I have another NSXPC problem, and the problem goes like this NSXPC server implements an interface -(void) callbackWithInfo:(NSDictionary*)log reply:(void (^)(bool))action; The NSXPC client implements a method that will call the interface in a loop and perform a timeout operation. If the server returns to the interface and does not call the action after 1s, the client will perform subsequent operations. The callbackWithInfo interface is then called again, and the cycle continues. client code: The general structure is as follows while(true){ dispatch_semaphore_t semaphore = dispatch_semaphore_create(0); dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ [serverProxy callbackWithInfo:InfoDic reply:^(bool action) { if(flag != NO){ flag = action; } }]; dispatch_semaphore_signal(semaphore); }); if(dispatch_semaphore_wait(semaphore, dispatch_time(DISPATCH_TIME_NOW, self.waitTime *NSEC_PER_MSEC)) != 0){ NSLog(@"flag: %d", flag); } sleep(0.1); } If the action callback is not invoked on the server, the number of FDS on the client increases. As a result, the process cannot open the file, or too much program context information is generated. As a result, the NSXPC interface fails to be invoked. Now I can not operate on the server side, how can the client side implement the code to ensure that the action will not be punished, and the fd will not increase.

I implemented an NSXPC for inter-process data transfer, and the data transferred is NSDictionary. However, a crash occurred during transmission. The corresponding crash logs are as follows Thread 16 Crashed:: Dispatch queue: xpc.test.queue 0 libobjc.A.dylib 0x1945a24d0 objc_retain + 16 1 Foundation 0x1956b7764 -[NSDictionary(NSDictionary) encodeWithCoder:] + 604 2 Foundation 0x195686d9c -[NSXPCEncoder _encodeObject:] + 520 3 Foundation 0x19568c154 _NSXPCSerializationAddInvocationWithOnlyObjectArgumentsArray + 120 4 Foundation 0x19568c000 -[NSXPCEncoder _encodeInvocationObjectArgumentsOnly:count:typeString:selector:isReply:into:] + 212 5 Foundation 0x195684f98 -[NSXPCConnection _sendInvocation:orArguments:count:methodSignature:selector:withProxy:] + 1448 6 Foundation 0x19568d584 -[NSXPCConnection _sendSelector:withProxy:arg1:] + 132 7 Foundation 0x19568d4a8 _NSXPCDistantObjectSimpleMessageSend1 + 68 8 TestDemo 0x1041e9308 0x104184000 + 414472 9 libdispatch.dylib 0x1945565f0 _dispatch_call_block_and_release + 32 10 libdispatch.dylib 0x1945581b4 _dispatch_client_callout + 20 11 libdispatch.dylib 0x19455f8a8 _dispatch_lane_serial_drain + 668 12 libdispatch.dylib 0x194560404 _dispatch_lane_invoke + 392 13 libdispatch.dylib 0x19456ac98 _dispatch_workloop_worker_thread + 648 14 libsystem_pthread.dylib 0x194718360 _pthread_wqthread + 288 15 libsystem_pthread.dylib 0x194717080 start_wqthread + 8 want to know if there is any way to check if NSDictionary data is transferable, NSDictionary data is generated dynamically, and the assignment method used is Info[@ "baseInfo"] = xxx. Is this method necessary to determine whether xxx is not nil?

Hello everyone, With the MacOS update to Venture 13.2, I get the following error message when closing a MacOS app in xCode: [client] No error handler for XPC error: Connection invalid Today I set up a brand new MacOS system which has nothing more installed as except for MacOS Venture 13.2 and xCode 14.2 (14C18). The error already occurs when I start an app that only contains template code. I also started the app without xCode and then closed it through the menu. Then I do not receive an error message. With the Ventura version 13.1 on an AirBook with M1, the problem did not exist. On my Intel iMac, the error causes the iMac to no longer start normally. Thank you very much for your support.

