Is there an easy way to clear the cinterop cache without changing the .def file? I just updated my system and some /usr/include headers have changed but as long as the .def file isn't changed it re-uses the previous generated klib. If I change the .def it regenerates, but if I revert my local .def change, and re-run my generator, cinterop seems to revert back to the old cached version.

Ever since I started using K/N, I see the Gradle "Damon will be stopped at the end of the build after running out of JVM memory" a lot, even when I'm just compiling fairly small projects.

i have a c function that accepts something like

some_struct_t**

and the function populates the array at the given pointer. i’ve seen docs on how to create an array and get a pointer to it in K/N but since i don’t know the size of it ahead of time i’m not sure how to create it. in c i would just pass a pointer to such an empty array but i’m not sure what the kotlin equivalent is

Hello, does anybody have any examples of using

stat

or

nftw

? I'm attempting to work from the docs at https://linux.die.net/man/3/nftw, but I'm a little lost.

// ...
    val dir = "/tmp"
    nftw(dir, ::printEntry, 50, FTW_PHYS)
}

fun printEntry(path: String, ??? ) {

}

Further question on the above. I'm trying to see if a file is on the same device as the initial path that I look at; the st_dev that I'm getting back from stat seems to be identical across all devices. (details in thread)

Does anyone here tried already to use GNU gettext with K/N? Is there already some library providing bindings?

Anyone here a Nix fan & able to get Kotlin/Native linux builds working? Here is what I tried for my

shell.nix

with import <nixpkgs> {};
mkShell {
  NIX_LD_LIBRARY_PATH = lib.makeLibraryPath [
    stdenv.cc.cc.lib
    zlib
    libclang.lib
  ];
  NIX_LD = lib.fileContents "${<http://stdenv.cc|stdenv.cc>}/nix-support/dynamic-linker";
}

Can anyone help me further? I want to create a CLI tool in Kotlin-native and use in from Docker. Locally on my mac I can build and use the tool but I get problems when I build it with Docker. On my M1 Mac I get:

Caused by: org.gradle.internal.resolve.ModuleVersionNotFoundException: Could not find :kotlin-native-prebuilt-linux-aarch64:1.8.0.
Searched in the following locations:
   - <https://download.jetbrains.com/kotlin/native/builds/releases/1.8.0/linux-aarch64/kotlin-native-prebuilt-linux-aarch64-1.8.0.tar.gz>

I test it with a basic hallo world native application. Changed the

build.gradle.kts

to support my M1:

...
kotlin {
    val hostOs = System.getProperty("os.name")
    val arch = System.getProperty("os.arch")
    val isMingwX64 = hostOs.startsWith("Windows")
    val nativeTarget = when {
        hostOs == "Mac OS X" && arch == "aarch64" -> macosArm64("native")
        hostOs == "Mac OS X" -> macosX64("native")
        hostOs == "Linux" && arch == "aarch64" -> linuxArm64("native")
        hostOs == "Linux" -> linuxX64("native")
        isMingwX64 -> mingwX64("native")
        else -> throw GradleException("Host OS is not supported in Kotlin/Native.")
    }

Dockerfile

FROM gradle:8-jdk17-focal AS builder
COPY . /app
WORKDIR /app
RUN gradle build --warning-mode summary --stacktrace --scan

FROM ubuntu:focal
COPY --from=builder /app/build/bin/native/releaseExecutable ./
CMD ["./clean-native.kexe"]

It looks like the on the latest release linux-aarch64 does not exist. Is this possible and how could I do this?

Hi 👋, I have a kotlin project which has 2 dependencies which have a couple of same gradle tasks. Therefore I end up in

A problem occurred configuring project ':shared'.
> Failed to notify project evaluation listener.
   > Cannot add task 'xxx' as a task with that name already exists.

Can you please tell me how to explicitly exclude/disable a task for a dependency?

Hi, I asked that question already in #multiplatform, but maybe #kotlin-native is better suited: One question regarding AndroidStudio (in my case Electic Eel 2022.1.1 Patch 2) and launching ios-app from KMM-Project: Is somebody sometimes also facing the problem that the whole system (in my case MacOS Ventura 13.0.1: Chip: Apple M1 Max) gets killed while launching iosApp from AndroidStudio via the RunConfiguration aka play/debug-buttons?

