General: TN3151 Choosing the right networking API Networking Overview document — Despite the fact that this is in the archive, this is still really useful. TLS for App Developers DevForums post Choosing a Network Debugging Tool documentation WWDC 2019 Session 712 Advances in Networking, Part 1 — This explains the concept of constrained networking, which is Apple’s preferred solution to questions like How do I check whether I’m on Wi-Fi? TN3135 Low-level networking on watchOS Adapt to changing network conditions tech talk Foundation networking: DevForums tags: Foundation, CFNetwork URL Loading System documentation — NSURLSession, or URLSession in Swift, is the recommended API for HTTP[S] on Apple platforms. Network framework: DevForums tag: Network Network framework documentation — Network framework is the recommended API for TCP, UDP, and QUIC on Apple platforms. Building a custom peer-to-peer protocol sample code (aka TicTacToe) Implementing netcat with Network Framework sample code (aka nwcat) Configuring a Wi-Fi accessory to join a network sample code Moving from Multipeer Connectivity to Network Framework DevForums post Network Extension (including Wi-Fi on iOS): See Network Extension Resources Wi-Fi Fundamentals Wi-Fi on macOS: DevForums tag: Core WLAN Core WLAN framework documentation Wi-Fi Fundamentals Secure networking: DevForums tags: Security Apple Platform Security support document Preventing Insecure Network Connections documentation — This is all about App Transport Security (ATS). Available trusted root certificates for Apple operating systems support article Requirements for trusted certificates in iOS 13 and macOS 10.15 support article About upcoming limits on trusted certificates support article Apple’s Certificate Transparency policy support article What’s new for enterprise in iOS 18 support article — This discusses new key usage requirements. Technote 2232 HTTPS Server Trust Evaluation Technote 2326 Creating Certificates for TLS Testing QA1948 HTTPS and Test Servers Miscellaneous: More network-related DevForums tags: 5G, QUIC, Bonjour On FTP DevForums post Using the Multicast Networking Additional Capability DevForums post Investigating Network Latency Problems DevForums post Local Network Privacy FAQ DevForums post Extra-ordinary Networking DevForums post Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com"

Until now I was using FileManager.contentsEqual(atPath:andPath:) to compare file contents in my App Store app, but then a user reported that this operation is way slower than just copying the files (which I made faster a while ago, as explained in Making filecopy faster by changing block size). I thought that maybe the FileManager implementation reads the two files with a small block size, so I implemented a custom comparison with the same block size I use for filecopy (as explained in the linked post), and it runs much faster. When using the code for testing repeatedly also found on that other post, this new implementation is about the same speed as FileManager for 1KB files, but runs 10-20x faster for 1MB files or bigger. Feel free to comment on my implementation below. extension FileManager { func fastContentsEqual(atPath path1: String, andPath path2: String, progress: (_ delta: Int) -> Bool) -> Bool { do { let bufferSize = 16_777_216 let sourceDescriptor = open(path1, O_RDONLY | O_NOFOLLOW, 0) if sourceDescriptor < 0 { throw NSError(domain: NSPOSIXErrorDomain, code: Int(errno)) } let sourceFile = FileHandle(fileDescriptor: sourceDescriptor) let destinationDescriptor = open(path2, O_RDONLY | O_NOFOLLOW, 0) if destinationDescriptor < 0 { throw NSError(domain: NSPOSIXErrorDomain, code: Int(errno)) } let destinationFile = FileHandle(fileDescriptor: destinationDescriptor) var equal = true while autoreleasepool(invoking: { let sourceData = sourceFile.readData(ofLength: bufferSize) let destinationData = destinationFile.readData(ofLength: bufferSize) equal = sourceData == destinationData return sourceData.count > 0 && progress(sourceData.count) && equal }) { } if close(sourceDescriptor) < 0 { throw NSError(domain: NSPOSIXErrorDomain, code: Int(errno)) } if close(destinationDescriptor) < 0 { throw NSError(domain: NSPOSIXErrorDomain, code: Int(errno)) } return equal } catch { return contentsEqual(atPath: path1, andPath: path2) // use this as a fallback for unsupported files (like symbolic links) } } }

