on almost all the data being emitted by FSEvents. The user decides to check on the service's activity and database writes by launching a GUI that sends requests to the background service using XPC. So the GUI can request historic data from a database, but also get a real-time view of what FS events the service is busy filtering. So it's a client-server approach, that's concerned with monitoring an event stream over XPC. I understand XPC is a request/response mechanism, and I might look into using a reverse connection here, but my main concern is one of performance. Is XPC capable of coping with such a high volume of data transmision? Could it cope with 1000s of rows of table data updates per second sent to a GUI frontend? I know there are streaming protocol options that involve a TCP connection, but I really want to stay away from opening sockets.
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application(_:didFinishLaunchingWithOptions:) not called on MDM iPads after overnight idle — app resumes without cold start
We are seeing a strange lifecycle issue on multiple MDM-managed iPads where application(_:didFinishLaunchingWithOptions:) is not called after the device is idle overnight. Even if we terminate the app manually via the app switcher, the next morning the system does not perform a cold launch. Instead, the app resumes directly in: applicationDidBecomeActive(_:) This causes all initialization logic that depends on didFinishLaunching to be completely skipped. This behavior is consistent across four different supervised MDM devices. Environment Devices: iPads enrolled in MDM (supervised) iOS version: 18.3 Xcode: 16.4 macOS: Sequoia 15.7.2 App type: Standard UIKit iOS app App: Salux Audiometer (App Store app) Expected Behavior If the app was terminated manually using the app switcher, the next launch should: Start a new process Trigger application(_:didFinishLaunchingWithOptions:) Follow the normal cold-start lifecycle Actual Behavior After leaving the iPad idle overnight (8–12 hours): The next launch skips didFinishLaunching The app resumes directly in applicationDidBecomeActive No new process is started App behaves as if it had been suspended, even though it was manually terminated Logs (Relevant Extracts) Day 1 — Normal cold launch [12:06:44.152 PM] PROCESS_STARTED [12:06:44.214 PM] DID_FINISH_LAUNCHING_START launchOptions=[] [12:06:44.448 PM] DID_FINISH_LAUNCHING_END We then used the app and terminated it via app switcher. Day 2 — Unexpected resume without cold start [12:57:49.328 PM] APP_DID_BECOME_ACTIVE No PROCESS_STARTED No didFinishLaunching No cold-start logs This means the OS resumed the app from a previous state that should not exist. Reproducible Steps Use an MDM-enrolled iPad. Launch the app normally. Terminate it manually via the multitasking app switcher. Leave the device idle overnight (8–12 hours). Launch the app the next morning. Observe that: didFinishLaunching does not fire applicationDidBecomeActive fires directly Questions for Apple Engineers / Community Is this expected behavior on MDM-supervised devices in iOS 18? Are there any known OS-level changes where terminated apps may be revived from disk/memory? Could MDM restrictions or background restoration policies override app termination? How can we ensure that our app always performs a clean initialization when launched after a long idle period? Additional Information We have full logs from four separate MDM iPads showing identical behavior. Happy to share a minimal reproducible sample if required.
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BGProcessingTask Not Triggering at Scheduled Time After Updating to Xcode 26.1.1
I’m reaching out regarding an issue we’ve been experiencing with BGProcessingTask since upgrading to Xcode 26.1.1. Issue Summary Our daily background processing task—scheduled shortly after end‑of‑day—has stopped triggering reliably at night. This behavior started occurring only after updating to Xcode 26.1.1. Prior to this update, the task consistently ran around midnight, executed for ~10–15 seconds, and successfully rescheduled itself for the next day. Expected Behavior BGProcessingTask should run at/near the scheduled earliestBeginDate, which we set to roughly 2 hours after end-of-day. The task should execute, complete, and then reschedule itself. Actual Behavior On devices running builds compiled with Xcode 26.1.1, the task does not trigger at all during the night. The same code worked reliably before the Xcode update. No system logs indicate rejection, expiration, or background task denial. Technical Details This is the identifier we use: private enum DayEndProcessorConst {    static let taskIdentifier = "com.company.sdkmanagement.daysummary.manager" } The task is registered as follows: When app launched BGTaskScheduler.shared.register(    forTaskWithIdentifier: DayEndProcessorConst.taskIdentifier,    using: nil ) { [weak self] task in    self?.handleDayEndTask(task) } And scheduled like this: let date = Calendar.current.endOfDay(for: Date()).addingTimeInterval(60 * 60 * 2) let request = BGProcessingTaskRequest(identifier: DayEndProcessorConst.taskIdentifier) request.requiresNetworkConnectivity = true request.requiresExternalPower = false request.earliestBeginDate = date try BGTaskScheduler.shared.submit(request) As per our logs, tasks scheduled successfully The handler wraps the work in an operation queue, begins a UI background task, and marks completion appropriately: task.setTaskCompleted(success: true) Could you please advise whether: There are known issues with BGProcessingTask scheduling or midnight execution in Xcode 26.1.1 or iOS versions associated with it? Any new entitlement, configuration, or scheduler behavior has changed in recent releases? Additional logging or diagnostics can help pinpoint why the scheduler never fires the task?
