I'm getting a linker error after declaring a function in my .def file and using it in Kotlin:

Undefined symbols for architecture x86_64:
  "_OBJC_CLASS_$_CBLC4Document", referenced from:
      objc-class-ref in result.o
  "_c4db_getDoc", referenced from:
      _cocoapods_CouchbaseLite_c4db_getDoc_wrapper0 in result.o
ld: symbol(s) not found for architecture x86_64

The function

c4db_getDoc()

is implemented in the library here. Its declaration just isn't in the framework's public headers, which is why I added it as a custom definition. Its internal declaration is in this .h file. I've declared it this same way in the .def (along with the struct parameter types):

C4Document* c4doc_get(C4Database *database, C4String docID, bool mustExist, C4Error* outError);

Would the issue be that the implementation is in a .cc C++ file and Kotlin doesn't support C++ interop? If so, is there some way I could access this function?

Does Kotlin Native have a way to get Kotlin objects out of a callback as output? Below is the defined callback:

fun runFunction(argPtr: COpaquePointer?): Int = memScoped {
    val tmpCmd = argPtr?.asStableRef<Command>()?.get() ?: throw IllegalStateException("Command cannot be null")
    val argv =
        if (tmpCmd.args.isEmpty()) arrayOf(tmpCmd.filePath, "").toCStringArray(this)
        else arrayOf(tmpCmd.filePath, *tmpCmd.args.toTypedArray()).toCStringArray(this)
    val status = alloc<IntVar>()
    val fileDescriptors = allocArray<IntVar>(2)
    createPipe(fileDescriptors)
    val pid = fork()

    if (pid == 0) {
        close(fileDescriptors[READ_POS])
        dup2(fileDescriptors[WRITE_POS], STDOUT_FILENO)
        dup2(fileDescriptors[WRITE_POS], STDERR_FILENO)
        execvp(tmpCmd.filePath, argv)
    }

    close(fileDescriptors[WRITE_POS])
    val file = openFileDescriptor(fileDescriptors[READ_POS])
    tmpCmd.output += file.readLines(10u)
    file.close()
    wait_for_process(status.ptr)
    status.value
}

In the callback the command output is stored in tmpCmd as a StableRef ( https://kotlinlang.org/api/latest/jvm/stdlib/kotlinx.cinterop/-stable-ref/ ). Why isn't the changed state of the StableRef accessible outside of the callback?

With the Kotlin Native documentation there is an article that isn't applicable to all Kotlin Native targets: https://kotlinlang.org/docs/multiplatform-mobile-concurrency-overview.html This article (is iOS/mobile specific) should be moved somewhere else. Also the article's title should be renamed to Multiplatform Mobile Concurrency Overview.

Would appreciate any help on this, can't find anything about either error on the internet

I was trying out Kotlin native for the first time and I was wondering if a kexe file on Mac can be turned into a proper distributable CLI app for other people? Or is this not yet possible?

Is it not possible to declare additional

initWith...

functions (constructors) in an ObjC category in a .def file? I've had success declaring properties and functions that aren't in the public API of an ObjC class, but adding an

initWith...

function doesn't add the constructor definition (or the

@Deprecated initWith...

function that is usually generated with the constructor). For example, where

MyObjCClass

is previously declared in a public API header:

@interface MyObjCClass (Internal)
@property (nonatomic, readonly, nonnull) NSString *foo;
- (BOOL) isBar;
- (instancetype) initWithFoo: (NSString)foo bar: (BOOL)bar;
@end

Adds extension functions on the class definition, instead of modifying the class defined by the public API header:

expect val MyObjCClass.foo: NSInteger
@ObjCCallable external expect fun MyObjCClass.foo(): NSInteger
@ObjCCallable external expect fun MyObjCClass.isBar(): Boolean

There is nothing added for the

initWithFoo:bar:

constructor though.

Hey all, not sure if this is a known issue or not: I have a Kotlin interface hierarchy with something like this:

sealed interface MyCollectionClass {
  val collection: Collection<String>
}

data class MyListClass: MyCollectionClass {
  override val collection: List<String>
}

data class MySetClass: MyCollectionClass {
  override val collection: Set<String>
}

Within Kotlin, when we that our concrete type is a

MyListClass

, we also know that

collection

is of type

List<String>

But in Swift, even when we know we have an instance of

MyListClass

, the type of

collection

looks like a

Collection<String>

I think this is only the case with `sealed interface`s — `sealed class`es seem to be working as expected.

Can we have something like

macos()

instead of

macosX64() macosArm64()

like

ios()

in kotlin target config?

I've run into a blocker when trying to use kotlin native with my project. I created a ticket and a sample project to easily replicate it. Anybody know what may be wrong? https://youtrack.jetbrains.com/issue/KT-53282/Bad-params-issue-with-AudioQueue-on-iOS

Hey! 😊 Has anybody ever tried bluetooth socket programming (RFCOMM) with Kotlin Native? 🤔 I'm trying to implement this C-example (https://people.csail.mit.edu/albert/bluez-intro/x502.html) in Kotlin Native but it doesn't work. Everything is compiling fine and executing but the socket doesn't accept any connections. 🙁

Maybe I should add it here that I want to use libbluetooth.so (BlueZ-Stack). 😅

What would be the behavior of `pin()`ing a

ByteArray

and not `unpin()`ing it? Would this only prevent GC from relocating the memory, or would it cause a memory leak? My issue is with returning a native pointer to an internal

ByteArray

buffer as a stable reference, where the caller uses the pointer, but can't call

unpin()

after doing so.

