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"_swift_coroFrameAlloc", 报错
Undefined symbols for architecture arm64: "_swift_coroFrameAlloc", referenced from: NvMobileCore.Constraint.isActive.modify : Swift.Bool in NvMobileCore[5] NvMobileCore.Constraint.isActive.modify : Swift.Bool in NvMobileCore[5] NvMobileCore.NvMobileCoreManager.delegate.modify : NvMobileCore.NvPublicInterface? in NvMobileCore[53] NvMobileCore.NvMobileCoreManager.delegate.modify : NvMobileCore.NvPublicInterface? in NvMobileCore[53] NvMobileCore.NvMobileCoreManager.language.modify : Swift.String in NvMobileCore[53] NvMobileCore.NvMobileCoreManager.language.modify : Swift.String in NvMobileCore[53] ld: symbol(s) not found for architecture arm64 clang: error: linker command failed with exit code 1 (use -v to see invocation)
2
0
844
Oct ’25
Adding days to a date using the result of a division operation
var testTwo: Double = 0 testDouble = 80 testTwo = 200 var testThree: Int = 0 testThree = Int(testTwo/testDouble) var testDate: Date = .now var dateComponent = DateComponents() dateComponent.day = testThree var newDate: Date = Calendar.current.date(byAdding: dateComponentwith a thread error , to: testDate)! This code works in a playground. However, when I try to use it in Xcode for my app it fails with the following error: Thread 1: Fatal error: Double value cannot be converted to Int because it is either infinite or NaN I printed the value being converted to Int and it was not NAN or infinite.
2
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917
Nov ’25
Async function doesn’t see external changes to an inout Bool in Release build
Title Why doesn’t this async function see external changes to an inout Bool in Release builds (but works in Debug)? Body I have a small helper function that waits for a Bool flag to become true with a timeout: public func test(binding value: inout Bool, timeout maximum: Int) async throws { var count = 0 while value == false { count += 1 try await Task.sleep(nanoseconds: 0_100_000_000) if value == true { return } if count > (maximum * 10) { return } } } I call like this: var isVPNConnected = false adapter.start(tunnelConfiguration: tunnelConfiguration) { [weak self] adapterError in guard let self = self else { return } if let adapterError = adapterError { } else { isVPNConnected = true } completionHandler(adapterError) } try await waitUntilTrue(binding: &isVPNConnected, timeout: 10) What I expect: test should keep looping until flag becomes true (or the timeout is hit). When the second task sets flag = true, the first task should see that change and return. What actually happens: In Debug builds this behaves as expected: when the second task sets flag = true, the loop inside test eventually exits. In Release builds the function often never sees the change and gets stuck until the timeout (or forever, depending on the code). It looks like the while value == false condition is using some cached value and never observes the external write. So my questions are: Is the compiler allowed to assume that value (the inout Bool) does not change inside the loop, even though there are await suspension points and another task is mutating the same variable? Is this behavior officially “undefined” because I’m sharing a plain Bool across tasks without any synchronization (actors / locks / atomics), so the debug build just happens to work? What is the correct / idiomatic way in Swift concurrency to implement this kind of “wait until flag becomes true with timeout” pattern? Should I avoid inout here completely and use some other primitive (e.g. AsyncStream, CheckedContinuation, Actor, ManagedAtomic, etc.)? Is there any way to force the compiler to re-read the Bool from memory each iteration, or is that the wrong way to think about it? Environment (if it matters): Swift: [fill in your Swift version] Xcode: [fill in your Xcode version] Target: iOS / macOS [fill in as needed] Optimization: default Debug vs. Release settings I’d like to understand why Debug vs Release behaves differently here, and what the recommended design is for this kind of async waiting logic in Swift.
2
0
1.3k
Nov ’25
NotificationCenter Crash On iOS 18+ Swift6.2
After switching our iOS app project from Swift 5 to Swift 6 and publishing an update, we started seeing a large number of crashes in Firebase Crashlytics. The crashes are triggered by NotificationCenter methods (post, addObserver, removeObserver) and show the following error: BUG IN CLIENT OF LIBDISPATCH: Assertion failed: Block was expected to execute on queue [com.apple.main-thread (0x1f9dc1580)] All scopes to related calls are already explicitly marked with @MainActor. This issue never occurred with Swift 5, but appeared immediately after moving to Swift 6. Has anyone else encountered this problem? Is there a known solution or workaround? Thanks in advance!
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1
1.6k
Nov ’25
NSWindowController subclass in Swift
In trying to convert some Objective-C to Swift, I have a subclass of NSWindowController and want to write a convenience initializer. The documentation says You can also implement an NSWindowController subclass to avoid requiring client code to get the corresponding nib’s filename and pass it to init(windowNibName:) or init(windowNibName:owner:) when instantiating the window controller. The best way to do this is to override windowNibName to return the nib’s filename and instantiate the window controller by passing nil to init(window:). My attempt to do that looks like this: class EdgeTab: NSWindowController { override var windowNibName: NSNib.Name? { "EdgeTab" } required init?(coder: NSCoder) { super.init(coder: coder) } convenience init() { self.init( window: nil ) } } But I'm getting an error message saying "Incorrect argument label in call (have 'window:', expected 'coder:')". Why the heck is the compiler trying to use init(coder:) instead of init(window:)?