Assume this over-simplified @protocol I'm using for my XPC-service: @protocol MyMinimalProtocol <NSObject> - (void)getStatusWithReply:(void (^ _Nullable)(NSDictionary * _Nonnull))reply; @end The Client side would then NSXPCConnection *connection = [[NSXPCConnection alloc] initWithMachServiceName:myServiceLabel options:NSXPCConnectionPrivileged]; connection.remoteObjectInterface = [NSXPCInterface interfaceWithProtocol:@protocol(MyMinimalProtocol)]; connection.interruptionHandler = ^{ NSLog(@"XPC: connection - interrupted"); }; connection.invalidationHandler = ^{ NSLog(@"XPC: connection - invalidated"); }; [connection resume]; [connection.remoteObjectProxy getStatusWithReply:^(NSDictionary * response) { NSLog(@"XPC service status received - %@", response); }]; So far - so good. My XPC service receives the asynchronous call, schedules it's "status gathering operation" on internal background queue, and returns. Later - when information is available, my XPC service executes the reply-block then, on the remote calling side - I see the log line with the status, as expected. BUT!!! If I add another different code-block argument to the method e.g. @protocol MyMinimalProtocol <NSObject> - (void)getStatusWithReply:(void (^ _Nullable)(NSDictionary * _Nonnull))reply andFailureBlock:(void (^ _Nullable)(NSError * _Nonnull))failureBlock; @end Then all hell breaks loose. Both XPC service and the client crash with hilarious crash reasons I can't decipher. Here's "Client side" caller crash (excerpt - forgive the methods are NOT the simplified ones above) XPC Client(Caller) side crash - excerpt while on the "XPC Service" side, crashes like these: XPC service side crash excerpt I wonder if there's something inherently wrong with having two code-block arguments for an XPC remote method? Another issue. The client XPC calls are asynchronous. They return immediately. The XPC service implementing the remote-call also returns immediately - and it executes the "reply block" far (a minute!) later, on another queue. However, if the XPC service attempts to execute the code-block MORE THAN ONCE, then the client-side code-block is only called ONCE. rest of the executions look benign in the XPC-service side - but never happen on the calling (client) side. Any idea why? can this be overcome? Any thoughts/ideas/references to documentation will be greatly appreciated. I couldn't find any good source on this. Thanks.

I implemented a multithreaded app, but there was a thread-related crash in the app, I don't understand why this happened, the corresponding stack trace is as follows. Thread 15 Crashed:: Dispatch queue: com.apple.root.default-qos 0 libsystem_kernel.dylib 0x1a849ad98 __pthread_kill + 8 1 libsystem_pthread.dylib 0x1a84cfee0 pthread_kill + 288 2 libsystem_c.dylib 0x1a840a340 abort + 168 3 libc++abi.dylib 0x1a848ab08 abort_message + 132 4 libc++abi.dylib 0x1a847a950 demangling_terminate_handler() + 336 5 libobjc.A.dylib 0x1a8370320 _objc_terminate() + 144 6 libc++abi.dylib 0x1a8489ea4 std::__terminate(void (*)()) + 20 7 libc++abi.dylib 0x1a8489e40 std::terminate() + 64 8 libdispatch.dylib 0x1a830c1c8 _dispatch_client_callout + 40 9 libdispatch.dylib 0x1a831da04 _dispatch_root_queue_drain + 680 10 libdispatch.dylib 0x1a831e104 _dispatch_worker_thread2 + 164 11 libsystem_pthread.dylib 0x1a84cc324 _pthread_wqthread + 228 12 libsystem_pthread.dylib 0x1a84cb080 start_wqthread + 8

