kotlinlang #kotlin-native

@CName("Java_com_example_project_createString")
fun createString(env: kotlinx.cinterop.CPointer<JNIEnvVar>, instance: jobject):jstring?{
    val jniNativeInterface: JNINativeInterface = env.pointed.pointed!!
    val fNewStringUTF = jniNativeInterface.NewStringUTF!!
    val result = fNewStringUTF(env, "A test")
    return result
}

Where the 'A test' part wont work, because of it not being a jstring

salomonbrys

08/26/2019, 1:32 PM

Here's a follow-up to the thread about memory-model & my proposal for const classes to reduce multiplatform friction: https://medium.com/@timelzayus/designing-a-kotlin-memory-safe-mode-c76c06317c3e

🍿 5

💯 1

spierce7

08/26/2019, 4:39 PM

If you are in swift trying to access a Kotlin/native extension function - what does that look like? i.e. for JVM it’s expressed as a static utility / helper class.

napperley

08/27/2019, 2:34 AM

Added some additional definitions in the udev.def file, and encountered a linking error, where it isn't clear what is causing the error:

Task :cinteropUdevLinux FAILED
Exception in thread "main" java.lang.Error: /tmp/tmp360311134357443805.c:26:3: error: expected expression

JoakimForslund

08/27/2019, 9:14 AM

I'm somewhat confused. I converted a c-function, which ends up being this in kotlin:

public fun AES_CBC_encrypt_buffer(output: kotlinx.cinterop.CValuesRef<platform.posix.uint8_tVar /* = kotlinx.cinterop.UByteVarOf<platform.posix.uint8_t /* = kotlin.UByte */> */>?, input: kotlinx.cinterop.CValuesRef<platform.posix.uint8_tVar /* = kotlinx.cinterop.UByteVarOf<platform.posix.uint8_t /* = kotlin.UByte */> */>?, length: platform.posix.uint32_t /* = kotlin.UInt */, key: kotlinx.cinterop.CValuesRef<platform.posix.uint8_tVar /* = kotlinx.cinterop.UByteVarOf<platform.posix.uint8_t /* = kotlin.UByte */> */>?, iv: kotlinx.cinterop.CValuesRef<platform.posix.uint8_tVar /* = kotlinx.cinterop.UByteVarOf<platform.posix.uint8_t /* = kotlin.UByte */> */>?): kotlin.Unit { /* compiled code */ }

I'm trying to use it with the following setup: https://gist.github.com/Syrou/52db691f91928cb6aad6bcfd84bf5cff 1. Am I wrong in trying to use toCValues() method to translate the uByteArrays into what is specified in the method argument? 2. Am I using the buffer pinning wrong? Because each time I run this code I end up with a new result. This might be an error in the c-lib to start with, but I'm currently investigating if my implementation of the native code is wrong.

napperley

08/27/2019, 9:30 AM

With the libusb library the

libusb_get_device_list

function takes a list (parameter) however the list is a container for

libusb_device

, which is a opaque pointer. Is there a way to allocate a opaque pointer? Below is the function's mapping:

public fun libusb_get_device_list(ctx: kotlinx.cinterop.CValuesRef<cnames.structs.libusb_context>?, list: kotlinx.cinterop.CValuesRef<kotlinx.cinterop.CPointerVar<kotlinx.cinterop.CPointerVar<cnames.structs.libusb_device> /* = kotlinx.cinterop.CPointerVarOf<kotlinx.cinterop.CPointer<cnames.structs.libusb_device>> */> /* = kotlinx.cinterop.CPointerVarOf<kotlinx.cinterop.CPointer<kotlinx.cinterop.CPointerVarOf<kotlinx.cinterop.CPointer<cnames.structs.libusb_device>>>> */>?): platform.posix.ssize_t /* = kotlin.Long */ { /* compiled code */ }

Jonas Bark

08/28/2019, 3:00 PM

Does kotlin-native (iOS) has problems with dashes in pod dependencies? e.g.

cocoapods { ... pod("SignalR-ObjC") }

fails with

> Task :redacted:cinteropSignalR-ObjCIosX64 FAILED

Exception in thread "main" java.lang.Error: /var/folders/5w/vjnd8mf17jlclpg31lfzlk0h0000gn/T/tmp3333782877975402348.m:1:9: fatal error: module 'SignalR' not found

napperley

08/29/2019, 3:50 AM

When using a C library (via Kotlin Native) with Kotlin Coroutines would it be better to go with a synchronous API (eg http://libusb.sourceforge.net/api-1.0/group__libusb__syncio.html ), or a asynchronous API (eg http://libusb.sourceforge.net/api-1.0/group__libusb__asyncio.html )?

tateisu

08/29/2019, 4:06 AM

Is there .toKString() with charset specification? I'm using Mingw, strerror() charset is locale dependent and setlocale() don't allow UTF-8 codepage.

