This topic area is about the programming languages themselves, not about any specific API or tool. If you have an API question, go to the top level and look for a subtopic for that API. If you have a question about Apple developer tools, start in the Developer Tools & Services topic.
For Swift questions:
If your question is about the SwiftUI framework, start in UI Frameworks > SwiftUI.
If your question is specific to the Swift Playground app, ask over in Developer Tools & Services > Swift Playground
If you’re interested in the Swift open source effort — that includes the evolution of the language, the open source tools and libraries, and Swift on non-Apple platforms — check out Swift Forums
If your question is about the Swift language, that’s on topic for Programming Languages > Swift, but you might have more luck asking it in Swift Forums > Using Swift.
General:
Forums topic: Programming Languages
Swift:
Forums subtopic: Programming Languages > Swift
Forums tags: Swift
Developer > Swift website
Swift Programming Language website
The Swift Programming Language documentation
Swift Forums website, and specifically Swift Forums > Using Swift
Swift Package Index website
Concurrency Resources, which covers Swift concurrency
How to think properly about binding memory Swift Forums thread
Other:
Forums subtopic: Programming Languages > Generic
Forums tags: Objective-C
Programming with Objective-C archived documentation
Objective-C Runtime documentation
Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
Dive into the world of programming languages used for app development.
Selecting any option will automatically load the page
Post
Replies
Boosts
Views
Activity
The speaker mentions there is "less risk of creating a retain cycle in when capturing self in a closure within a value type", such as a SwiftUI view struct.
Can you elaborate on when this could actually occur?
Thanks!
Will Apple continue to support it, or will we wake up one day to find that Swift is the only viable language?It's a serious question. Careers depend on it. I don't accept the "No comment" approach that Apple usually takes. It's cruel.I'm willing to put the time into learning Swift if I have to. I'm not going to do it if I don't. I want to know.Frank
Hello, everyone!
Help me please to find answer. I have two applications: App-1 with share extension and App-2 without it. From the second app I can open share extension via UIActivityViewController. But I need this extension in the second application to open immediately by pressing a button, and not through UIActivityViewController. Can I do this?
Hey all!
in my personal quest to make future proof apps moving to Swift 6, one of my app has a problem when setting an artwork image in MPNowPlayingInfoCenter
Here's what I'm using to set the metadata
func setMetadata(title: String? = nil, artist: String? = nil, artwork: String? = nil) async throws {
let defaultArtwork = UIImage(named: "logo")!
var nowPlayingInfo = [
MPMediaItemPropertyTitle: title ?? "***",
MPMediaItemPropertyArtist: artist ?? "***",
MPMediaItemPropertyArtwork: MPMediaItemArtwork(boundsSize: defaultArtwork.size) { _ in
defaultArtwork
}
] as [String: Any]
if let artwork = artwork {
guard let url = URL(string: artwork) else { return }
let (data, response) = try await URLSession.shared.data(from: url)
guard (response as? HTTPURLResponse)?.statusCode == 200 else { return }
guard let image = UIImage(data: data) else { return }
nowPlayingInfo[MPMediaItemPropertyArtwork] = MPMediaItemArtwork(boundsSize: image.size) { _ in
image
}
}
MPNowPlayingInfoCenter.default().nowPlayingInfo = nowPlayingInfo
}
the app crashes when hitting
MPMediaItemPropertyArtwork: MPMediaItemArtwork(boundsSize: defaultArtwork.size) { _ in
defaultArtwork
}
or
nowPlayingInfo[MPMediaItemPropertyArtwork] = MPMediaItemArtwork(boundsSize: image.size) { _ in
image
}
commenting out these two make the app work again.
Again, no clue on why.
Thanks in advance
We are getting a crash _dispatch_assert_queue_fail when the cancellationHandler on NSProgress is called.
We do not see this with iOS 17.x, only on iOS 18. We are building in Swift 6 language mode and do not have any compiler warnings.
We have a type whose init looks something like this:
init(
request: URLRequest,
destinationURL: URL,
session: URLSession
) {
progress = Progress()
progress.kind = .file
progress.fileOperationKind = .downloading
progress.fileURL = destinationURL
progress.pausingHandler = { [weak self] in
self?.setIsPaused(true)
}
progress.resumingHandler = { [weak self] in
self?.setIsPaused(false)
}
progress.cancellationHandler = { [weak self] in
self?.cancel()
}
When the progress is cancelled, and the cancellation handler is invoked. We get the crash. The crash is not reproducible 100% of the time, but it happens significantly often. Especially after cleaning and rebuilding and running our tests.