Hi team, We found that the app reported a lot of crash stacks, and the top of the stack had the libxpc library feature, but we could not find the reason. These issues have only emerged since iOS 16 and are growing, can you provide some clues or provide some solutions? Thanks Crash backtrace can be seen as follows. _ OS Version: 16.6.1 (20G81) Report Version: 104 SDK start time: 2023-09-20 18:42:40 RDM SDK Version: 2.7.27.1 RDM user id : 119902290602 RDM DeviceId: 0DB20076-F323-468F-9EEC-080B77A00E05 RDM APP KEY: 7c35edbf90 Last Exception : 0 libxpc.dylib 0x000000020a019e98 __xpc_dictionary_insert + 96 1 libxpc.dylib 0x000000020a019e84 __xpc_dictionary_insert + 76 2 libxpc.dylib 0x000000020a01b944 __xpc_dictionary_deserialize_apply + 68 3 libxpc.dylib 0x000000020a01b8cc __xpc_dictionary_apply_wire_f + 136 4 libxpc.dylib 0x000000020a018da4 __xpc_dictionary_deserialize + 108 5 libxpc.dylib 0x000000020a00cdf4 __xpc_array_deserialize + 204 6 libxpc.dylib 0x000000020a01b9ec __xpc_dictionary_unpack_value + 120 7 libxpc.dylib 0x000000020a01bbf0 __xpc_dictionary_unpack_value_and_vend + 28 8 libxpc.dylib 0x000000020a01a4c4 __xpc_dictionary_look_up + 156 9 libxpc.dylib 0x000000020a01b094 _xpc_dictionary_get_array + 20 10 libdns_services.dylib 0x000000020a0b9a28 ____dnssd_client_connection_block_invoke_2 + 320 11 libxpc.dylib 0x000000020a015af0 __xpc_connection_call_event_handler + 152 12 libxpc.dylib 0x000000020a015f20 __xpc_connection_mach_event + 992 13 libdispatch.dylib 0x00000001b1657f6c __dispatch_client_callout4 + 20 14 libdispatch.dylib 0x00000001b16746ec __dispatch_mach_msg_invoke + 468 15 libdispatch.dylib 0x00000001b165f40c __dispatch_lane_serial_drain + 372 16 libdispatch.dylib 0x00000001b1675438 __dispatch_mach_invoke + 448 17 libdispatch.dylib 0x00000001b165f40c __dispatch_lane_serial_drain + 372 18 libdispatch.dylib 0x00000001b16600a4 __dispatch_lane_invoke + 384 19 libdispatch.dylib 0x00000001b166acdc __dispatch_workloop_worker_thread + 648 20 libsystem_pthread.dylib 0x0000000209fc1ddc __pthread_wqthread + 288 Exception Type: SIGSEGV SEGV_ACCERR Exception Codes: fault addr: 0x0000000000000036 Crashed Thread: 7 _

I randomly get this crash in my webview application when loading data. There is no pattern to it, it can happen in all areas where images are being loaded into vram. Here is the error: 2023-09-16 19:57:55.404378+0200 Bluelife[3284:194440] [Process x10d004350 - [PID=3445] WebProcessProxy: :didClose: (web process 0 crash) 2023-09-16 19:57:55.404500+0200 Bluelife3284:194440] [Process] 0x10d004350 - [PID=3445 WebProcessProxy::processDidTerminate0rFailedToLaunch: reason=Crash 2023-09-16 19:57:55.404579+0200 Bluelife[3284:194440] [ProcessSuspension] 0x10c01dfe - ProcessAssertion: Failed to acquire RBS Background assertion 'XPCConnectionTerminationWatchdog' for process because PID 0 is invalid 2023-09-16 19:57:55.410251+0200 Bluelife[3284:194440] [Process] 0x130856218 - [pageProxyID=14, webPageID=15, PID=3445] WebPageProxy: :processDidTerminate: (pid 3445), reason=Crash 2023-09-16 19:57:55.411392+0200 Bluelife[3284:211863] [ProcessSuspension] 0x10c01dfe - ProcessAssertion::acquireSync Failed to acquire RBS assertion 'XPCConnectionTerminationWatchdog' for process with PID=0, error: (null) 2023-09-16 19:57:55.424321+0200 Bluelife[3284:194440] [Loading] 0x130856218 - [pageProxID=14, webPageID=15, PID=3445] WebPageProxy::dispatchProcessDidTerminate: reason=Crash

