Processes & Concurrency

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Discover how the operating system manages multiple applications and processes simultaneously, ensuring smooth multitasking performance.

Concurrency Documentation

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ExtensionKit and iOS 26
It looks like ExtensionKit (and ExtensionFoundation) is fully available on iOS 26 but there is no mention about this in WWDC. From my testing, it seems as of beta 1, ExtensionKit allows the app from one dev team to launch extension provided by another dev team. Before we start building on this, can someone from Apple help confirm this is the intentional behavior and not just beta 1 thing?
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Jun ’25
ExtensionKit & ExtensionFoundation process lifecycle
An XPC service’s process has a system-managed lifecycle: the process is launched on-demand when another process tries to connect to it, and the system can decide to kill it when system resources are low. XPC services can tell the system when they shouldn’t be killed using xpc_transaction_begin/end. Do extensions created with ExtensionFoundation and/or ExtensionKit have the same behavior?
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126
Jul ’25
Need to start the Mac application automatically
I am developing the application in Mac. My requirement is to start the application automatically when user login. I have tried adding the plist file in launch agents, But it doesn't achieve my requirement. Please find the code added in the launch agents <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>Label</key> <string>com.sftk.secure</string> <key>ProgramArguments</key> <array> <string>/Applications/Testing.app/Contents/MacOS/Testing</string> </array> <key>RunAtLoad</key> <true/> <key>KeepAlive</key> <false/> </dict> </plist> I have tried by adding manually in the setting, but it was opened sometimes and closed suddenly. On open manually it works. Please provide a solution to start the application automatically on system starts
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Jul ’25
Running external binaries from Swift Package (TTS engine): Operation not permitted from Xcode app
Hi everyone, We’re developing a macOS SwiftUI app that uses a local Swift Package (CasSherpaCore) to invoke an external compiled binary (sherpa-onnx-offline-tts) for text-to-speech synthesis using system calls. The package works flawlessly when tested from terminal or via a lightweight test C program. However, when we invoke it from a SwiftUI app (even with Full Disk Access granted to Xcode and Terminal), we consistently get the error: sh: /Users/xxxxxxxxxxx/SherpaONNX/sherpa-onnx/build/bin/sherpa-onnx-offline-tts: Operation not permitted We’ve tried: Granting Full Disk Access to Xcode and Terminal. Removing the quarantine flag with xattr -d com.apple.quarantine. Setting executable permission via chmod +x. Using both system() and Process in C and Swift contexts. Testing within a Swift Package that’s integrated into the app as a local dependency. Running the command manually from terminal (works perfectly). It appears that macOS (or Xcode’s runtime sandbox) is restricting execution of binaries from certain locations or contexts when launched via system() inside the app. Questions: Is there a specific entitlement or configuration that allows execution of local binaries from a SwiftUI macOS app? Is this related to System Integrity Protection (SIP) or a hardened runtime limitation? Are there best practices or alternative approaches to safely execute local TTS binaries from within a Swift app? Any help would be deeply appreciated. This is a core feature in our project and we’re stuck at this point. Thank you so much in advance!
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Jul ’25
When using SMAppService to register a daemon, is it possible to let the authorization dialog show on behalf of my application? e.g.: showing the app name, custom icon and prompt, etc..
My app is for personal use currently, so distribution won't be a problem. It registers a privileged helper using SMAppService, and I was wondering whether there is a way to customize the authorization dialog that the system presents to the user.
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Jul ’25
SMAppService daemon not running
My app uses SMAppService to register a privileged helper, the helper registers without errors, and can be seen in System Settings. I can get a connection to the service and a remote object proxy, but the helper process cannot be found in Activity Monitor and the calls to the proxy functions seem to always fail without showing any specific errors. What could be causing this situation?
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210
Jul ’25
Does BGAppRefreshTask require an internet connection?
Basically the title. I am trying to implement a local notification to trigger, regardless of internet connection, around 3-5pm if a certain array in the app is not empty to get the user to sync unsaved work with the cloud. I wanted to used the BGAppRefreshTask as I saw it was lightweight and quick for just posting a banner notification but after inspecting it in the console, it looks like it needs internet connection to trigger. Is this the case or am I doing something wrong? Should I be using the BGProcessingTask instead?
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Jul ’25
Alternatives to com.apple.security.temporary-exception.apple-events: com.apple.Terminal ?