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728
Dec ’25
Parameter Errors - procedural vs. optional
So I’m writing a program, as a developer would - ‘with Xcode.’ Code produced an error. The key values were swapped. The parameters suggested were ‘optional parameters variables.’ “var name: TYPE? = (default)” var name0: TYPE ============================= name0 = “super cool” ‘Name is not yet declared at this point provided with x - incorrect argument replace ExampleStruct(name:”supercool”) should be x - incorrect argument replace ExampleStruct(name0:”supercool”) ============================= In swift, there is a procedural prioritization within the constructor calling process. Application calls constructor. Constructor provides constructor signature. Signature requires parameters & throws an error if the params are not in appropriate order. - “got it compiler; thank you, very much” Typically, when this occurs, defaults will be suggested. Often the variable type. Ie String, Bool. such as: StructName(param1:Int64, param2:Bool) (Recently, I have seen a decline in @Apple’s performance in many vectors.) As stated before, the key value pairs were out of sequence. The optionals were suggested instead of the required parameters. This leads me to believe that there is an order of operations in the calling procedure that is being mismanaged. I.e. regular expression, matching with optional. This confuses these with [forced, required] parameters, and the mismanagement of ‘key: value’ pairs. this is a superficial prognosis and would like to know if anyone has any insight as to why this may occur. Could it be a configuration setting? Is it possibly the network I connected to bumped into something. Etc.. I appreciate any and all feedback. Please take into consideration the Apple developer forum, guidelines before posting comments. #dev_div
2
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651
Jan ’26
iOS and Android
I currently have a iOS app live on the App Store but I also want to release it on Android, the whole code is in Swift so would that be possible or would I have to rewrite my whole apps code in a different coding language.
2
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2.7k
Jan ’26
init?(coder: NSCoder) or init?(coder: (NSCoder?))
In this code, I use in some places required init?(coder: (NSCoder?)) { // Init some properties super.init(coder: coder!) } And in other places required init?(coder: NSCoder) { super.init(coder: coder) // Init some properties } Both seem to work. Is there a preferred one ? In which cases ? Or should I always use the second one ? And can super be called at anytime ?
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598
3w
Not understanding synchronous/asynchronous code
Hello, For the below code please can you tell me why the test code print("line 64") is being printed after the test code print("line 84") ? (i.e. how do I stop that happening?) I would like the program to wait until the results array has been parsed before continuing the code (otherwise it does not have content to present). I'm a bit confused why this is happening because I haven't written "async" anywhere. import UIKit struct NewsFeed: Codable { var id: String var name: String var country: String var type: String var situation: String var timestamp: String } class QuoteTableViewController: UITableViewController { var newsFeed: [[String: String]] = [] override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) { // let selectedQuote = quotes[indexPath.row] // performSegue(withIdentifier: "moveToQuoteDetail", sender: selectedQuote) } override func viewDidLoad() { super.viewDidLoad() // tableView.dataSource = self } // Uncomment the following line to preserve selection between presentations // self.clearsSelectionOnViewWillAppear = false // Uncomment the following line to display an Edit button in the navigation bar for this view controller. // self.navigationItem.rightBarButtonItem = self.editButtonItem // MARK: - Table view data source override func numberOfSections(in tableView: UITableView) -> Int { // #warning Incomplete implementation, return the number of sections return 1 } override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { // (viewDidLoad loads after tableView) // try getting array results here let urlString = "https://www.notafunnyname.com/jsonmockup.php" let url = URL(string: urlString) let session = URLSession.shared let dataTask = session.dataTask(with: url!) { (data, response, error) in var dataString = String(data: data!, encoding: String.Encoding.utf8) if error == nil && data != nil { // Parse JSON let decoder = JSONDecoder() do { var newsFeed = try decoder.decode([NewsFeed].self, from: data!) print("line 64") // print(newsFeed) // print("line 125") // print(newsFeed.count) print(error) } catch{ print("Line 72, Error in JSON parsing") print(error) } } } // Make the API Call dataTask.resume() // #warning Incomplete implementation, return the number of rows print("line 84") print(newsFeed.count) return 10 } override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell { // let cell = tableView.dequeueReusableCell(withIdentifier: "reuseIdentifier", for: indexPath) let cell = UITableViewCell () cell.textLabel?.text = "test" return cell } /* // Override to support conditional editing of the table view. override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool { // Return false if you do not want the specified item to be editable. return true } */ /* // Override to support editing the table view. override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) { if editingStyle == .delete { // Delete the row from the data source tableView.deleteRows(at: [indexPath], with: .fade) } else if editingStyle == .insert { // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view } } */ /* // Override to support rearranging the table view. override func tableView(_ tableView: UITableView, moveRowAt fromIndexPath: IndexPath, to: IndexPath) { } */ /* // Override to support conditional rearranging of the table view. override func tableView(_ tableView: UITableView, canMoveRowAt indexPath: IndexPath) -> Bool { // Return false if you do not want the item to be re-orderable. return true } */ // MARK: - Navigation // In a storyboard-based application, you will often want to do a little preparation before navigation override func prepare(for segue: UIStoryboardSegue, sender: Any?) { // Get the new view controller using segue.destination. // Pass the selected object to the new view controller. // getPrice() print("test_segue") if let quoteViewController = segue.destination as? QuoteDetailViewController{ if let selectedQuote = sender as? String { quoteViewController.title = selectedQuote } } } } Many thanks
1
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148
Mar ’25
Why does Array.contains cause a compile-time error when comparing an optional value with a non-optional value in Swift?