Hello, I encountered such a problem, the scenario is like this: I have a launchctl startup daemon called xpcserver.app, which uses NSXPC to start an xpc Server. There is a Client program that links to the nsxpc service of this xpcserver.app, and when I establish the connection, I call an interface implemented by xpcserver named setName:(nsstring*)name. I was sure that my xpcserver implemented the corresponding interface, but when the client called the interface to pass the value, it triggered the error "unrecognized selector sent to instance". When I restarted the client, the call to the interface successfully implemented the function. May I ask why? Using the NSXPC started service, hope to solve, thank you

I randomly get this crash in my webview application when loading data. There is no pattern to it, it can happen in all areas where images are being loaded into vram.

I have a NSXPCListener in an app and like to connect to from a command line tool. I can’t get it to work so I wonder if it is not supported of if I miss something. Any help is greatly appreciated.

Hello, I'm struggling to understand how I can use NSXPC API to communicate between two processes on iOS. The problem which I want to solve is how to pass some information from VPN tunnel to the VPN app. I'm looking at the XPC documentation and for iOS I can create NSXPCListener only with the following functions: service() anonymous() Both return NSXPCListener instance. But the question remains, how to connect to such an instance? In NSXPConnection API I see only one option for iOS: init(listenerEndpoint: NSXPCListenerEndpoint) Other constructors accepting serviceName or machServiceName are available only form macOS. I feel like the problem of communicating between two processes should be easy, but surprisingly I did find it quite difficult on iOS. Can you please advice if this is a proper API for my use case? Or maybe is there some better one, which I'm not aware of? If this is a proper API, how should I create a connection between two apps? How to pass a listener from one process to the other?

I have a regular GUI-based app that communicates with an Endpoint System Extension installed by another app. Both the GUI app and Endpoint System Extension have the same Team ID and are part of the same App Groups. But I still need to do one of the following to the GUI-based app to allow it to communicate with the Endpoint System Extension over XPC: Disable the sandbox Add com.apple.security.temporary-exception.mach-lookup.global-name to entitlements For some reason I thought there was another way to resolve this. Am I missing anything? (My goal is to allow an app distributed through the Mac App Store to communicate with my Endpoint System Extension if it exists, and I am worried about the "temporary-exception" entitlement needed to support this.)

Hi! First time using XPC on a Mac app, and I'm stuck on a problem I can't understand. I have an app with multiple frameworks, and I'm adding an XPC service to one of the pre-existing frameworks. Right now the service is just the template that uppercases a string. I took all the necessary steps, I believe (adding the service as a target dependency, and copying it to the XPC Services folder). However, when I run it in Debug mode, I always get: Error Domain=NSCocoaErrorDomain Code=4099 "The connection to service named <fully qualified service bundle ID> was invalidated: failed at lookup with error 3 - No such process." I also tested on a different, pre-existing framework, and the same thing happens. Here's the weird parts: if I create a new framework and follow exactly the same steps, it works. I've compare the build settings between both frameworks and everything seems similar. And if I run in Release mode, the original service on the problematic framework also works! If I create a project with similar setup (app + framework with service inside it), it also works. Looking at Console.app, I don't see anything that explains what's happening, but I may be filtering for the wrong thing. Any help on why this fails specifically on my pre-existing frameworks and only on Debug mode is much appreciated. :) Thank you, Miguel Arroz