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Can an app launch automatically after watchOS restarts?
Regarding App Update Synchronization During Workout Mode: My watchOS app has workout mode enabled. When I update the app from the App Store on my iPhone while a workout session is active on my Apple Watch, the update does not sync to the watch. Why does this happen, and when can I expect the watch app to be updated? Regarding Automatic App Launch After a Prolonged Shutdown: I would like my watchOS app to launch automatically on my Apple Watch after it has been powered off for an extended period and then turned back on. Is this functionality possible to implement? If not, please provide a definitive answer regarding this capability.
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nonisolated Execution Differences Before and After Xcode 26.2
I have an older project that was created before Xcode 26.2. In Xcode versions prior to 26.2, there was no Swift Compiler – Concurrency build setting. With those older versions, the following behavior occurs: a nonisolated function executes off the main thread. class ViewController: UIViewController { override func viewDidLoad() { super.viewDidLoad() run() } private func run() { Task { await runInMainThread() } } func runInMainThread() async { print(">>>> IN runInMainThread(), Thread.isMainThread \(Thread.isMainThread)") await runInBackgroundThread() } private nonisolated func runInBackgroundThread() async { print(">>>> IN runInBackgroundThread(), Thread.isMainThread \(Thread.isMainThread)") } } Output: >>>> IN runInMainThread(), Thread.isMainThread true >>>> IN runInBackgroundThread(), Thread.isMainThread false However, starting with Xcode 26.2, Apple introduced the Swift Compiler – Concurrency settings. When running the same code with the default configuration: Approachable Concurrency = Yes Default Actor Isolation = MainActor This is the output Output: >>>> IN runInMainThread(), Thread.isMainThread true >>>> IN runInBackgroundThread(), Thread.isMainThread true the nonisolated function now executes on the main thread. This raises the following questions: What is the correct Swift Compiler – Concurrency configuration if I want a nonisolated function to run off the main thread? Is nonisolated still an appropriate way to ensure code runs on a background thread?
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Behavior of BGContinuedProcessingTask on Failure
Hi there, First thanks for all the work on BGContinuedProcessingTask! It looks really promising. I have a question / issue around the behavior when a BGContinuedProcessingTask expires. Here is my setup. I have an app who's responsible for uploading large files in the field (AKA wifi is not expected) For a given file, it can likely fail due to network conditions I'm using Multipart upload though so I can retry a file to pick up where it left off. I use one taskIdentifier per file, and when the file fails, I can retry the task and have it continue where it left off (I am reusing the taskIdentifier here for retries, let me know if I shouldn't be doing that) Here is the behavior I am seeing I start an upload, it seems to be uploading normally I turn on airplane mode to simulate expiration of the task the task fails as expected after ~30 seconds, and I see the failure in my home screen. I have callbacks in the task to put my app in the proper state on expiration / failure I turn back on airplane mode and I retry the task, the way I do this is I do NOT re-register, I simply re-submit the task with the same TaskIdentifier. What I would have expected is that the failure task is REPLACED with the new task and new progress. Instead what I see is TWO ContinuedBackgroundProcessingTasks, one in the failure state and one in progress. My question is How can I make retries reuse the same task notification item? OR if that's not possible, how do I programmatically clear the task failure? I've tried cancelTask but that doesn't seem to clear it.