I’m working with Swift and ran into an issue when using the contains(_:) method on an array. The following code works fine: let result = ["hello", "world"].contains(Optional("hello")) // ✅ Works fine But when I try to use the same contains method with the array declared in a separate variable, I get a compile-time error: let stringArray = ["hello", "world"] let result = stringArray.contains(Optional("hello")) // ❌ Compile-time error Both examples seem conceptually similar, but the second one causes a compile-time error, while the first one works fine. I understand that when comparing an optional value (Optional("hello")) with a non-optional value ("hello"), Swift automatically promotes the non-optional value to an optional (i.e., "hello" becomes Optional("hello")). 🔗 reference What I don’t understand is why the first code works but the second one doesn’t, even though both cases involve comparing an optional value with a non-optional value. I know that there are different ways to resolve this, like using nil coalescing or optional binding, but what I’m really looking for is a detailed explanation of why this issue occurs at the compile-time level. Can anyone explain the underlying reason for this behavior?
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147
Mar ’25
Help!
I am a Chinese student beginner ,do you have any advice for me to learn swift?I don't know how to start it.Please!🙏
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190
Apr ’25
Crash when Mutating Array of Tuples with String Property from Multiple Threads
Hi Apple Developer Community, I'm facing a crash when updating an array of tuples from both a background thread and the main thread simultaneously. Here's a simplified version of the code in a macOS app using AppKit: class ViewController: NSViewController { var mainthreadButton = NSButton(title: "test", target: self, action: nil) var numbers = Array(repeating: (dim: Int, key: String)(0, "default"), count: 1000) override func viewDidLoad() { super.viewDidLoad() view.addSubview(mainthreadButton) mainthreadButton.translatesAutoresizingMaskIntoConstraints = false mainthreadButton.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true mainthreadButton.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true mainthreadButton.widthAnchor.constraint(equalToConstant: 100).isActive = true mainthreadButton.heightAnchor.constraint(equalToConstant: 100).isActive = true mainthreadButton.target = self mainthreadButton.action = #selector(arraytest(_:)) } @objc func arraytest(_ sender: NSButton) { print("array update started") // Background update DispatchQueue.global().async { for i in 0..<1000 { self.numbers[i].dim = i } } // Main thread update var sum = 0 for i in 0..<1000 { numbers[i].dim = i + 1 sum += numbers[i].dim print("test \(sum)") } mainthreadButton.title = "test = \(sum)" } } This results in a crash with the following message: malloc: double free for ptr 0x136040c00 malloc: *** set a breakpoint in malloc_error_break to debug What's interesting: This crash only happens when the tuple contains a String ((dim: Int, key: String)) If I change the tuple type to use two Int values ((dim: Int, key: Int)), the crash does not occur My Questions: Why does mutating an array of tuples containing a String crash when accessed from multiple threads? Why is the crash avoided when the tuple contains only primitive types like Int? Is there an underlying memory management issue with value types containing reference types like String? Any explanation about this behavior and best practices for thread-safe mutation of such arrays would be much appreciated. Thanks in advance!
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296
Apr ’25
Actors with Combine publishers as properties.
Is it ok for an Actor type to have a Publisher as a property to let others observe changes over time? Or use the @Published property wrapper to achieve this? actor MyActor { var publisher = PassthroughSubject<Int, Never>() var data: Int { didSet { publisher.send(data) } } ... } // Usage var tasks = Set<AnyCancellable>() let actor = MyActor() Task { let publisher = await actor.publisher publisher.sink { print($0) }.store(in: &tasks) } This seems like this should be acceptable. I would expect a Publisher to be thread safe, and as long as the Output is a value type things should be fine. I have been getting random EXC_BAD_ACCESS errors when using this approach. But turning on the address sanitizer causes these crashes to go away. I know that isn't very specific but I wanted to start by seeing if this type of pattern is ok to do.