Hello, I'm trying to get my app to communicate with a FinderSync extension using XPC. In my app, I run the listener: _xpcListener = [[NSXPCListener alloc] initWithMachServiceName:_serviceName]; _xpcListener.delegate = self; [_xpcListener resume]; Where _serviceName="a.b.c.d.e.f" In Info.plist of the app bundle, I have: keyMachServices/key dict keya.b.c.d.e.f/key true/ /dict In the FinderSync ext, I try to connect to the XPC service: _xpcConnection = [[NSXPCConnection alloc] initWithMachServiceName:_serviceName options:0]; ... [_xpcConnection resume]; It works in debug, but not when the app is installed. In this case, _xpcConnection.invalidationHandler is called. The FinderSync ext belongs to the app bundle. The .entitlements of the App: ?xml version="1.0" encoding="UTF-8"? !DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "..." plist version="1.0" dict keycom.apple.security.application-groups/key array stringa.b.c.d.e/string /array /dict /plist The .entitlements of the FinderSync: ?xml version="1.0" encoding="UTF-8"? !DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "..." plist version="1.0" dict keycom.apple.security.app-sandbox/key true/ keycom.apple.security.application-groups/key array stringa.b.c.d.e/string /array /dict /plist The app is notorized: % spctl --assess -vvvv /Applications/myApp.app                 /Applications/myApp.app: accepted source=Notarized Developer ID origin=Developer ID Application: ... In the Console, just after the start of the listener, there is this error (3 times) for myApp process: Trust evaluate failure: [leaf TemporalValidity] So I checked its certificates, but they are valid: % codesign -dvvvv --extract-certificates /Applications/myApp.app % openssl x509 -inform DER -in codesign0 -text ... Validity       Not Before: Jun 22 11:59:25 2020 GMT       Not After : Jun 23 11:59:25 2025 GMT .. % openssl x509 -inform DER -in codesign1 -text ... Validity       Not Before: Feb 1 22:12:15 2012 GMT       Not After : Feb 1 22:12:15 2027 GMT ... % openssl x509 -inform DER -in codesign2 -text ... Validity       Not Before: Apr 25 21:40:36 2006 GMT       Not After : Feb 9 21:40:36 2035 GMT ... The computer date is Ok: % date Thu Apr 8 09:20:44 CEST 2021 In the console, there is also this error for tccd process: Prompting policy for hardened runtime; service: kTCCServiceAppleEvents requires entitlement com.apple.security.automation.apple-events but it is missing for accessing={identifier=a.b.c.d.e, pid=12245, auid=501, euid=501, binary_path=/Applications/myApp.app/Contents/PlugIns/Extension.appex/Contents/MacOS/Extension}, requesting={identifier=com.apple.appleeventsd, pid=328, auid=55, euid=55, binary_path=/System/Library/CoreServices/appleeventsd}, I tried to add this com.apple.security.automation.apple-events entitlement to App and ext, but it didn't fix the problem. How can I debug this issue? Thank you.

We have 2 process in our macOS application Daemon process written in golang Swift application Currently, the communication between both the process are done with Unix domain socket. However, we are seeing significant amount of delay when large amount of data communication. We are looking for some faster communication. Probably XPC is the answer. But not sure how to use XPC between two process which are written in different language. Any sample code would be great help.

We see warnings like this logged by our processes using XPC: (Foundation) [com.apple.runtime-issues:Foundation] *** -[NSXPCDecoder validateAllowedClass:forKey:]: NSSecureCoding allowed classes list contains [NSObject class], which bypasses security by allowing any Objective-C class to be implicitly decoded. Consider reducing the scope of allowed classes during decoding by listing only the classes you expect to decode, or a more specific base class than NSObject. This will become an error in the future. Allowed class list: {( "'NSObject' (0x7ff844ee0d88) [/usr/lib]" )} As far as we can see, there is no explicit NSObject in allowed classes for any XPC connection. Where does this list and NSObject come from?