Hello 👋 Our team added com.apple.security.temporary-exception.apple-events: com.apple.Terminal recently to our Mac app to be able to tell the terminal to execute a specific command line automatically for the user when clicking a button but we've been rejected during review because of this entitlement so for now we've deleted it and deleted the associated feature. It concerns the following feature (see attachment). Context: Among other things the application enable to review pull request changes (remote) and we would like a button to automatically clone the pull request on disk when user click a button. We would like to use terminal for security reason as when cloning using git command we need ssh keys or other credential and there's no reason (rather than technical ones) that the user provide us such private information that is stored in the ~/.ssh. We prefer think the other way around and tell the user what to execute instead (no credentials involved or shared). We referred to: https://developer.apple.com/library/archive/documentation/Miscellaneous/Reference/EntitlementKeyReference/Chapters/AppSandboxTemporaryExceptionEntitlements.html I admit it's unclear for me if this will imply a 100% rejection or if these entitlements are deprecated. Is "com.apple.security.temporary-exception.apple-events: com.apple.Terminal" an entitlement that is reserved for special Apple partners ? Is it an entitlement that we should demonstrate usage first ? Or should we completely remove the feature if we distribute through the App Store ? Is Apple advice for other APIs to develop such features (execute command line for the user) when distributing through the App Store ? As said we've disabled the feature for now. Thank you in advance for those who will take time to answer this,
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Jul ’25
System Network Extension XPC with LaunchAgent
I've discovered that a system network extension can communicate with a LaunchDaemon (loaded using SMAppService) over XPC, provided that the XPC service name begins with the team ID. If I move the launchd daemon plist to Contents/Library/LaunchAgents and swap the SMAppService.daemon calls to SMAppService.agent calls, and remove the .privileged option to NSXPCConnection, the system extension receives "Couldn't communicate with a helper application" as an error when trying to reach the LaunchAgent advertised service. Is this limitation by design? I imagine it is, but wanted to check before I spent any more time on it.
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Jul ’25
Reliable 30-minute background data fetching for safety-critical monitoring app?
I'm developing a safety-critical monitoring app that needs to fetch data from government APIs every 30 minutes and trigger emergency audio alerts for threshold violations. The app must work reliably in background since users depend on it for safety alerts even while sleeping. Main Challenge: iOS background limitations seem to prevent consistent 30-minute intervals. Standard BGTaskScheduler and timers get suspended after a few minutes in background. Question: What's the most reliable approach to ensure consistent 30-minute background monitoring for a safety-critical app where missed alerts could have serious consequences? Are there special entitlements or frameworks for emergency/safety applications? The app needs to function like an alarm clock - working reliably even when backgrounded with emergency audio override capabilities.
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Jul ’25
dispatch_main and main thread local variables
Hello, We're seeing some strange crashes and noticed the following. It's unclear if related or not. The contract for xpc_main, which internally calls dispatch_main, is This function never returns. and they are appropriately peppered with __attribute__((__noreturn__)). Documentation states: This function “parks” the main thread and waits for blocks to be submitted to the main queue. However, internally, dispatch_main calls pthread_exit. pthread_exit's documentation states that: After a thread has terminated, the result of access to local (auto) variables of the thread is undefined. Thus, references to local variables of the exiting thread should not be used for the pthread_exit() value_ptr parameter value. I'd say the two contracts of This function never returns. and thread exiting with its storage released are diametrically opposed and can create nuanced issues. Consider the following code: struct asd { int a; }; struct asd* ptr; void fff(void* ctx) { while(true) { printf("%d\n", ptr->a); ptr->a = (ptr->a + 1); usleep(100000); } } int main(int argc, const char * argv[]) { struct asd zxc; zxc.a = 1; ptr = &zxc; dispatch_async_f(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), NULL, fff); dispatch_main(); return 0; } This is a ***** over-simplification of the code we have, but in the same "spirit". We have a C++ object that is created on the stack and exposes one of its members as a global pointer, with the assumption that it would never release. What I understand from This function never returns is that the calling thread remains dormant and its stack remains alive. What I understand from pthread_exit is that the thread is killed (this is verified with a debugger attached) and its stack storage is released. Another thing that is throwing me off is that no sanitizer that is provided by clang/Xcode catches this issue. I don't see any special handling of the internal pthread_t in libdispatch to keep the stack storage alive. Our code is more complex, but can be solved by allocating the initial object on the heap, rather than on the stack. But still I would like to understand if this is the expected behavior. Perhaps my preconception of __attribute__((__noreturn__)) is wrong, and accessing stack variables post call to a __attribute__((__noreturn__)) function is UB? Thanks
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Jul ’25
Expected behavior from apps when MacOS goes to sleep
Every time macOS goes to sleep the processes get suspended which is expected. But during the sleep period, all processes keep coming back and they all get a small execution window where they make some n/w requests. Regardless of what power settings i have. It also does not matter whether my app is a daemon or not Is there any way that i can disable this so that when system is in sleep, it stays in suspended, no intermittent execution window? I have tried disabling Wake for network access setting but processes still keep getting intermittent execution window. Is there any way that i can prevent my app from coming back while in sleep. I don't want my app to get execution window, perform some executions and then get suspended not knowing when it will get execution window again?