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6
2.8k
Apr ’25
Open any Swift view from C++
I've narrowed down my question after many rabbit holes - how can C++ code open any view in Swift. I can call functions in swift from C++ (works great), but not async or main actor (or actor at all) functions. And if I'm not mistaken all views are actors if not main actors? When calling from C+ I think its necessary that the first view be the main actor? I've implemented the code from the WWDC23 C++ interop video (Zoe's image picker) where I made a view in a struct, and just want to call it and let the view do the work. The compiler immediately gives me 'cannot expose main actors to C++'. If I'm not mistaken, doesn't this block the opening of any kind of swift view from C++? Hopefully I'm missing something obvious, which is likely :) In Zoe's code was his entry point into the program still Swift and not actually C++ app? Thanks! Thanks!
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160
May ’25
'init(coordinateRegion:interactionModes:showsUserLocation:userTrackingMode:annotationItems:annotationContent:)' was deprecated in iOS 17.0: Use Map initializers that t
I am currently encountering two deprecated errors in my code. Could someone please identify the issues with the code? Errors: 'init(coordinateRegion:interactionModes:showsUserLocation:userTrackingMode:annotationItems:annotationContent:)' was deprecated in iOS 17.0: Use Map initializers that take a MapContentBuilder instead. 'MapAnnotation' was deprecated in iOS 17.0: Use Annotation along with Map initializers that take a MapContentBuilder instead. Code: // MARK: - Stores Map (Dynamic) struct StoresMapView: View { @State private var storeLocations: [StoreLocation] = [] @State private var region = MKCoordinateRegion( center: CLLocationCoordinate2D(latitude: -31.95, longitude: 115.86), span: MKCoordinateSpan(latitudeDelta: 0.5, longitudeDelta: 0.5) ) var body: some View { Map(coordinateRegion: $region, interactionModes: .all, annotationItems: storeLocations) { store in MapAnnotation(coordinate: CLLocationCoordinate2D(latitude: store.latitude, longitude: store.longitude)) { VStack(spacing: 4) { Image(systemName: "leaf.circle.fill") .font(.title) .foregroundColor(.green) Text(store.name) .font(.caption) .fixedSize() } } } .onAppear(perform: loadStoreData) .navigationTitle("Store Locator") } private func loadStoreData() { guard let url = URL(string: "https://example.com/cop092/StoreLocations.json") else { return } URLSession.shared.dataTask(with: url) { data, _, _ in if let data = data, let decoded = try? JSONDecoder().decode([StoreLocation].self, from: data) { DispatchQueue.main.async { self.storeLocations = decoded if let first = decoded.first { self.region.center = CLLocationCoordinate2D(latitude: first.latitude, longitude: first.longitude) } } } }.resume() } }
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0
177
May ’25
Swift Concurrency: Calling @MainActor Function from Protocol Implementation in Swift 6
I have a Settings class that conform to the TestProtocol. From the function of the protocol I need to call the setString function and this function needs to be on the MainActor. Is there a way of make this work in Swift6, without making the protocol functions running on @MainActor The calls are as follows: class Settings: TestProtocol{ var value:String = "" @MainActor func setString( _ string:String ){ value = string } func passString(string: String) { Task{ await setString(string) } } } protocol TestProtocol{ func passString( string:String ) }
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204
May ’25
Issue with Swift 6 migration issues
We are migrating to swift 6 from swift 5 using Xcode 16.2. we are getting below errors in almost each of our source code files : Call to main actor-isolated initializer 'init(storyboard:bundle:)' in a synchronous non isolated context Main actor-isolated property 'delegate' can not be mutated from a nonisolated context Call to main actor-isolated instance method 'register(cell:)' in a synchronous nonisolated context Call to main actor-isolated instance method 'setup()' in a synchronous nonisolated context Few questions related to these compile errors. Some of our functions arguments have default value set but swift 6 does not allow to set any default values. This requires a lot of code changes throughout the project. This would be lot of source code re-write. Using annotations like @uncheck sendable , @Sendable on the class (Main actor) name, lot of functions within those classes , having inside some code which coming from other classes which also showing main thread issue even we using @uncheck sendable. There are so many compile errors, we are still seeing other than what we have listed here. Fixing these compile errors throughout our project, would be like a re-write of our whole application, which would take lot of time. In order for us to migrate efficiently, we have few questions where we need your help with. Below are the questions. Are there any ways we can bypass these errors using any keywords or any other way possible? Can Swift 5 and Swift 6 co-exist? so, we can slowly migrate over a period of time.