I need to write a large int[] from C to a Kotlin IntArray in a performant way. Can I assume that an IntArray stores all values sequentially like a C int[] and memcpy the data to Pinned<IntArray>.addressOf(0), or could this break in future Kotlin Native releases?

Hello, World! I have a behavior difference when using the new memory manager or not with this very simple app (on Apple):

fun main() {
    runBlocking {
        withContext(Dispatchers.Main) {
            println("Hello, World!")
        }
    }
}

With the new memory manager enabled, the message is never printed, the thread seems to be stuck on

withContext

. I’m not sure if this is to be expected - something like

runBlocking

blocking the main thread and making dispatching ineffective? … But then again it feels like this should work, and also looks like a regression since it works with the old MM? 🤔 Any insight would be appreciated! 🙏 Repro project here.

I'm trying to use

platform.windows.LPWSTR? /* = kotlinx.cinterop.CPointer<platform.windows.WCHARVar /* = kotlinx.cinterop.UShortVarOf<kotlin.UShort> */>

for creating a https://docs.microsoft.com/en-us/windows/win32/api/winsvc/ns-winsvc-service_table_entrya struct. I'm stuck on the

lpServiceName

member, no idea how to obtain a value for it. Edit: maybe I got it.

lpServiceName = "MyString".wcstr.ptr

Why are functions exported as nullable `val`s? Or better, why the "macro" that gets replace with *A or *W is nullable? Any good reason?

I’m seeing an issue in Kotlin/Native where === is returning false for two variables that both point to same ObjC object (== works fine). Is this a known issue that === doesn’t compare pointers as expected when comparing ObjC objects? Or is my understanding of === equality missing something?

Unfortunately I can't tell you what's wrong, however, I would recommend creating a new issue in youtrack if you suspect a bug. There it will get the appropriate attention.

I don’t know that there’s a way to automatically convert, but I generally write a Boolean.toBool(): Int and a Int.toKBoolean(): Boolean and call these.

How does

AutofreeScope

and

Arena

work? do they automatically free the allocated memory when they are garbage collected, or is there some other mean to ensure native memory is freed if a kotlin object is garbage collected? We are currently wrapping a native library with a common code api and can not expose native memory management in the common code api.

static_kref_kotlin_Array args;
    args.pinned = NULL;
    syms->kotlin.root.main(args);

This works fine, but then predictably the program arguments are null Does anyone know how to pass the program arguments to Kotlin?

Bonjour, how do you distribute on multiple platforms a CLI tool written with Kotlin-native? Last time I checked it was easier to publish via Kotlin-JS on npm... Or do you use your custom brew tap?

Is anyone else seeing errors when generating GFM using Dokka where CPointer is used? It can’t correctly resolve any CPointer usages.

I have the following code, I'm wondering if theres some way I can shorten it into just a one line function such as

val windowAttributes dpy.getWindowAttributes(window)

val windowAttributes = nativeHeap.alloc<XWindowAttributes>() {
    XGetWindowAttributes(display.ptr, window, ptr)
}

// Do some stuff

nativeHeap.free(windowAttributes)

Are there any tips I can use to further reduce binary size? My release build is 4.3 mb and using the

strip

command on it shrinks it to 3.1 mb.

Hi all 🙂, I’m debugging my app in lldb, I would like to inspect variable which happens to be Map<String, String>. How would you do it? I loaded

konan_lldb.py

which helps interpretting non-basic structure and tells you little bit more then just

ObjHeader *

. But still, output of

v

command in lldb is this

(ObjHeader *) context = [keysArray: ..., valuesArray: ..., presenceArray: ..., hashArray: ..., keysView: ..., valuesView: ..., entriesView: ..., maxProbeDistance: ..., length: ..., hashShift: ..., _size: ..., isReadOnly: ...]

I would like to be able to print keys/values and I cant find the way to do that. Do anybody know how to do that? Thank you a lot 🙂

I am new to kotlin/native, especially in the iOS area of native development. I want to use the GRPC cocoapod dependency in my kotlin multiplatform project for my iOS target.

pod("gRPC-ProtoRPC", version = "~> 1.48", moduleName = "ProtoRPC")

However, my Gradle Task fails with fatal error: module 'ProtoRPC' not found I have tried the steps suggested in https://kotlinlang.org/docs/native-cocoapods.html#possible-issues-and-solutions. However, there was no module.modulemap in build/cocoapods/synthetic/Pods/gRPC-ProtoRPC. I found one in build/cocoapods/synthetic/Pods/Target Support Files/gRPC-ProtoRPC but that one says: framework module ProtoRPC. What is the easiest way of getting access to the Objective-C implementation of GRPC in Kotlin Multiplatform?

Can somebody point me to some documentation on how to use the Arena class? I can only find one mention of it in the docs here. https://kotlinlang.org/docs/mapping-struct-union-types-from-c.html#create-struct-and-union-as-cvaluesref-lt-t-gt I would like to understand the difference between it and using nativeHeap.

Hi 👋 . Looks like compiling a native lib with 1.7 requires consuming it with 1.7 (or we get a

Incompatible abi version

) 1. is that true? 2. could we allow consumption with 1.6 by adding

languageVersion = "1.6"

when compiling? Looks like this works for JVM but not for native?