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Aug ’25
App is getting terminated by OS even after calling BG task expiration
The application is placed into the idle state. Subsequently, the device enters a sleep state. While the device is in sleep, App start background task within the application successfully receives its expirationHandler callback. App received the expiration callback and App called the end BGtask OS did not released the Assertion. Resulting in App getting terminated by the OS for exceeding the BG task Apple Feedback- FB19192371
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Aug ’25
BGTaskScheduler fails to match unique identifiers to a registered wildcard handler for BGContinuedProcessingTask
Testing Environment: iOS Version: 26.0 Beta 7 Xcode Version: 17.0 Beta 6 Device: iPhone 16 Pro Description: We are implementing the new BGContinuedProcessingTask API and are using the wildcard identifier notation as described in the official documentation. Our Info.plist is correctly configured with a permitted identifier pattern, such as com.our-bundle.export.*. We then register a single launch handler for this exact wildcard pattern. We are performing this registration within a UIViewController, which is a supported pattern as BGContinuedProcessingTask is explicitly exempt from the "register before applicationDidFinishLaunching" requirement, according to the BGTaskScheduler.h header file. The register method correctly returns true, indicating the registration was successful. However, when we then try to submit a task with a unique identifier that matches this pattern (e.g., com.our-bundle.export.UUID), the BGTaskScheduler.shared.submit() call throws an NSInternalInconsistencyException and terminates the app. The error reason is: 'No launch handler registered for task with identifier com.our-bundle.export.UUID'. This indicates that the system is not correctly matching the specific, unique identifier from the submit call to the registered wildcard pattern handler. This behavior contradicts the official documentation. Steps to Reproduce: Create a new Xcode project. In Signing & Capabilities, add "Background Modes" (with "Background processing" checked) and "Background GPU Access". Add a permitted identifier (e.g., "com.company.test.*") to BGTaskSchedulerPermittedIdentifiers in Info.plist. In a UIViewController's viewDidLoad, register a handler for the wildcard pattern. Check that the register method returns true. Immediately after, try to submit a BGContinuedProcessingTaskRequest with a unique identifier that matches the pattern. Expected Results: The submit call should succeed without crashing, and the task should be scheduled. Actual Results: The app crashes immediately upon calling submit(). The console shows an uncaught NSInternalInconsistencyException with the reason: 'No launch handler registered for task with identifier com.company.test.UUID'. Workaround: The issue can be bypassed if we register a new handler for each unique identifier immediately before submitting a request with that same unique identifier. This strongly suggests the bug is in the system's wildcard pattern-matching logic.
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3w
Mac: Best way to distinguish native app process and script process spawned from executable (e.g. python node) through process_id
I'm working on a Mac app that receives a process ID via NSXPCConnection, and I'm trying to figure out the best way to determine whether that process is a native macOS app like Safari—with bundles and all—or just a script launched by something like Node or Python. The executable is signed with a Team ID using codesign. I was thinking about getting the executable's path as one way to handle it, but I’m wondering if there’s a more reliable method than relying on the folder structure.
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3w
LLDB Cannot Load ODBC Driver Due to Sandbox Restrictions - How to Debug
I'm developing a macOS console application that uses ODBC to connect to PostgreSQL. The application works fine when run normally, but fails to load the ODBC driver when debugging with LLDB(under root works fine as well). Error Details When running the application through LLDB, I get this sandbox denial in the system log (via log stream): Error 0x0 0 0 kernel: (Sandbox) Sandbox: logd_helper(587) deny(1) file-read-data /opt/homebrew/lib/psqlodbcw.so The application cannot access the PostgreSQL ODBC driver located at /opt/homebrew/lib/psqlodbcw.so(also tried copy to /usr/local/lib/...). Environment macOS Version: Latest Sequoia LLDB: Using LLDB from Xcode 16.3 (/Applications/Xcode16.3.app/Contents/Developer/usr/bin/lldb) ODBC Driver: PostgreSQL ODBC driver installed via Homebrew Code Signing: Application is signed with Apple Development certificate What is the recommended approach for debugging applications that need to load dynamic libraries? Are there specific entitlements or configurations that would allow LLDB to access ODBC drivers during debugging sessions? Any guidance would be greatly appreciated. Thank you for any assistance!