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192
Jun ’25
"_swift_coroFrameAlloc", 报错
Undefined symbols for architecture arm64: "_swift_coroFrameAlloc", referenced from: NvMobileCore.Constraint.isActive.modify : Swift.Bool in NvMobileCore[5] NvMobileCore.Constraint.isActive.modify : Swift.Bool in NvMobileCore[5] NvMobileCore.NvMobileCoreManager.delegate.modify : NvMobileCore.NvPublicInterface? in NvMobileCore[53] NvMobileCore.NvMobileCoreManager.delegate.modify : NvMobileCore.NvPublicInterface? in NvMobileCore[53] NvMobileCore.NvMobileCoreManager.language.modify : Swift.String in NvMobileCore[53] NvMobileCore.NvMobileCoreManager.language.modify : Swift.String in NvMobileCore[53] ld: symbol(s) not found for architecture arm64 clang: error: linker command failed with exit code 1 (use -v to see invocation)
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2
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0
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844
Activity
Oct ’25
How to retrieve the % of memory pressure using native libraries
Is there any way to retrieve the memory pressure percentage using native libraries? When I run the memory-pressure command, I can see the percentage of free memory, but I’d like to retrieve the same information using a native library.
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2
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0
Views
645
Activity
Oct ’25
Adding days to a date using the result of a division operation
var testTwo: Double = 0 testDouble = 80 testTwo = 200 var testThree: Int = 0 testThree = Int(testTwo/testDouble) var testDate: Date = .now var dateComponent = DateComponents() dateComponent.day = testThree var newDate: Date = Calendar.current.date(byAdding: dateComponentwith a thread error , to: testDate)! This code works in a playground. However, when I try to use it in Xcode for my app it fails with the following error: Thread 1: Fatal error: Double value cannot be converted to Int because it is either infinite or NaN I printed the value being converted to Int and it was not NAN or infinite.
Replies
2
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0
Views
917
Activity
Nov ’25
Async function doesn’t see external changes to an inout Bool in Release build
Title Why doesn’t this async function see external changes to an inout Bool in Release builds (but works in Debug)? Body I have a small helper function that waits for a Bool flag to become true with a timeout: public func test(binding value: inout Bool, timeout maximum: Int) async throws { var count = 0 while value == false { count += 1 try await Task.sleep(nanoseconds: 0_100_000_000) if value == true { return } if count > (maximum * 10) { return } } } I call like this: var isVPNConnected = false adapter.start(tunnelConfiguration: tunnelConfiguration) { [weak self] adapterError in guard let self = self else { return } if let adapterError = adapterError { } else { isVPNConnected = true } completionHandler(adapterError) } try await waitUntilTrue(binding: &isVPNConnected, timeout: 10) What I expect: test should keep looping until flag becomes true (or the timeout is hit). When the second task sets flag = true, the first task should see that change and return. What actually happens: In Debug builds this behaves as expected: when the second task sets flag = true, the loop inside test eventually exits. In Release builds the function often never sees the change and gets stuck until the timeout (or forever, depending on the code). It looks like the while value == false condition is using some cached value and never observes the external write. So my questions are: Is the compiler allowed to assume that value (the inout Bool) does not change inside the loop, even though there are await suspension points and another task is mutating the same variable? Is this behavior officially “undefined” because I’m sharing a plain Bool across tasks without any synchronization (actors / locks / atomics), so the debug build just happens to work? What is the correct / idiomatic way in Swift concurrency to implement this kind of “wait until flag becomes true with timeout” pattern? Should I avoid inout here completely and use some other primitive (e.g. AsyncStream, CheckedContinuation, Actor, ManagedAtomic, etc.)? Is there any way to force the compiler to re-read the Bool from memory each iteration, or is that the wrong way to think about it? Environment (if it matters): Swift: [fill in your Swift version] Xcode: [fill in your Xcode version] Target: iOS / macOS [fill in as needed] Optimization: default Debug vs. Release settings I’d like to understand why Debug vs Release behaves differently here, and what the recommended design is for this kind of async waiting logic in Swift.
Replies
2
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0
Views
1.3k
Activity
Nov ’25
NotificationCenter Crash On iOS 18+ Swift6.2
After switching our iOS app project from Swift 5 to Swift 6 and publishing an update, we started seeing a large number of crashes in Firebase Crashlytics. The crashes are triggered by NotificationCenter methods (post, addObserver, removeObserver) and show the following error: BUG IN CLIENT OF LIBDISPATCH: Assertion failed: Block was expected to execute on queue [com.apple.main-thread (0x1f9dc1580)] All scopes to related calls are already explicitly marked with @MainActor. This issue never occurred with Swift 5, but appeared immediately after moving to Swift 6. Has anyone else encountered this problem? Is there a known solution or workaround? Thanks in advance!
Replies
2
Boosts
1
Views
1.6k
Activity
Nov ’25
NSWindowController subclass in Swift
In trying to convert some Objective-C to Swift, I have a subclass of NSWindowController and want to write a convenience initializer. The documentation says You can also implement an NSWindowController subclass to avoid requiring client code to get the corresponding nib’s filename and pass it to init(windowNibName:) or init(windowNibName:owner:) when instantiating the window controller. The best way to do this is to override windowNibName to return the nib’s filename and instantiate the window controller by passing nil to init(window:). My attempt to do that looks like this: class EdgeTab: NSWindowController { override var windowNibName: NSNib.Name? { "EdgeTab" } required init?(coder: NSCoder) { super.init(coder: coder) } convenience init() { self.init( window: nil ) } } But I'm getting an error message saying "Incorrect argument label in call (have 'window:', expected 'coder:')". Why the heck is the compiler trying to use init(coder:) instead of init(window:)?
