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Swapping the `objectAtIndex:` method of `__NSArrayM` using `method_exchangeImplementations` will lead to continuous memory growth.
After swapping the -objectAtIndex: method using method_exchangeImplementations, it will cause continuous memory growth. Connect the iPhone and run the provided project. Continuously tap the iPhone screen. Observe Memory; it will keep growing. Sample code
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Jul ’25
jmp_buf layout for Apple Silicon
Greetings! I am actively working on porting x64 code to Apple Silicon now that the time is nigh and part of the fundamentals of our software is a coroutine library for handling cooperative multitasking of GUI operations on the main thread. I was hoping to get the locations of the stack pointer and frame pointer in jmp_buf so, after setjmp() can redirect them to the primary handling routines in our coroutine library that handles the cooperative scheduling (which replaced and ported the old classic MP routines) which worked for PowerPC, i386 and x64. Any thoughts on where in the jmp_buf these might be located? I didn't see anything in the XNU open source. Any advice would be much obliged instead of having to dive in and re-implement these routines in assembly myself!
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Aug ’25
Overriding global new and delete is not working.
We developing Native App with C++17 for iOS. We override global new and delete operators. This App deallocate all allocated memories correctly by Run on Xcode (Command + R), but exception occurs launch from xcrun or App icon on iPhone. I debugged the exception. Overriding new operation was called correctly, but overriding delete operation was not called. The default delete was called. I'm not sure why is that. STEPS TO REPRODUCE Build xcode project. Run "xcrun devicectl device install app --device " Run "xcrun devicectl device process launch --console --device " PLATFORM AND VERSION iOS Development environment: Xcode 16.4, macOS macOS Sequoia 15.5 Run-time configuration: iOS 18.5 main.cpp I attached is sample code to reproduce this problem. main.cpp
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Aug ’25
How to use Xcode's provided tkinter module ?
Hi there, I’m having issue with the python3 installation provided by Xcode’s toolchain. I’m currently writing a LLDB plugin, using the LLDB python API, to allow the user to visualize audio data from the current debugged program in a GUI, using tkinter and matplotlib. I'm using those because I'm developing a cross-platform plugin, as I'm initially a Linux developer who wants to make this available to my fellow Apple audio devs. My issue arise at least on two setups MacOS 12.7.6 Monterey with Xcode 14.2 MacOS 14 with Xcode 15.4 (not my machine) Because I wanna support Xcode’s toolchain, I want to use Xcode’s lldb. Xcode’s lldb uses Xcode’s provided python, which I’m having issues with when loading tkinter.The issue can be reproduced like this : > xcrun python3 -c "import tkinter;tkinter._test()" macOS 12 (1207) or later required, have instead 12 (1206) ! zsh: abort xcrun python3 -c "import tkinter;tkinter._test()" On MacOS 14 the version numbers are : macOS 14 (1407) or later required, have instead 14 (1406) ! You can see it fails to load tkinter. From what I understood so far, it looks like the tkinter/tcl/tk version distributed with Xcode is not supported by MacOS ?I checked and the imported tkinter module is definitely the one provided by Xcode’s toolchain : # Checking where tkinter is installed > fd "^tkinter$" /Applications/Xcode.app /Applications/Xcode.app/Contents/Developer/Library/Frameworks/Python3.framework/Versions/3.8/lib/python3.8/tkinter/ /Applications/Xcode.app/Contents/Developer/Library/Frameworks/Python3.framework/Versions/3.9/lib/python3.9/tkinter/ /Applications/Xcode.app/Contents/Developer/Library/Frameworks/Python3.framework/Versions/3.9/lib/python3.9/site-packages/future/moves/tkinter/ # Checking that Xcode python uses the right module - it matches > xcrun python3 -c "import tkinter;print(tkinter.sys.modules['tkinter'])" <module 'tkinter' from '/Applications/Xcode.app/Contents/Developer/Library/Frameworks/Python3.framework/Versions/3.9/lib/python3.9/tkinter/__init__.py'> I can get a working tkinter working by installing it using homebrew or macports, but I’m not able to use it with Xcode’s python installation. I tried overwriting sys.path to force Xcode’s python to import homebrew’s tkinter module, but it still loads Xcode’s tkinter .so. In the crash report I can see it indeed loads tcl/tk 8.5 and loads _tkinter.cpython-39-darwin.so from Xcode. I could disable the SIP (System Integrity Protection) to force to load another version of the library, but that wouldn’t be something I can ask the users. On the LLDB forum, they advise against using another python interpreter that the one provided by the toolchain. So is there a way to get the provided tkinter/tcl/tk installation to work ? If not I’m confused about why it’s provided in the first place. Thanks a lot for your time and please tell me if you have any questions. PS: if possible i'll post the head of the crash report in the comment of this post