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1w
BGContinuedProcessingTask Notification Error
Hello im creating an expo module using this new API, but the problem i found currently testing this functionality is that when the task fails, the notification error doesn't go away and is always showing the failed task notification even if i start a new task and complete that one. I want to implement this module into the production app but i feel like having always the notification error might confuse our users or find it a bit bothersome. Is there a way for the users to remove this notification? Best regards!
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1w
Stay connected to Medical BLE device in background
I work for a large medical device company. We have a 1st party BLE enabled medical device that must be very battery efficient. To this end, if a connection is lost, the BLE radio is powered down after 60 seconds and will only turn back on when a physical button on the device is pressed. I've been tasked with connecting to the device, staying connected to the device, and being able to retrieve data from the device upon a timed action. For instance, this could include a data read and transmission while they sleep. The key part of this is staying reliably connected for extended periods of time. This is a BYOD setup, and we cannot control power profiles. I would very much appreciate any information, recommendations, and/or insights into solving this problem. Thanks!
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1w
Privileged helper without SMJobBless
To establish a privileged helper daemon from a command line app to handle actions requiring root privileges I still use the old way of SMJobBless. But this is deprecated since OSX 10.13 and I want to finally update it to the new way using SMAppService. As I'm concerned with securing it against malicious exploits, do you have a recommended up-to-date implementation in Objective-C establishing a privileged helper and verifying it is only used by my signed app? I've seen the suggestion in the documentation to use SMAppService, but couldn't find a good implementation covering security aspects. My old implementation in brief is as follows: bool runJobBless () { // check if already installed NSFileManager* filemgr = [NSFileManager defaultManager]; if ([filemgr fileExistsAtPath:@"/Library/PrivilegedHelperTools/com.company.Helper"] && [filemgr fileExistsAtPath:@"/Library/LaunchDaemons/com.company.Helper.plist"]) { // check helper version to match the client // ... return true; } // create authorization reference AuthorizationRef authRef; OSStatus status = AuthorizationCreate (NULL, kAuthorizationEmptyEnvironment, kAuthorizationFlagDefaults, &authRef); if (status != errAuthorizationSuccess) return false; // obtain rights to install privileged helper AuthorizationItem authItem = { kSMRightBlessPrivilegedHelper, 0, NULL, 0 }; AuthorizationRights authRights = { 1, &authItem }; AuthorizationFlags flags = kAuthorizationFlagDefaults | kAuthorizationFlagInteractionAllowed | kAuthorizationFlagPreAuthorize | kAuthorizationFlagExtendRights; status = AuthorizationCopyRights (authRef, &authRights, kAuthorizationEmptyEnvironment, flags, NULL); if (status != errAuthorizationSuccess) return false; // SMJobBless does it all: verify helper against app and vice-versa, place and load embedded launchd.plist in /Library/LaunchDaemons, place executable in /Library/PrivilegedHelperTools CFErrorRef cfError; if (!SMJobBless (kSMDomainSystemLaunchd, (CFStringRef)@"com.company.Helper", authRef, &cfError)) { // check helper version to match the client // ... return true; } else { CFBridgingRelease (cfError); return false; } } void connectToHelper () { // connect to helper via XPC NSXPCConnection* c = [[NSXPCConnection alloc] initWithMachServiceName:@"com.company.Helper.mach" options:NSXPCConnectionPrivileged]; c.remoteObjectInterface = [NSXPCInterface interfaceWithProtocol:@protocol (SilentInstallHelperProtocol)]; [c resume]; // call function on helper and wait for completion dispatch_semaphore_t semaphore = dispatch_semaphore_create (0); [[c remoteObjectProxy] callFunction:^() { dispatch_semaphore_signal (semaphore); }]; dispatch_semaphore_wait (semaphore, dispatch_time (DISPATCH_TIME_NOW, 10 * NSEC_PER_SEC)); dispatch_release (semaphore); [c invalidate]; [c release]; }
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Are iPad apps that are closed with the red traffic light prevented from running background tasks?
In iOS Background Execution limits, I see this: When the user ‘force quits’ an app by swiping up in the multitasking UI, iOS interprets that to mean that the user doesn’t want the app running at all. iOS also sets a flag that prevents the app from being launched in the background. That flag gets cleared when the user next launches the app manually. However, I see that when I close an app on iPadOS 26 with the red X, the app doesn't appear in the multitasking UI. So are they treated as force closes and prevented from running background tasks?
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