Replies
2
Boosts
0
Views
728
Activity
Dec ’25
Parameter Errors - procedural vs. optional
So I’m writing a program, as a developer would - ‘with Xcode.’ Code produced an error. The key values were swapped. The parameters suggested were ‘optional parameters variables.’ “var name: TYPE? = (default)” var name0: TYPE ============================= name0 = “super cool” ‘Name is not yet declared at this point provided with x - incorrect argument replace ExampleStruct(name:”supercool”) should be x - incorrect argument replace ExampleStruct(name0:”supercool”) ============================= In swift, there is a procedural prioritization within the constructor calling process. Application calls constructor. Constructor provides constructor signature. Signature requires parameters & throws an error if the params are not in appropriate order. - “got it compiler; thank you, very much” Typically, when this occurs, defaults will be suggested. Often the variable type. Ie String, Bool. such as: StructName(param1:Int64, param2:Bool) (Recently, I have seen a decline in @Apple’s performance in many vectors.) As stated before, the key value pairs were out of sequence. The optionals were suggested instead of the required parameters. This leads me to believe that there is an order of operations in the calling procedure that is being mismanaged. I.e. regular expression, matching with optional. This confuses these with [forced, required] parameters, and the mismanagement of ‘key: value’ pairs. this is a superficial prognosis and would like to know if anyone has any insight as to why this may occur. Could it be a configuration setting? Is it possibly the network I connected to bumped into something. Etc.. I appreciate any and all feedback. Please take into consideration the Apple developer forum, guidelines before posting comments. #dev_div
Replies
2
Boosts
0
Views
651
Activity
Jan ’26
iOS and Android
I currently have a iOS app live on the App Store but I also want to release it on Android, the whole code is in Swift so would that be possible or would I have to rewrite my whole apps code in a different coding language.
Replies
2
Boosts
0
Views
2.7k
Activity
Jan ’26
init?(coder: NSCoder) or init?(coder: (NSCoder?))
In this code, I use in some places required init?(coder: (NSCoder?)) { // Init some properties super.init(coder: coder!) } And in other places required init?(coder: NSCoder) { super.init(coder: coder) // Init some properties } Both seem to work. Is there a preferred one ? In which cases ? Or should I always use the second one ? And can super be called at anytime ?
Replies
2
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0
Views
598
Activity
3w
Not understanding synchronous/asynchronous code
Hello, For the below code please can you tell me why the test code print("line 64") is being printed after the test code print("line 84") ? (i.e. how do I stop that happening?) I would like the program to wait until the results array has been parsed before continuing the code (otherwise it does not have content to present). I'm a bit confused why this is happening because I haven't written "async" anywhere. import UIKit struct NewsFeed: Codable { var id: String var name: String var country: String var type: String var situation: String var timestamp: String } class QuoteTableViewController: UITableViewController { var newsFeed: [[String: String]] = [] override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) { // let selectedQuote = quotes[indexPath.row] // performSegue(withIdentifier: "moveToQuoteDetail", sender: selectedQuote) } override func viewDidLoad() { super.viewDidLoad() // tableView.dataSource = self } // Uncomment the following line to preserve selection between presentations // self.clearsSelectionOnViewWillAppear = false // Uncomment the following line to display an Edit button in the navigation bar for this view controller. // self.navigationItem.rightBarButtonItem = self.editButtonItem // MARK: - Table view data source override func numberOfSections(in tableView: UITableView) -> Int { // #warning Incomplete implementation, return the number of sections return 1 } override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { // (viewDidLoad loads after tableView) // try getting array results here let urlString = "https://www.notafunnyname.com/jsonmockup.php" let url = URL(string: urlString) let session = URLSession.shared let dataTask = session.dataTask(with: url!) { (data, response, error) in var dataString = String(data: data!, encoding: String.Encoding.utf8) if error == nil && data != nil { // Parse JSON let decoder = JSONDecoder() do { var newsFeed = try decoder.decode([NewsFeed].self, from: data!) print("line 64") // print(newsFeed) // print("line 125") // print(newsFeed.count) print(error) } catch{ print("Line 72, Error in JSON parsing") print(error) } } } // Make the API Call dataTask.resume() // #warning Incomplete implementation, return the number of rows print("line 84") print(newsFeed.count) return 10 } override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell { // let cell = tableView.dequeueReusableCell(withIdentifier: "reuseIdentifier", for: indexPath) let cell = UITableViewCell () cell.textLabel?.text = "test" return cell } /* // Override to support conditional editing of the table view. override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool { // Return false if you do not want the specified item to be editable. return true } */ /* // Override to support editing the table view. override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) { if editingStyle == .delete { // Delete the row from the data source tableView.deleteRows(at: [indexPath], with: .fade) } else if editingStyle == .insert { // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view } } */ /* // Override to support rearranging the table view. override func tableView(_ tableView: UITableView, moveRowAt fromIndexPath: IndexPath, to: IndexPath) { } */ /* // Override to support conditional rearranging of the table view. override func tableView(_ tableView: UITableView, canMoveRowAt indexPath: IndexPath) -> Bool { // Return false if you do not want the item to be re-orderable. return true } */ // MARK: - Navigation // In a storyboard-based application, you will often want to do a little preparation before navigation override func prepare(for segue: UIStoryboardSegue, sender: Any?) { // Get the new view controller using segue.destination. // Pass the selected object to the new view controller. // getPrice() print("test_segue") if let quoteViewController = segue.destination as? QuoteDetailViewController{ if let selectedQuote = sender as? String { quoteViewController.title = selectedQuote } } } } Many thanks
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Activity
Mar ’25
Why does Array.contains cause a compile-time error when comparing an optional value with a non-optional value in Swift?