Glen

08/30/2019, 10:42 PM

Hello everyone. I need to use a static C library, written by a friend of mine. How do I include it in a Kotlin/Native project, using CInterop? And also, how do I use the library from there in an android client?

Arkadii Ivanov

08/31/2019, 2:11 AM

Just in case anyone stuck with Gradle task

linkDebugTestLinuxX64

failing with error message

e: Unable to compile C bridges

on Ubuntu: you have to install

libtinfo5

and perhaps

libtinfo-dev

packages. Wasted 1h on this problem 😞

👍 1

napperley

08/31/2019, 8:46 AM

Is there a straightforward way to convert

CArrayPointer<UByteVar>

to a String?

Akram

08/31/2019, 7:21 PM

hello everyone , i'm just starting with kotlin native and want to understand how kotlin native concurrency and memory model works, so i need some tutorials or blogs thanks in advance

molikuner

08/31/2019, 10:12 PM

Could anyone get wasm32 compiling with Kotlin 1.3.50 on Linux? Just getting a JVM crash on

linkDebugExecutableWasm32

. Kotlin 1.3.41 is working fine.

Tobi

09/02/2019, 6:29 AM

Hey folks, is there a way to interop with a cocoapods swift dependency from kotlin/native in a multiplatform project?

Vincent Chen

09/02/2019, 3:17 PM

Hi everyone, I want to generate .so file for Android, only androidNativeArm64 / 32, how to generate x86 / x86_64 for android? Can i use linux???

:yes: 1

ribesg

09/03/2019, 10:07 AM

Just updating from 1.3.41 to 1.3.50, something broke:

> Task :...:bugsnag:cinteropBugsnagIos
Exception in thread "main" java.lang.IllegalStateException: clang_parseTranslationUnit2 failed with CXError_ASTReadError;
sourceFile = /var/folders/6l/fxc2038542q1pfrjs6br35pw0000gn/T/tmp447253035168640890tmp5260654680929876680.m
arguments = -framework Bugsnag -fmodules -isystem /Users/me/.konan/dependencies/clang-llvm-6.0.1-darwin-macos/lib/clang/6.0.1/include -B/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin -fno-stack-protector -stdlib=libc++ -arch arm64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS12.4.sdk -miphoneos-version-min=9.0.0 -I/Users/me/IdeaProjects/.../bugsnag/Carthage/Build/iOS/Bugsnag.framework/Headers -fobjc-arc -include-pch /var/folders/6l/fxc2038542q1pfrjs6br35pw0000gn/T/tmp1938929871985065456.pch -Werror=implicit-function-declaration -ferror-limit=0
	at org.jetbrains.kotlin.native.interop.indexer.UtilsKt.parseTranslationUnit(Utils.kt:99)
	at org.jetbrains.kotlin.native.interop.indexer.MacroConstantsKt.expandMacros(MacroConstants.kt:66)
	at org.jetbrains.kotlin.native.interop.indexer.MacroConstantsKt.findMacros(MacroConstants.kt:34)
	at org.jetbrains.kotlin.native.interop.indexer.IndexerKt.indexDeclarations(Indexer.kt:999)
	at org.jetbrains.kotlin.native.interop.indexer.IndexerKt.buildNativeIndexImpl(Indexer.kt:952)
	at org.jetbrains.kotlin.native.interop.indexer.NativeIndexKt.buildNativeIndex(NativeIndex.kt:91)
	at org.jetbrains.kotlin.native.interop.gen.jvm.MainKt.processCLib(main.kt:222)
	at org.jetbrains.kotlin.native.interop.gen.jvm.MainKt.interop(main.kt:38)
	at org.jetbrains.kotlin.cli.utilities.InteropCompilerKt.invokeInterop(InteropCompiler.kt:69)
	at org.jetbrains.kotlin.cli.utilities.MainKt.main(main.kt:18)

Cyrille QUÉMIN

09/03/2019, 12:33 PM

hey there, I have 2 mpp modules A and B. B is using A as a dependency. I produced FAT frameworks from both of them, and include both framework in my iOS app. Everything is good so far. The problem is I have a type in module A Type1 which is used in module 2. But in my ios App if I try to use them together I have an incompatibility error where A.Type1 is said to be incompatible with B.Type1. Whereas they are supposed to be the exactly the same. How can I solve that?