* thread #4, queue = 'com.apple.root.default-qos', stop reason = EXC_BREAKPOINT (code=1, subcode=0x18017b0e8)
* frame #0: 0x000000018017b0e8 libdispatch.dylib`_dispatch_assert_queue_fail + 116
frame #1: 0x000000018017b074 libdispatch.dylib`dispatch_assert_queue + 188
frame #2: 0x00000002444c63e0 libswift_Concurrency.dylib`swift_task_isCurrentExecutorImpl(swift::SerialExecutorRef) + 284
frame #3: 0x000000010b80bd84 MyTests`closure #3 in MyController.init() at MyController.swift:0
frame #4: 0x000000010b80bb04 MyTests`thunk for @escaping @callee_guaranteed @Sendable () -> () at <compiler-generated>:0
frame #5: 0x00000001810276b0 Foundation`__20-[NSProgress cancel]_block_invoke_3 + 28
frame #6: 0x00000001801774ec libdispatch.dylib`_dispatch_call_block_and_release + 24
frame #7: 0x0000000180178de0 libdispatch.dylib`_dispatch_client_callout + 16
frame #8: 0x000000018018b7dc libdispatch.dylib`_dispatch_root_queue_drain + 1072
frame #9: 0x000000018018bf60 libdispatch.dylib`_dispatch_worker_thread2 + 232
frame #10: 0x00000001012a77d8 libsystem_pthread.dylib`_pthread_wqthread + 224
Any thoughts on why this is crashing and what we can do to work-around it? I have not been able to extract our code into a simple reproducible case yet. And I mostly see it when running our code in a testing environment (XCTest). Although I have been able to reproduce it running an app a few times, it's just less common.
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.
Hello
I'm using this sdk DeclaredAgeRange to get the user age range
When I'm doing in debug mode using sandbox account it is working as expected and I can get the user age range
But when I tried in TestFlight build using sandbox account it is not working and it is always return the age range 18+ and also isEligibleForAgeFeatures API is always returning false
Any advise on this?
Topic:
Programming Languages
SubTopic:
Swift
Recently I updated to Xcode 14.0. I am building an iOS app to convert recorded audio into text. I got an exception while testing the application from the simulator(iOS 16.0).
[SpeechFramework] -[SFSpeechRecognitionTask handleSpeechRecognitionDidFailWithError:]_block_invoke Ignoring subsequent recongition error: Error Domain=kAFAssistantErrorDomain Code=1101 "(null)"
Error Domain=kAFAssistantErrorDomain Code=1107 "(null)"
I have to know what does the error code means and why this error occurred.
Hey all!
During the migration of a production app to swift 6, I've encountered a problem: when hitting the UNUserNotificationCenter.current().requestAuthorization the app crashes.
If I switch back to Language Version 5 the app works as expected.
The offending code is defined here
class AppDelegate: NSObject, UIApplicationDelegate {
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
FirebaseApp.configure()
FirebaseConfiguration.shared.setLoggerLevel(.min)
UNUserNotificationCenter.current().delegate = self
let authOptions: UNAuthorizationOptions = [.alert, .badge, .sound]
UNUserNotificationCenter.current().requestAuthorization(options: authOptions) { _, _ in }
application.registerForRemoteNotifications()
Messaging.messaging().delegate = self
return true
}
}
The error is depicted here:
I have no idea how to fix this.
Any help will be really appreciated
thanks in advance
Topic:
Programming Languages
SubTopic:
Swift
Tags:
User Notifications
Notification Center
Concurrency
Getting this error several times when presenting a modal window over my splitview window when running it on my Mac using Swift/Mac Catalyst in XCode 14.2. When I click the Cancel button in the window then I get Scene destruction request failed with error: (null) right after an unwind segue.
2023-07-04 16:50:45.488538-0500 Recipes[27836:1295134] [WindowHosting] UIScene property of UINSSceneViewController was accessed before it was set.
2023-07-04 16:50:45.488972-0500 Recipes[27836:1295134] [WindowHosting] UIScene property of UINSSceneViewController was accessed before it was set.
2023-07-04 16:50:45.496702-0500 Recipes[27836:1295134] [WindowHosting] UIScene property of UINSSceneViewController was accessed before it was set.
2023-07-04 16:50:45.496800-0500 Recipes[27836:1295134] [WindowHosting] UIScene property of UINSSceneViewController was accessed before it was set.
2023-07-04 16:50:45.994147-0500 Recipes[27836:1295134] Unbalanced calls to begin/end appearance transitions for <UINavigationController: 0x7f7fdf068a00>.
bleep
2023-07-04 16:51:00.655233-0500 Recipes[27836:1297298] Scene destruction request failed with error: (null)
I don't quite understand what all all this means. (The "bleep" was a debugging print code I put in the unwind segue). I'm working through Apple's Mac Catalyst tutorial but it seems to be riddled with bugs and coding issues, even in the final part of the completed app which I dowmloaded and ran. I don't see these problems on IPad simulator.
I don't know if it's because Catalyst has problems itself or there's something else going on that I can fix myself. Any insight into these errors would be very much appreciated!
PS: The app seems to run ok on Mac without crashing despite the muliple issues
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!
Is there a swift6 manual that will teach me how to code in swift?
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.