Can anyone confirm if

char**

in C is represented as

CPointerVar<Char>

in kotlin?

Hello! I am currently writing my master’s thesis where I am comparing the performance of iOS applications developed in Kotlin Multiplatform Mobile vs native Swift applications. To be able to compare them I need to optimize both compilations so that they are as comparable as possible. I have managed to optimize the Kotlin/Native compilation by adding the compiler option

-opt

to the

freeCompilerArgs

list in the

build.gradle.kts

file in the shared folder (execution time went from approx 1.4 to 0.33). Now, I have some questions: 1. What kinds of optimizations are made by adding

-opt

? (such as for instance “constant folding”, “dead code removal” etc.) 2. Are there other optimizations that I can apply? I would appreciate any input or suggestions that you have as I struggle to find documentation or information on this. If you know any good resources, let me know! Thanks!

How can I convert

List<T>

(where

T

is a

CStructVar

) to

CValuesRef<T>

?

My question is not very specific to kotlin-native, but since I'm writing a KN library I would like to get some feedback from the people here: In the bindings I'm writing I'm wrapping lots of C functions that can "throw" errors. I would like to avoid having multiple signatures for every "throwing" method so I need to choose which signature I'm going to generate: I can either return a

Result<T>

to make the the error explicit in the signature, or I can add a

@Throws

annotation and just throw the exception. Currently I'm favoring the

Result<T>

approach but it has some issues (like the Exception type not being generic). Any opinions on this?

Is there some option to expose module A cinterops to be visible to module B that consumes module A?

After updating from Kotlin 1.8.10 to 1.8.20, I ran into this error. Any idea if there's a workaround?

Hello! I have found in the documentation, some statements, like:

Keep your library up-to-date. If you’re a library author, updating to the new Kotlin version is extremely important. Using older versions could block your users from updating Kotlin in their projects.

and

Change the versions of dependencies to EAP ones. The EAP version of Kotlin may not work with the libraries of the previously released version.

Does it mean that some Kotlin versions are not compatible or not ABI stable? Thanks

I am getting a weird error with trying to use cinterop in kotlin native. I am using a C++ static library with a C header file, with extern "C" if compiled with C++, that uses another of my cinterop libraries inside it. Full error in the thread

lld-link: warning: ignoring unknown argument: -exclude-symbols:main_test
lld-link: error: -exclude-symbols:main_test is not allowed in .drectve

Hi! How does Kotlin Native handle C structure padding? As far as I know there is no official standard for this. My application would handle a large amount of binary data in a predefined data structure. In C/C++ I created structs that map to the data and I used the pragma pack to avoid the compiler shuffling things around. I might work around the issue by handling specifics manually, but it would be very nice to know what's going on actually. Thanks

Hi, Did any of you seen this weird error with cinterop & native Apple framework ->

Type mismatch: inferred type is suntrix.kmp.firebase.FIRApp but objcnames.classes.FIRApp was expected

? The generated Kotlin “header” looks weird (see

installationsWithApp()

)

public open expect class FIRInstallationsMeta : platform.darwin.NSObjectMeta {
    protected constructor() { /* compiled code */ }

    @kotlin.commonizer.ObjCCallable @kotlin.Deprecated public open external expect fun alloc(): suntrix.kmp.firebase.installations.FIRInstallations? { /* compiled code */ }

    @kotlin.commonizer.ObjCCallable @kotlin.Deprecated public open external expect fun allocWithZone(zone: kotlinx.cinterop.CPointer<cnames.structs._NSZone>?): suntrix.kmp.firebase.installations.FIRInstallations? { /* compiled code */ }

    @kotlin.commonizer.ObjCCallable public open external expect fun installations(): suntrix.kmp.firebase.installations.FIRInstallations { /* compiled code */ }

    @kotlin.commonizer.ObjCCallable public open external expect fun installationsWithApp(application: objcnames.classes.FIRApp): suntrix.kmp.firebase.installations.FIRInstallations { /* compiled code */ }

    @kotlin.commonizer.ObjCCallable public open external expect fun new(): suntrix.kmp.firebase.installations.FIRInstallations? { /* compiled code */ }
}

Some cool things are brewing for K/N UI world. Here's a little demo of GTK4 app on LinuxX64 build with kotlin native! All the credits go to @vbsteven and friends. Keep an eye out! (all the code in the thread)

Anyone have tried doing realtime ray tracing using opengl or vulkun in KN?