Hello! I'm new here, and probably this will sound weird but, I'm trying to write a C++ program using an XPC service to attempt to communicate with a macOS app I'm developing in Swift. At the macOS app side I think I'm successfully registering and connecting to the service, as launchd reports the following in its log: 2023-05-31 17:20:21.898621 (pid/15637 [On Air]) <Notice>: Service stub created for com.ruieduardolopes.onaird-join At the C++ side I'm trying to get a simple example working, as follows, but currently without any success... #include <xpc/xpc.h> int main(int argc, const char* argv[]) { xpc_connection_t conn = xpc_connection_create_mach_service("com.ruieduardolopes.onaird.join", NULL, 0); xpc_object_t message = xpc_dictionary_create(NULL, NULL, 0); xpc_connection_set_event_handler(conn, ^(xpc_object_t object) {}); xpc_connection_resume(conn); xpc_dictionary_set_string(message, "SS", "AAAAAA\n"); xpc_connection_send_message_with_reply(conn, message, dispatch_get_main_queue(), ^(xpc_object_t object) {}); return (EXIT_SUCCESS); } I get the following error in the logs: 2023-05-31 17:27:45.636894 (system/com.ruieduardolopes.onaird) <Notice>: internal event: WILL_SPAWN, code = 0 2023-05-31 17:27:45.636903 (system/com.ruieduardolopes.onaird) <Notice>: service state: spawn scheduled 2023-05-31 17:27:45.636904 (system/com.ruieduardolopes.onaird) <Notice>: service state: spawning 2023-05-31 17:27:45.637017 (system/com.ruieduardolopes.onaird) <Notice>: launching: ipc (mach) 2023-05-31 17:27:45.637256 (system/com.ruieduardolopes.onaird [15908]) <Notice>: xpcproxy spawned with pid 15908 2023-05-31 17:27:45.637264 (system/com.ruieduardolopes.onaird [15908]) <Notice>: internal event: SPAWNED, code = 0 2023-05-31 17:27:45.637265 (system/com.ruieduardolopes.onaird [15908]) <Notice>: service state: xpcproxy 2023-05-31 17:27:45.637269 (system/com.ruieduardolopes.onaird [15908]) <Notice>: internal event: SOURCE_ATTACH, code = 0 2023-05-31 17:27:45.648927 (system/com.ruieduardolopes.onaird [15908]) <Notice>: service state: running 2023-05-31 17:27:45.648940 (system/com.ruieduardolopes.onaird [15908]) <Notice>: internal event: INIT, code = 0 2023-05-31 17:27:45.648948 (system/com.ruieduardolopes.onaird [15908]) <Notice>: Successfully spawned onaird-join[15908] because ipc (mach) 2023-05-31 17:27:45.687251 (system/com.ruieduardolopes.onaird [15908]) <Notice>: exited due to SIGTRAP | sent by exc handler[15908] 2023-05-31 17:27:45.687261 (system/com.ruieduardolopes.onaird [15908]) <Notice>: service has crashed 1 times in a row 2023-05-31 17:27:45.687263 (system/com.ruieduardolopes.onaird [15908]) <Notice>: service state: exited 2023-05-31 17:27:45.687267 (system/com.ruieduardolopes.onaird [15908]) <Notice>: internal event: EXITED, code = 0 2023-05-31 17:27:45.687269 (system) <Notice>: service inactive: com.ruieduardolopes.onaird 2023-05-31 17:27:45.687281 (system/com.ruieduardolopes.onaird [15908]) <Notice>: service state: not running 2023-05-31 17:27:45.687290 (system/com.ruieduardolopes.onaird) <Notice>: Service only ran for 0 seconds. Pushing respawn out by 10 seconds. 2023-05-31 17:27:45.687339 (system/com.ruieduardolopes.onaird) <Notice>: internal event: WILL_SPAWN, code = 0 2023-05-31 17:27:45.687343 (system/com.ruieduardolopes.onaird) <Notice>: service state: spawn scheduled 2023-05-31 17:27:45.687344 (system/com.ruieduardolopes.onaird) <Notice>: service throttled by 10 seconds The plist file I'm currently loading to /Library/LaunchDaemons is as follows: <?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.ruieduardolopes.onaird</string> <key>Program</key> <string>PATH_TO_ONAIR_JOIN_XPC_SERVICE_BINARY</string> <key>BuildMachineOSBuild</key> <string>22C65</string> <key>CFBundleDevelopmentRegion</key> <string>en</string> <key>CFBundleDisplayName</key> <string>onaird-join</string> <key>CFBundleExecutable</key> <string>onaird-join</string> <key>CFBundleIdentifier</key> <string>com.ruieduardolopes.onaird-join</string> <key>CFBundleInfoDictionaryVersion</key> <string>6.0</string> <key>CFBundleName</key> <string>onaird-join</string> <key>CFBundlePackageType</key> <string>XPC!</string> <key>CFBundleShortVersionString</key> <string>1.0</string> <key>CFBundleSupportedPlatforms</key> <array> <string>MacOSX</string> </array> <key>CFBundleVersion</key> <string>1</string> <key>DTCompiler</key> <string>com.apple.compilers.llvm.clang.1_0</string> <key>DTPlatformBuild</key> <string></string> <key>DTPlatformName</key> <string>macosx</string> <key>DTPlatformVersion</key> <string>13.3</string> <key>DTSDKBuild</key> <string>22E245</string> <key>DTSDKName</key> <string>macosx13.3</string> <key>DTXcode</key> <string>1430</string> <key>DTXcodeBuild</key> <string>14E222b</string> <key>LSMinimumSystemVersion</key> <string>13.1</string> <key>MachServices</key> <dict> <key>com.ruieduardolopes.onaird.join</key> <true/> </dict> <key>XPCService</key> <dict> <key>ServiceType</key> <string>Application</string> </dict> </dict> </plist> Can anybody help me? Thanks in advance, Rui