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How do I internally handle conditionally conforming to ConnectablePublisher
I'm making an operator Publisher, which has to wrap the upstream publisher. But I want the operator to conditionally conform to ConnectablePublisher, but only when the upstream publisher does the same. I can make my connect() call the upstream's connect(), but is that all I have to do? That Apple's plumbing will automatically hold back the initial call to the Subscription object if the publisher is connectable. Otherwise, I need to make a flag in the subscription for when to connect, which would involve an infinitely copyable struct somehow send a message to a unique class/actor. That last part makes sense to me, but it also seems like too much work for something plug-and-play. Having Apple's implementation taking care of that issue also makes sense, and would be a better solution.
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MacOS 26 TestFlight SIGKILLs app when updating
We're developing an Electron app for MacOS App Store. When updating our app through TestFlight, TestFlight prompts "Close This App to Update", and when I click "Continue" our app would be "Terminated" for update. Now this is where things go wrong. On MacOS 15 our app seems to be gracefully terminating (We attached it with lldb and it shows that our app returns with 0 when we click "Continue") which is fine. However for MacOS 26 though, it seems that TestFlight just directly SIGKILLs our app (indicated by lldb), which means that all of our app's child processes are left orphaned. Even worse, our app is singleton, which means that when the app relaunches it fails, because the leftover child processes from the previously SIGKILLed session is still alive, and even if we want to kill those orphaned child processes we can't because our app is sandboxed thus cannot kill processes outside of the current sandbox. We captured output from log stream (app name redacted): 12-02 22:08:16.477036-0800 0x5452     Default     0x5a4a7              677    7    installcoordinationd: [com.apple.installcoordination:daemon] -[IXSCoordinatorProgress setTotalUnitsCompleted:]: Progress for coordinator: [com.our.app/Invalid/[user-defined//Applications/OurApp.app]], Phase: IXCoordinatorProgressPhaseLoading, Percentage: 99.454 123: Attempt to set units completed on finished progress: 214095161 2025-12-02 22:08:16.483056-0800 0x53ba     Default     0x5a5c9              167    0    runningboardd: (RunningBoard) [com.apple.runningboard:connection] Received termination request from [osservice<com.apple.installcoordinationd(274)>:677] on <RBSProcessPredicate <RBSProcessBundleIdentifierPredicate "com.our.app">> with context <RBSTerminateContext| explanation:installcoordinationd app:[com.our.app/Invalid/[user-defined//Applications/OurApp.app]] uuid:A3BC0629-124E-4165-ABB7-1324380FC354 isPlaceholder:N re portType:None maxTerminationResistance:Absolute attrs:[ 2025-12-02 22:08:16.488651-0800 0x53ba     Default     0x5a5c9              167    7    runningboardd: (RunningBoard) [com.apple.runningboard:ttl] Acquiring assertion targeting system from originator [osservice<com.apple.installcoordinationd(274)>:677] with description <RBSAssertionDescriptor| "installcoordinationd app:[com.our.app/Invalid/[user-defined//Applications/OurApp.app]] uuid:A3BC0629-124E-4165-ABB7-1324380FC354 isPlaceholder:N" ID:167-677-1463 target:system attributes:[ 2025-12-02 22:08:16.489353-0800 0x53ba     Default     0x5a5c9              167    0    runningboardd: (RunningBoard) [com.apple.runningboard:process] [app<application.com.our.app.485547.485561(501)>:2470] Terminating with context: <RBSTerminateContext| explanation:installcoordinationd app:[com.our.app/Invalid/[user-defined//Applications/OurApp.app]] uuid:A3BC0629-124E-4165-ABB7-1324380FC354 isPlaceholder:N reportType:None maxTerminationResistance:Absolute attrs:[ 2025-12-02 22:10:23.920869-0800 0x5a5a     Default     0x5a4c6              674    14   appstoreagent: [com.apple.appstored:Library] [A95D57D7] Completed with 1 result: <ASDApp: 0xc932a8780>: {bundleID = com.our.app; completedUnitCount = 600; path = /Applications/OurApp.app; installed = 0} 2025-12-02 22:10:32.027304-0800 0x5ae5     Default     0x5a4c7              674    14   appstoreagent: [com.apple.appstored:Library] [BEB5F2FD] Completed with 1 result: <ASDApp: 0xc932a8780>: {bundleID = com.our.app; completedUnitCount = 600; path = /Applications/OurApp.app; installed = 0} 2025-12-02 22:10:36.542321-0800 0x5b81     Default     0x5a4c8              674    14   appstoreagent: [com.apple.appstored:Library] [185B9DD6] Completed with 1 result: <ASDApp: 0xc932a8780>: {bundleID = com.our.app; completedUnitCount = 600; path = /Applications/OurApp.app; installed = 0} The line "Terminating with context" seems suspicious. This line is not seen on MacOS 15, only MacOS 26. Is this documented behavior? If so, how can we handle this?