I was trying to evaulate let myTuple = ("blue", false) let otherTuple = ("blue", true) if myTuple < otherTuple { print("yes it evaluates") } Ans I got /tmp/S9jAk7P7KW/main.swift:5:12: error: binary operator '<' cannot be applied to two '(String, Bool)' operands if myTuple < otherTuple { My question is why there is no compile time issue in first place where the declaration is let myTuple = ("blue", false) ~~~~~~ something like above

When I connect to another Mac via Finder (using SMB), creating a hard link with FileManager.linkItem(atPath:toPath:) fails (both source and destination are on the remote Mac). I read online that SMB itself supports creating hard links, so is this a macOS limitation or bug?

Download the Foundation Models Adaptor Training Toolkit Hi, after I clicked on the download button, I was redirected to this page https://developer.apple.com and did not download the toolkit.

Hey, there are plans to design a government app. When a citizen will login they will see their passport, driving license etc... What is the solution of avoiding mandatory in-app user data deletion?

Product & Version: iOS 17.5.1 (21F90) – reproducible since iOS 13 Test devices: iPhone 14 Pro, iPhone 15, iPad (10th gen) Category: UIKit → Text Input / Keyboard Summary: If the system “Save Password?” prompt (shown by iCloud Keychain after a successful login) is onscreen and the user sends the app to background (Home gesture / App Switcher), the prompt is automatically dismissed. When the app returns to foreground, the keyboard does not appear, and text input is impossible in the entire app until it is force-quit. Steps to Reproduce: Run any app from AppStore that shows "Save Password" alert. Enter any credentials and tap Login, iOS shows the system “Save Password?” alert. Without interacting with the alert, swipe up to the Home screen (or open the App Switcher). Reactivate the app. Tap the text field in the app.

After iOS 18, some new categories of crash exceptions appeared online, such as those related to the sqlite pcache1 module, those related to the photo album PHAsset, those related to various objc_release crashes, etc. These crash scenarios and stacks are all different, but they all share a common feature, that is, they all crash due to accessing NULL or NULL addresses with a certain offset. According to the analysis, the direct cause is that a certain pointer, which previously pointed to valid memory content, has now become pointing to 0 incorrectly and mysteriously. We tried various methods to eliminate issues such as multi-threading problems. To determine the cause of the problem, we have a simulated malloc guard detection in production. The principle is very simple: Create some private NSString objects with random lengths, but ensure that they exceed the size of one memory physical page. Set the first page of memory for these objects to read-only (aligning the object address with the memory page). After a random period of time (3s - 10s), reset the memory of these objects to read/write and immediately release these objects. Then repeat the operation starting from step 1. In this way, if an abnormal write operation is performed on the memory of these objects, it will trigger a read-only exception crash and report the exception stack. Surprisingly, after the malloc guard detection was implemented, some crashes occurred online. However, the crashes were not caused by any abnormal rewriting of read-only memory. Instead, they occurred when the NSString objects were released as mentioned earlier, and the pointers pointed to contents of 0. Therefore, we have added object memory content printing after object generation, before and after setting to read-only, and before and after reverting to read-write. The result was once again unexpected. The log showed that the isa pointer of the object became 0 after setting to read-only and before re-setting to read-write. So why did it become 0 during read-only mode, but no crash occurred due to the read-only status? We have revised the plan again. We have added a test group, in which after the object is created, we will mlock the memory of the object, and then munlock it again before the object is released. As a result, the test analysis showed that the test group did not experience a crash, while the crashes occurred entirely in the control group. In this way, we can prove that the problem occurs at the system level and is related to the virtual memory function of the operating system. It is possible that inactive memory pages are compressed and then cleared to zero, and subsequent decompression fails. This results in the accidental zeroing out of the memory data. As mentioned at the beginning, althougth this issue is a very rare occurrence, but it exists in various scenarios. definitely It appeared after iOS 18. We hope that the authorities will pay attention to this issue and fix it in future versions.

We are testing our existing live build, which was prepared with Xcode 16.2, on iOS 26 beta for experience assurance and found that the [[UIDevice currentDevice] systemVersion] API is returning iOS 19 instead of the expected version iOS 26. Has anyone else observed this issue?