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2.6k
Oct ’24
Problem with deleting SDP service (macOS, IOBluetooth)
Hello everyone. macOS, IOBluetooth framework. My goal is to create a temporary SDP service. According to the documentation, by default a temporary service is created (aka Persistent = NO), which is deleted after the application is closed. The documentation also mentions the IOBluetoothRemoveServiceWithRecordHandle function for forced removal of the service. This function is deprecated and is currently unavailable. I guesse that it has been replaced by the IOBluetoothSDPServiceRecord.removeServiceRecord method. The essence of the problem is that the server is not deleted either using removeServiceRecord or even after app closing. That is, if you create several services and try to delete them, they will remain alive. Only turning Bluetooth off and on in the OS helps. I tested all versions of macOS starting with Monteray. The same behavior. for (int i = 0; i < 10; i++) { service = [IOBluetoothSDPServiceRecord publishedServiceRecordWithDictionary:dictionary]; if (!service) { NSLog(@"Failed to create service"); } else { [service getRFCOMMChannelID:&channelID]; [service getServiceRecordHandle:&serverHandle]; NSLog(@"A new service has been created handle=%u, channelID=%hhu", serverHandle, channelID); if (service.removeServiceRecord != kIOReturnSuccess) { NSLog(@"Failed to delete service"); } //service.release; service = nil; } } Can someone confirm this behavior? And is there a solution? A minimal test example is available at the link
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Dec ’24
Unexpected behavior of dispatch_main on macOS
Hi! We are seeing a bit surprising behavior of dispatch_main on macOS where it seems to spawn a different thread instead of preserving the one it gets called from. Managed to reproduce it in a completely empty command-line tool project in Xcode int main(int argc, const char * argv[]) { @autoreleasepool { dispatch_main(); return 0; } } I put a breakpoint on the line with dispatch_main and see that I am on Thread 1 and inside main function. That makes sense. I resume execution and pause again. Looking at Thread output in Xcode, I can only see Thread 2. Thread 1 is gone and the executable keeps on running. So dispatch_main did what was expected (prevented the process from termination) but throws out the thread it was called from and creates a new one? Is that behavior expected or am I missing something? Just a brain teaser at this point. But we could not make sense out of it. :)
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Jan ’25
libsystem_c.dylib: Assertion failed: (p->val == key), function lookup_substsearch, file collate.c, line 596.
At least with macOS Sequoia 15.5 and Xcode 16.3: $ cat test.cc #include &amp;lt;locale.h&amp;gt; #include &amp;lt;string.h&amp;gt; #include &amp;lt;xlocale.h&amp;gt; int main(void) { locale_t l = newlocale(LC_ALL_MASK, "el_GR.UTF-8", 0); strxfrm_l(NULL, "ό", 0, l); return 0; } $ c99 test.c &amp;amp;&amp;amp; ./a.out Assertion failed: (p-&amp;gt;val == key), function lookup_substsearch, file collate.c, line 596. Abort trap: 6
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May ’25
Integrating App Clips in .NET MAUI iOS APP
We have an iOS App built in .NET MAUI (Multi-platform App UI). This is a web view App. We wish to integrate APP Clips into this App. But we are unable to do it, due to less available resources online on such implementation. We do not wish to share code between .NET MAUI App and App clips We understand it is not possible to add APP Clips without a parent swift/Xcode app. As an alternative solution we were thinking to Create a new APP in APP Store Connect using XCode/swift and integrate app clips to it. This parent app when downloaded by users will only redirect users to our MAIN .NET MAUI app to app store connect. We need to know if such apps will be approved by APPSTORE Connect? Please guide us on this Also please do let us know if you have any other solution to integrate App clips to a .NET MAUI App
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Jun ’25