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What DispatchQueues should i use for my app's communication subsystem?
We would be creating N NWListener objects and M NWConnection objects in our process' communication subsystem to create server sockets, accepted client sockets on server and client sockets on clients. Both NWConnection and NWListener rely on DispatchQueue to deliver state changes, incoming connections, send/recv completions etc. What DispatchQueues should I use and why? Global Concurrent Dispatch Queue (and which QoS?) for all NWConnection and NWListener One custom concurrent queue (which QoS?) for all NWConnection and NWListener? (Does that anyways get targetted to one of the global queues?) One custom concurrent queue per NWConnection and NWListener though all targetted to Global Concurrent Dispatch Queue (and which QoS?)? One custom concurrent queue per NWConnection and NWListener though all targetted to single target custom concurrent queue? For every option above, how am I impacted in terms of parallelism, concurrency, throughput &amp; latency and how is overall system impacted (with other processes also running)? Seperate questions (sorry for the digression): Are global concurrent queues specific to a process or shared across all processes on a device? Can I safely use setSpecific on global dispatch queues in our app?
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Some fundamental doubts about DisptachQueue and GCD
I understand that GCD and it's underlying implementations have evolved over time. And many things have not been shared explicitly in Apple documentation. The most concepts of DispatchQueue (serial and concurrent queues), DispatchQoS, target queue and system provided queues: main and globals etc. I have some doubts & questions to clarify: [Main Dispatch Queue] [Link] Because the main queue doesn't behave entirely like a regular serial queue, it may have unwanted side-effects when used in processes that are not UI apps (daemons). For such processes, the main queue should be avoided. What does it mean? Can you elaborate? [Global Concurrent Dispatch Queues] Are they global to a process or across processes on a device. I believe it is the first case but just wanted to be sure. [Global Concurrent Dispatch Queues] Does system create 4 (for each QoS) * 2 (over-commiting and non-overcommiting queues) = 8 queues in all. When does which type of queue comes into play? [Custom Queue][Target Queue concept] [swift-corelibs-libdispatch/man/dispatch_queue_create.3] QUOTE The default target queue of all dispatch objects created by the application is the default priority global concurrent queue. UNQUOTE Is this stil true? We could not find a mention of this in any latest official apple documentation (though some old forum threads (one more) and github code documentation indicate the same). The official documentation only says: [dispatch_set_target_queue] QUOTE If you want the system to provide a queue that is appropriate for the current object UNQUOTE [dispatch_queue_create_with_target] QUOTE Specify DISPATCH_TARGET_QUEUE_DEFAULT to set the target queue to the default type for the current dispatch queue.UNQUOTE [Dispatch>DispatchQueue>init] QUOTE Specify DISPATCH_TARGET_QUEUE_DEFAULT if you want the system to provide a queue that is appropriate for the current object. UNQUOTE What is the difference between passing target queue as 'nil' vs 'DISPATCH_TARGET_QUEUE_DEFAULT' to DispatchQueue init? [Custom Queue][Target Queue concept] [dispatch_set_target_queue] QUOTE The system doesn't allocate threads to the dispatch queue if it has a target queue, unless that target queue is a global concurrent queue. UNQUOTE The system does allocate threads to the custom dispatch queues that have global concurrent queue as the default target. What does that mean? Why does targetting to global concurrent queues mean in that case? [System / GCD Thread Pool] that excutes work items from DispatchQueue: Is this thread pool per queue? or across queues per process? or across processes per device?