I have an iOS app that includes a local Swift package. This Swift package contains some .plist files added as resources. The package also depends on an XCFramework. I want to read these .plist files from within the XCFramework. What I’d like to know is: Is this a common or recommended approach—having resources in a Swift package and accessing them from an XCFramework? Previously, I had the .plist files added directly to the main app target, and accessing them from the XCFramework felt straightforward. With the new setup, I’m trying to determine whether this method (placing resources in a Swift package and accessing them from an XCFramework) is considered good practice. For context: I am currently able to read the .plist files from the XCFramework by passing Bundle.module through one of the APIs exposed by the XCFramework.

hi,guys.There's a issue about my app about NSuserdefault. Everything is arlright if i stay in the app, once i close my app, and restart it.Datas from nsuserdefault is gone(nil). i tried to add and delete synchronize method , but its not working. But this situation only happens in ios 18.(at least ios12 and ios16 is alright).

I’m running iOS 26 Developer Beta 2 on my iPhone 13 Pro and it’s not letting me call anyone on it you should fi that with the next beta of iOS 26 and every one of the iOS 26 beta updates after that even when you release the up iOS 26 later this fall

Hello everyone, I think I've discovered a bug in JSONDecoder and I'd like to get a quick sanity-check on this, as well as hopefully some ideas to work around the issue. When attempting to decode a Decodable struct from JSON using JSONDecoder, the decoder throws an error when it encounters a dictionary that is keyed by an enum and somehow seems to think that the enum is an Array<Any>. Here's a minimal reproducible example: let jsonString = """ { "variations": { "plural": "tests", "singular": "test" } } """ struct Json: Codable { let variations: [VariationKind: String] } enum VariationKind: String, Codable, Hashable { case plural = "plural" case singular = "singular" } and then the actual decoding: let json = try JSONDecoder().decode( Json.self, from: jsonString.data(using: .utf8)! ) print(json) The expected result would of course be the following: Json( variations: [ VariationKind.plural: "tests", VariationKind.singular: "test" ] ) But the actual result is an error: Swift.DecodingError.typeMismatch( Swift.Array<Any>, Swift.DecodingError.Context( codingPath: [ CodingKeys(stringValue: "variations", intValue: nil) ], debugDescription: "Expected to decode Array<Any> but found a dictionary instead.", underlyingError: nil ) ) So basically, the JSONDecoder tries to decode Swift.Array<Any> but encounters a dictionary (duh), and I have no idea why this is happening. There are literally no arrays anywhere, neither in the actual JSON string, nor in any of the Codable structs. Curiously, if I change the dictionary from [VariationKind: String] to [String: String], everything works perfectly. So something about the enum seems to cause confusion in JSONDecoder. I've tried to fix this by implementing Decodable myself for VariationKind and using a singleValueContainer, but that causes exactly the same error. Am I crazy, or is that a bug?

Hello, I have encountered an issue with an iPhone 15PM with iOS 18.5. The NSHTTPCookieStorage failed to clear cookies, after clearing them, I was still able to retrieve them. However, on the same system NSHTTPCookie *cookie; NSHTTPCookieStorage *storage = [NSHTTPCookieStorage sharedHTTPCookieStorage]; for (cookie in [storage cookies]) { [storage deleteCookie:cookie]; } NSArray *cookies = [[NSHTTPCookieStorage sharedHTTPCookieStorage] cookiesForURL:[[self url] absoluteURL]]; // still able to get cookies,why???

Either processInfo.hostName should return the same info as UIDevice.name ("iPhone") or it should require the same entitlement that UIDevice.name does to return the actual result. If processInfo.hostName is intended to return the local Bonjour name, why does it need 'local network' permission? Why isn't the 'local network' permission documented for processInfo.hostName as this is hard to track down? Tested on iOS 18.5