I’m trying to create a native CLI utility that uses different Ktor engine per platform, and I’m starting with Mac. The project has a common “nativeMain” module for all platforms. So I have modified my build like this:

kotlin {
...
    val nativeTarget = when {
        hostOs == "Mac OS X" -> macosX64("native")
        hostOs == "Linux" -> linuxX64("native")
...
    }

...
    sourceSets {
        val nativeMain by getting {
            dependencies {
                implementation("org.jetbrains.kotlinx:kotlinx-cli:0.3.5")
            }
        }

        val nativeMac by creating {
            dependsOn(nativeMain)
            dependencies {
                implementation("io.ktor:ktor-client-darwin:$ktorVersion")
            }
        }
    }
}

And I’m getting

The Kotlin source set nativeMac was configured but not added to any Kotlin compilation. You can add a source set to a target's compilation by connecting it with the compilation's default source set using 'dependsOn'.
See <https://kotlinlang.org/docs/reference/building-mpp-with-gradle.html#connecting-source-sets>

But I can’t figure how to “add a source set to a target’s compilation”, also the link in the warning goes to nowhere.

Hello! Could somebody answer me, why “is T”( T is type Parameter) don’t work due to type erasure, but “as T” work fine in the same conditions(only case is unchecked)? I thought due to type erasure both of them shouldn’t work, as T type will not be available in runtime( for example in function call) Thanks

Hello, newbie to native world. What is the best way to handle obj c functions that throws an exception. Basically they carry an extra param with a type

CPointer<ObjCObjectVar>NSError?>>

. Using try and catch is not useful and I don't want to pass in null

value classes aren’t implemented across the objc interop bridge. Right now we get those values upcast to

Any

in swift. Is there any reason K/N hasn’t decided to just box the value across the bridge?

Have an odd one - getting an issue while compiling a sharedLib() binary for macosArm64(“native”). I am getting this from doing a

./gradlew linkNative

It’s obviously something to do with the header files used from the toolchain but I have no idea how to specify anything different.

2 errors generated.

 * Source files:
 * Compiler version info: Konan: 1.7.21 / Kotlin: 1.7.21
 * Output kind: DYNAMIC

e: org.jetbrains.kotlin.konan.KonanExternalToolFailure: The /Users/ahelbling/.konan/dependencies/apple-llvm-20200714-macos-aarch64-essentials/bin/clang++ command returned non-zero exit code: 1.
output:
In file included from /var/folders/08/mqm71ljs6qsct07_r9qxd9vc0000gn/T/konan_temp15784896127495882400/api.cpp:165:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX13.3.sdk/usr/include/c++/v1/exception:84:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX13.3.sdk/usr/include/c++/v1/cstdlib:135:9: error: no member named 'at_quick_exit' in the global namespace
using ::at_quick_exit _LIBCPP_USING_IF_EXISTS;
      ~~^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX13.3.sdk/usr/include/c++/v1/cstdlib:136:9: error: no member named 'quick_exit' in the global namespace
using ::quick_exit _LIBCPP_USING_IF_EXISTS;
      ~~^
2 errors generated.

What is the best way to have the cinterop task re-run if a binary it links against changes? I'm trying to implement something 'similar' to jvm's resources folder, where I can specify a folder and a task I wrote runs ld to create an object file with the binary data, then use cinterop to add the binary to my code. This works fine, but I have to run a clean after every time my resources change.

hi, I’m trying to convert some C code (full code in 🧵) to Kotlin Native

Model model = LoadModel("resources/model.obj")
Texture2D texture = LoadTexture("resources/texture.png");
model.materials[0].maps[MATERIAL_MAP_DIFFUSE].texture = texture; // Set map diffuse texture

I can get close, but for some reason the generated cinterop Kotlin code has texture as a

val

, not a

var

val model: CValue<Model> = LoadModel("resources/model.obj")
val texture: CValue<Texture> = LoadTexture("resources/texture.png")

model.useContents {
  // model.materials[0].maps[MATERIAL_MAP_DIFFUSE].texture = texture
  materials!![0].maps!![MATERIAL_MAP_DIFFUSE].texture = texture // ERROR val cannot be reassigned
}

any hints are appreciated!

Has anyone managed to statically link their c file into kn executable? Looking for examples as my experiments have all been failing so far