I am working as an iOS Developer since 2 years. I am getting log on console like: [MADService] Client XPC connection invalidated sometimes. I am unable to get when and for what reason i am getting this. need some help. Thank you

I need launchd to execute a script when a certain kind of usb device is connected. Specifically, an iOS device.is this possible? If so, what should the launchd plist look like?

Hello,Technical Note TN2151 describes the 0xdead10cc exception:&gt; The exception code 0xdead10cc indicates that an application has been terminated by the OS because it held on to a file lock or sqlite database lock during suspension. If your application is performing operations on a locked file or sqlite database at suspension time, it must request additional background execution time to complete those operations and relinquish the lock before suspending.This is all pretty clear. After the additional background execution time has expired, all SQLite accesses that create a lock create a risk for sudden termination. An application which wants to avoid 0xdead10cc has thus to actively prevent such accesses... until the application wakes up from the suspended state. My questions are all about the end of this critical lapse of time in the app's life cycle.Eventually, the application may become active, and this clearly marks the end of the 0xdead10cc danger. This moment is notified by UIApplicationWillEnterForegroundNotification. After this notification is posted, it becomes possible again to access an SQLite database without risking any 0xdead10cc exception, until the next UIApplicationDidEnterBackgroundNotification, and the next notification of additional background execution time expiration.But what about cases when the application leaves the suspended state and reenters the background state? This may happen due to the various background modes supported by iOS.First question: Is there one way to be notified of this transition from suspended to background state, regardless of the reason for this background wake-up (core location, VoIP, background fetch, etc.) ?Second question: Is it then possible to start another request for additional background execution time and be reliably notified when accessing the SQLite database creates a 0xdead10cc threat again?Third question: do you have any other advice regarding 0xdead10cc prevention?For the context, I'm the author of GRDB, and I'm looking for a way to package 0xdead10cc prevention in a way that reduces to a minimum the amount of code users have to write in order to protect their app from this exception. Ideally, it would be reduced to a simple boolean flag targetted at users who store their database in an App Group container.Thank you very much!