Description: I'm noticing that when using the completion handler variant of URLSession.dataTask(with:), the delegate method urlSession(_:dataTask:didReceive:) is not called—even though a delegate is set when creating the session. Here's a minimal reproducible example: ✅ Case where delegate method is called: class CustomSessionDelegate: NSObject, URLSessionDataDelegate { func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) { print("✅ Delegate method called: Data received") } } let delegate = CustomSessionDelegate() let session = URLSession(configuration: .default, delegate: delegate, delegateQueue: nil) let request = URLRequest(url: URL(string: "https://httpbin.org/get")!) let task = session.dataTask(with: request) // ✅ No completion handler task.resume() In this case, the delegate method didReceive is called as expected. ❌ Case where delegate method is NOT called: class CustomSessionDelegate: NSObject, URLSessionDataDelegate { func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) { print("❌ Delegate method NOT called") } } let delegate = CustomSessionDelegate() let session = URLSession(configuration: .default, delegate: delegate, delegateQueue: nil) let request = URLRequest(url: URL(string: "https://httpbin.org/get")!) let task = session.dataTask(with: request) { data, response, error in print("Completion handler called") } task.resume() Here, the completion handler is executed, but the delegate method didReceive is never called. Notes: I’ve verified this behavior on iOS 16, 17, and 18. Other delegate methods such as urlSession(_:task:didFinishCollecting:) do get called with the completion handler API. This happens regardless of whether swizzling or instrumentation is involved — the issue is reproducible even with direct method implementations. Questions: Is this the expected behavior (i.e., delegate methods like didReceive are skipped when a completion handler is used)? If yes, is there any official documentation that explains this? Is there a recommended way to ensure delegate methods are invoked, even when using completion handler APIs? Thanks in advance!

Does the new TextEditor in iOS 26, which supports rich text / AttributedString, also support the ability to add text attachments or tokens? For example, in Xcode, we can type <#foo#> to create an inline text placeholder/token which can be interacted with in a different way than standard text.

This is the issues I faced: NSBundle file:///System/Library/PrivateFrameworks/MetalTools.framework/ principal class is nil because all fallbacks have failed How can I fix it because I'm not sure if I dowloaded the application correctly.

I am trying out the new AttributedString binding with SwiftUI’s TextEditor in iOS26. I need to save this to a Core Data database. Core Data has no AttributedString type, so I set the type of the field to “Transformable”, give it a custom class of NSAttributedString, and set the transformer to NSSecureUnarchiveFromData When I try to save, I first convert the Swift AttributedString to NSAttributedString, and then save the context. Unfortunately I get this error when saving the context, and the save isn't persisted: CoreData: error: SQLCore dispatchRequest: exception handling request: <NSSQLSaveChangesRequestContext: 0x600003721140> , <shared NSSecureUnarchiveFromData transformer> threw while encoding a value. with userInfo of (null) Here's the code that tries to save the attributed string: struct AttributedDetailView: View { @ObservedObject var item: Item @State private var notesText = AttributedString() var body: some View { VStack { TextEditor(text: $notesText) .padding() .onChange(of: notesText) { item.attributedString = NSAttributedString(notesText) } } .onAppear { if let nsattributed = item.attributedString { notesText = AttributedString(nsattributed) } else { notesText = "" } } .task { item.attributedString = NSAttributedString(notesText) do { try item.managedObjectContext?.save() } catch { print("core data save error = \(error)") } } } } This is the attribute setup in the Core Data model editor: Is there a workaround for this? I filed FB17943846 if someone can take a look. Thanks.

The value of ProcessInfo.processInfo.operatingSystemVersion on iOS 26 is returning 19.0.0 would of expected 26.0.0

We just dropped support for iOS 16 in our app and migrated to the new properties on Locale to extract the language code, region, and script. However, after doing this we are seeing an issue where the script property is returning a value when the language has no script. Here is the initializer that we are using to populate the values. The identifier is coming from the preferredLanguages property that is found on Locale. init?(identifier: String) { let locale = Locale(identifier: identifier) guard let languageCode = locale.language.languageCode?.identifier else { return nil } language = languageCode region = locale.region?.identifier script = locale.language.script?.identifier } Whenever I inspect locale.language I see all of the correct values. However, when I inspect locale.language.script directly it is always returning Latn as the value. If I inspect the deprecated locale.scriptCode property it will return nil as expected. Here is an example from the debugger for en-AU. I also see the same for other languages such as en-AE, pt-BR. Since the language components show the script as nil, then I would expect locale.language.script?.identifier to also return nil.