Topic:
Programming Languages
SubTopic:
Swift
I’m aware that Xcode version 26 beta 3 provides an option to enable Swift’s Approachable Concurrency feature at the project level. However, I’d like to achieve the same for a Swift Package. Could you please advise on how to enable Approachable Concurrency support specifically for a Swift Package?
Hello, I have a problem with the .onMove function. I believe I have set everything up properly. However, the moving does not seem to be working correctly. When I try to move the item, it is highlighted first, as it is supposed to be. Then, while I am moving it through the list, it disappears for some reason, and at the end of the move, it comes back to its initial place. (I use iOS 16.0 minimum, so I don't have to include the EditButton(). It works the same in the edit mode tho)
import SwiftUI
struct Animal: Identifiable {
var id = UUID()
var name: String
}
struct ListMove: View {
@State var animals = [Animal(name: "Dog"), Animal(name: "Cat"), Animal(name: "Cow"), Animal(name: "Goat"), Animal(name: "Chicken")]
var body: some View {
List {
ForEach(animals) { animal in
Text(animal.name)
}
.onMove(perform: move)
}
}
func move(from source: IndexSet, to destination: Int) {
animals.move(fromOffsets: source, toOffset: destination)
}
}
#Preview {
ListMove()
}
Hey there-
I'm having a quite interesting bug on Swift Playgrounds.
I am trying to run my app with this following code snippet which does not compile on Swift Playgrounds, yet compiles on XCode (note: this is a Swift Playground app)
if #available(iOS 18.0, *) {
//simple function to get the indices of other items that have the same date as the "date" variable
let indices = data!.indices(where: { item in
let sameMonth = Calendar.current.component(.month, from: item.time) == Calendar.current.component(.month, from: date)
let sameYear = Calendar.current.component(.year, from: item.time) == Calendar.current.component(.year, from: date)
let sameDay = Calendar.current.component(.day, from: item.time) == Calendar.current.component(.year, from: date)
return sameDay && sameMonth && sameYear
})
However, the indices(where:) codeblock seems to stop the app from compiling (ONLY on Swift Playgrounds - it works perfectly fine on XCode).
I am getting the following error:
Cannot call value of non-function type 'Range<Array<Int>.Index>' (aka 'Range<Int>')
Please let me know if you have any insight regarding this issue.
-ColoredOwl
Topic:
Programming Languages
SubTopic:
Swift
Tags:
Swift Playground
Xcode
Playground Support
SwiftUI
macOS Tahoe ships with Ruby 2.6.10 which was End Of Life in April 2022 (https://www.ruby-lang.org/en/downloads/branches/). How can I either upgrade it to Ruby 3.4.7 or delete it, so that my mac meets minimum cybersecurity requirements?
I use rbenv for more recent versions of Ruby at the moment so don't need any suggestions on how to do add them, I just need rid of the dangerously out of date system Ruby, thanks.
Topic:
Programming Languages
SubTopic:
General
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
"the compiler is unable to type-check this expression in reasonable time; try breaking up the expression into distinct sub-expressions" ...... it killing me !!!!
I want to understand what the recommended way is for string interoperability between swift and c++. Below are the 3 ways to achieve it. Approach 2 is not allowed at work due to restrictions with using std libraries.
Approach 1:
In C++:
char arr[] = "C++ String";
void * cppstring = arr;
std::cout<<"before:"<<(char*)cppstring<<std::endl; // C++ String
// calling swift function and passing the void buffer to it, so that swift can update the buffer content
Module1::SwiftClass:: ReceiveString (cppstring, length);
std::cout<<"after:"<<(char*)cppstring<<std::endl; // SwiftStr
In Swift:
func ReceiveString (pBuffer : UnsafeMutableRawPointer , pSize : UInt ) -> Void
{
// to convert cpp-str to swift-str:
let swiftStr = String (cString: pBuffer.assumingMemoryBound(to: Int8.self));
print("pBuffer content: \(bufferAsString)");
// to modify cpp-str without converting:
let swiftstr:String = "SwiftStr"
_ = swiftstr.withCString { (cString: UnsafePointer<Int8>) in
pBuffer.initializeMemory(as: Int8.self, from: cString, count: swiftstr.count+1)
}
}
Approach 2:
The ‘String’ type returned from a swift function is received as ‘swift::String’ type in cpp. This is implicitly casted to std::string type. The std::string has the method available to convert it to char *.
void
TWCppClass::StringConversion ()
{
// GetSwiftString() is a swift call that returns swift::String which can be received in std::string type
std::string stdstr = Module1::SwiftClass::GetSwiftString ();
char * cstr = stdstr.data ();
const char * conststr= stdstr.c_str ();
}
Approach 3:
The swift::String type that is obtained from a swift function can be received in char * by directly casting the address of the swift::String. We cannot directly receive a swift::String into a char *.
void
TWCppClass::StringConversion ()
{
// GetSwiftString() is a swift call that returns swift::String
swift::String swiftstr = Module1::SwiftClass::GetSwiftString ();
// obtaining the address of swift string and casting it into char *
char * cstr = (char*)&swiftstr;
}