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Concurrency Resources
Swift Concurrency Resources: Forums tags: Concurrency The Swift Programming Language > Concurrency documentation Migrating to Swift 6 documentation WWDC 2022 Session 110351 Eliminate data races using Swift Concurrency — This ‘sailing on the sea of concurrency’ talk is a great introduction to the fundamentals. WWDC 2021 Session 10134 Explore structured concurrency in Swift — The table that starts rolling out at around 25:45 is really helpful. Swift Async Algorithms package Swift Concurrency Proposal Index DevForum post Why is flow control important? forums post Dispatch Resources: Forums tags: Dispatch Dispatch documentation — Note that the Swift API and C API, while generally aligned, are different in many details. Make sure you select the right language at the top of the page. Dispatch man pages — While the standard Dispatch documentation is good, you can still find some great tidbits in the man pages. See Reading UNIX Manual Pages. Start by reading dispatch in section 3. WWDC 2015 Session 718 Building Responsive and Efficient Apps with GCD [1] WWDC 2017 Session 706 Modernizing Grand Central Dispatch Usage [1] Avoid Dispatch Global Concurrent Queues forums post Waiting for an Async Result in a Synchronous Function forums post Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" [1] These videos may or may not be available from Apple. If not, the URL should help you locate other sources of this info.
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Background Audio Recording
I have an app that uses background audio recording. From what others say, I have enabled the audio background mode to keep the audio session active, and this worked. But when submitting the app to the app store, the app was rejected because the audio background mode is only supposed to be used for audio playback. How do I create this background mode while following Apple's guidelines?
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Background App Refresh
Hi, I have a couple questions about background app refresh. First, is the function RefreshAppContentsOperation() where to implement code that needs to be run in the background? Second, despite importing BackgroundTasks, I am getting the error "cannot find operationQueue in scope". What can I do to resolve that? Thank you. func scheduleAppRefresh() { let request = BGAppRefreshTaskRequest(identifier: "peaceofmindmentalhealth.RoutineRefresh") // Fetch no earlier than 15 minutes from now. request.earliestBeginDate = Date(timeIntervalSinceNow: 15 * 60) do { try BGTaskScheduler.shared.submit(request) } catch { print("Could not schedule app refresh: \(error)") } } func handleAppRefresh(task: BGAppRefreshTask) { // Schedule a new refresh task. scheduleAppRefresh() // Create an operation that performs the main part of the background task. let operation = RefreshAppContentsOperation() // Provide the background task with an expiration handler that cancels the operation. task.expirationHandler = { operation.cancel() } // Inform the system that the background task is complete // when the operation completes. operation.completionBlock = { task.setTaskCompleted(success: !operation.isCancelled) } // Start the operation. operationQueue.addOperation(operation) } func RefreshAppContentsOperation() -> Operation { }
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BGContinuedProcessingTask register block not called, submit does not throw an error
I implemented BGContinuedProcessingTask in my app and it seems to be working well for everyone except one user (so far) who has reached out to report nothing happens when they tap the Start Processing button. They have an iPhone 12 Pro Max running iOS 26.1. Restarting iPhone does not fix it. When they turn off the background processing feature in the app, it works. In that case my code directly calls the function to start processing instead of waiting for it to be invoked in the register block (or submit catch block). Is this a bug that's possible to occur, maybe device specific? Or have I done something wrong in the implementation? func startProcessingTapped(_ sender: UIButton) { if isBackgroundProcessingEnabled { startBackgroundContinuedProcessing() } else { startProcessing(backgroundTask: nil) } } func startBackgroundContinuedProcessing() { BGTaskScheduler.shared.register(forTaskWithIdentifier: taskIdentifier, using: .main) { @Sendable [weak self] task in guard self != nil else { return } startProcessing(backgroundTask: task as? BGContinuedProcessingTask) } let request = BGContinuedProcessingTaskRequest(identifier: taskIdentifier, title: title, subtitle: subtitle) request.strategy = .fail if BGTaskScheduler.supportedResources.contains(.gpu) { request.requiredResources = .gpu } do { try BGTaskScheduler.shared.submit(request) } catch { startProcessing(backgroundTask: nil) } } func startProcessing(backgroundTask: BGContinuedProcessingTask?) { // FIXME: Never called for this user when isBackgroundProcessingEnabled is true }
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