I’m working with Swift and ran into an issue when using the contains(_:) method on an array. The following code works fine: let result = ["hello", "world"].contains(Optional("hello")) // ✅ Works fine But when I try to use the same contains method with the array declared in a separate variable, I get a compile-time error: let stringArray = ["hello", "world"] let result = stringArray.contains(Optional("hello")) // ❌ Compile-time error Both examples seem conceptually similar, but the second one causes a compile-time error, while the first one works fine. I understand that when comparing an optional value (Optional("hello")) with a non-optional value ("hello"), Swift automatically promotes the non-optional value to an optional (i.e., "hello" becomes Optional("hello")). 🔗 reference What I don’t understand is why the first code works but the second one doesn’t, even though both cases involve comparing an optional value with a non-optional value. I know that there are different ways to resolve this, like using nil coalescing or optional binding, but what I’m really looking for is a detailed explanation of why this issue occurs at the compile-time level. Can anyone explain the underlying reason for this behavior?
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147
Activity
Mar ’25
Help!
I am a Chinese student beginner ,do you have any advice for me to learn swift?I don't know how to start it.Please!🙏
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190
Activity
Apr ’25
Crash when Mutating Array of Tuples with String Property from Multiple Threads
Hi Apple Developer Community, I'm facing a crash when updating an array of tuples from both a background thread and the main thread simultaneously. Here's a simplified version of the code in a macOS app using AppKit: class ViewController: NSViewController { var mainthreadButton = NSButton(title: "test", target: self, action: nil) var numbers = Array(repeating: (dim: Int, key: String)(0, "default"), count: 1000) override func viewDidLoad() { super.viewDidLoad() view.addSubview(mainthreadButton) mainthreadButton.translatesAutoresizingMaskIntoConstraints = false mainthreadButton.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true mainthreadButton.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true mainthreadButton.widthAnchor.constraint(equalToConstant: 100).isActive = true mainthreadButton.heightAnchor.constraint(equalToConstant: 100).isActive = true mainthreadButton.target = self mainthreadButton.action = #selector(arraytest(_:)) } @objc func arraytest(_ sender: NSButton) { print("array update started") // Background update DispatchQueue.global().async { for i in 0..&lt;1000 { self.numbers[i].dim = i } } // Main thread update var sum = 0 for i in 0..&lt;1000 { numbers[i].dim = i + 1 sum += numbers[i].dim print("test \(sum)") } mainthreadButton.title = "test = \(sum)" } } This results in a crash with the following message: malloc: double free for ptr 0x136040c00 malloc: *** set a breakpoint in malloc_error_break to debug What's interesting: This crash only happens when the tuple contains a String ((dim: Int, key: String)) If I change the tuple type to use two Int values ((dim: Int, key: Int)), the crash does not occur My Questions: Why does mutating an array of tuples containing a String crash when accessed from multiple threads? Why is the crash avoided when the tuple contains only primitive types like Int? Is there an underlying memory management issue with value types containing reference types like String? Any explanation about this behavior and best practices for thread-safe mutation of such arrays would be much appreciated. Thanks in advance!
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Activity
Apr ’25
suggestion for the swift programming language
and yeah, swift vaguely is reminiscent of a programming language I developed, but I want swift To do return if (var blah:Int32 == 43){ blah = blah2; } your welcome !! thank me on my new accounting job lol =/ basically I want to return conditional statements for a private reason
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186
Activity
Apr ’25
Actors with Combine publishers as properties.
Is it ok for an Actor type to have a Publisher as a property to let others observe changes over time? Or use the @Published property wrapper to achieve this? actor MyActor { var publisher = PassthroughSubject<Int, Never>() var data: Int { didSet { publisher.send(data) } } ... } // Usage var tasks = Set<AnyCancellable>() let actor = MyActor() Task { let publisher = await actor.publisher publisher.sink { print($0) }.store(in: &tasks) } This seems like this should be acceptable. I would expect a Publisher to be thread safe, and as long as the Output is a value type things should be fine. I have been getting random EXC_BAD_ACCESS errors when using this approach. But turning on the address sanitizer causes these crashes to go away. I know that isn't very specific but I wanted to start by seeing if this type of pattern is ok to do.
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Activity
Apr ’25
Open any Swift view from C++
I've narrowed down my question after many rabbit holes - how can C++ code open any view in Swift. I can call functions in swift from C++ (works great), but not async or main actor (or actor at all) functions. And if I'm not mistaken all views are actors if not main actors? When calling from C+ I think its necessary that the first view be the main actor? I've implemented the code from the WWDC23 C++ interop video (Zoe's image picker) where I made a view in a struct, and just want to call it and let the view do the work. The compiler immediately gives me 'cannot expose main actors to C++'. If I'm not mistaken, doesn't this block the opening of any kind of swift view from C++? Hopefully I'm missing something obvious, which is likely :) In Zoe's code was his entry point into the program still Swift and not actually C++ app? Thanks! Thanks!
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160
Activity
May ’25
'init(coordinateRegion:interactionModes:showsUserLocation:userTrackingMode:annotationItems:annotationContent:)' was deprecated in iOS 17.0: Use Map initializers that t
I am currently encountering two deprecated errors in my code. Could someone please identify the issues with the code? Errors: 'init(coordinateRegion:interactionModes:showsUserLocation:userTrackingMode:annotationItems:annotationContent:)' was deprecated in iOS 17.0: Use Map initializers that take a MapContentBuilder instead. 'MapAnnotation' was deprecated in iOS 17.0: Use Annotation along with Map initializers that take a MapContentBuilder instead. Code: // MARK: - Stores Map (Dynamic) struct StoresMapView: View { @State private var storeLocations: [StoreLocation] = [] @State private var region = MKCoordinateRegion( center: CLLocationCoordinate2D(latitude: -31.95, longitude: 115.86), span: MKCoordinateSpan(latitudeDelta: 0.5, longitudeDelta: 0.5) ) var body: some View { Map(coordinateRegion: $region, interactionModes: .all, annotationItems: storeLocations) { store in MapAnnotation(coordinate: CLLocationCoordinate2D(latitude: store.latitude, longitude: store.longitude)) { VStack(spacing: 4) { Image(systemName: "leaf.circle.fill") .font(.title) .foregroundColor(.green) Text(store.name) .font(.caption) .fixedSize() } } } .onAppear(perform: loadStoreData) .navigationTitle("Store Locator") } private func loadStoreData() { guard let url = URL(string: "https://example.com/cop092/StoreLocations.json") else { return } URLSession.shared.dataTask(with: url) { data, _, _ in if let data = data, let decoded = try? JSONDecoder().decode([StoreLocation].self, from: data) { DispatchQueue.main.async { self.storeLocations = decoded if let first = decoded.first { self.region.center = CLLocationCoordinate2D(latitude: first.latitude, longitude: first.longitude) } } } }.resume() } }
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Activity
May ’25
Swift Concurrency: Calling @MainActor Function from Protocol Implementation in Swift 6
I have a Settings class that conform to the TestProtocol. From the function of the protocol I need to call the setString function and this function needs to be on the MainActor. Is there a way of make this work in Swift6, without making the protocol functions running on @MainActor The calls are as follows: class Settings: TestProtocol{ var value:String = "" @MainActor func setString( _ string:String ){ value = string } func passString(string: String) { Task{ await setString(string) } } } protocol TestProtocol{ func passString( string:String ) }
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Activity
May ’25
Issue with Swift 6 migration issues
We are migrating to swift 6 from swift 5 using Xcode 16.2. we are getting below errors in almost each of our source code files : Call to main actor-isolated initializer 'init(storyboard:bundle:)' in a synchronous non isolated context Main actor-isolated property 'delegate' can not be mutated from a nonisolated context Call to main actor-isolated instance method 'register(cell:)' in a synchronous nonisolated context Call to main actor-isolated instance method 'setup()' in a synchronous nonisolated context Few questions related to these compile errors. Some of our functions arguments have default value set but swift 6 does not allow to set any default values. This requires a lot of code changes throughout the project. This would be lot of source code re-write. Using annotations like @uncheck sendable , @Sendable on the class (Main actor) name, lot of functions within those classes , having inside some code which coming from other classes which also showing main thread issue even we using @uncheck sendable. There are so many compile errors, we are still seeing other than what we have listed here. Fixing these compile errors throughout our project, would be like a re-write of our whole application, which would take lot of time. In order for us to migrate efficiently, we have few questions where we need your help with. Below are the questions. Are there any ways we can bypass these errors using any keywords or any other way possible? Can Swift 5 and Swift 6 co-exist? so, we can slowly migrate over a period of time.
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Activity
Jun ’25
Import Java Module into Swift
Is there any way that I can import a Java module for use from Swift?
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Jun ’25