Denis Shurygin

09/03/2019, 12:50 PM

NSBundle.localizedStringForKey

doesn't work properly in pair with

NSString.localizedStringWithFormat

. Looks like

NSString

losing some metadata during conversion into Kotlin

String

. Here is example on Kotlin:

import platform.Foundation.NSBundle
import platform.Foundation.NSString
import platform.Foundation.localizedStringWithFormat

class TestClass(private val bundle: NSBundle) {
    fun localizedStringWithFormat(string: String): String {
        return NSString.localizedStringWithFormat(
                this.bundle.localizedStringForKey(string, "", "Localizable"), 5)
    }
}

Here is the code in swift:

let testClass = TestClass(bundle: Bundle.main)
let testString = "screen_main_plural_string"
let nativeStr = Bundle.main.localizedString(forKey: testString, value: "", table: "Localizable") as NSString

NSLog("swift: %@", NSString.localizedStringWithFormat(nativeStr, 5))
NSLog("kotlin: %@", testClass.localizedStringWithFormat(string: testString))

Output logs: swift: Plural: 5 apples kotlin: %#@value@

Arkadii Ivanov

09/03/2019, 11:29 PM

FreezableAtomicReference was introduced in Kotlin 1.3.40 and according to its release notes (https://blog.jetbrains.com/kotlin/2019/06/kotlin-1-3-40-released/) it was considered as experimental. No changes were made since its initial implementation. What is the status of it? Are there any known issues? Thanks!

Cyrille QUÉMIN

09/04/2019, 9:55 AM

Hey guys, I am building iOS fat framework and everything seems to be working fine on my iOS app. However I have this warning in the build logs:

w: Interop library /pathToUser/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlinx/kotlinx-io-iosarm64/0.1.14/1ece4fc59ccddcacf23bb04589c7c0f39a94b787/kotlinx-io-cinterop-sockets can't be exported with -Xexport-library

. Will I experience runtime crashes ? what does it mean exactly for the framework produced ?

galex

09/04/2019, 1:00 PM

Hello, do Kotlin enums become real ObjC enums (which are objects after all) or are they like real enums (two values share the same memory instance?

galex

09/04/2019, 1:15 PM

And what about nullability in Kotlin, does it translate correctly when used in Swift through ObjC?

serebit

09/04/2019, 2:42 PM

The new plugin for debugging K/N in IntelliJ seems to be corrupting my multiplatform projects... If I have it installed and activated, it changes the type of my modules to KONAN_NATIVE, which the normal Kotlin plugin doesn't like, and thus refuses to load.

Vincent Chen

09/04/2019, 5:53 PM

Hi, in my Kotlin/native project

.....
var outputLength = cValuesOf(0)
......
val outputBA = outputData.readBytes(outputLength convert int)

How to Convert outputLength to Int Thanks

napperley

09/04/2019, 9:21 PM

Is there some consideration being made about including wrappers to cover some common C Macros, which are in the bundled C libraries (varies by target)?

Vincent Chen

09/05/2019, 3:57 AM

hi, I write enum in my commonMain at K/N project, then build .so for Android. Now how can I use this enum ?? thanks~

Justin

09/05/2019, 8:17 PM

Trying to get a list of devs/companies working with KMP going here - feel free to add to the list! https://twitter.com/justinmkaufman/status/1169650267135991808?s=21

Vincent Chen

09/06/2019, 8:21 AM

Hi, Is it possible to get context at androidNativeArm64 ??? Because I Must Build Library include .so for Android(can’t use androidMain) + .framework for iOS Ex: getPackageName…. I think it is no. Then some ways to do this? Thanks

Sam Schilling

09/06/2019, 4:38 PM

Has anyone else experienced issues with NSObjects not being deallocated properly? I have a function that is called in a loop which allocates an NSObject (NSProcessInfo) but it never gets deallocated My loop runs for 150 ms and during that time application memory usage typically rises by ~50 MB, and when profiling I see it is because there are thousands of NSProcessInfo objects that never get deallocated (each one is only 4 KB)

fun elapsedRealtime() = (NSProcessInfo().systemUptime * 1_000)

val startTime = elapsedRealtime()
var currentTime = startTime
while (currentTime - startTime < 150) {
    currentTime = elapsedRealTime()
}

I would think NSProcessInfo objects should automatically be deallocated each time

elapsedRealtime

completes since the reference count would be 0, but I am unsure how Kotlin’s GC interacts with Swift/Objective-C’s ARC If I change the loop to run for 25 seconds for example my memory usage shoots up nearly 500 MB. This is running on macOS 10.14.6

Title

Sam Schilling

09/06/2019, 4:38 PM

fun elapsedRealtime() = (NSProcessInfo().systemUptime * 1_000)

val startTime = elapsedRealtime()
var currentTime = startTime
while (currentTime - startTime < 150) {
    currentTime = elapsedRealTime()
}

I would think NSProcessInfo objects should automatically be deallocated each time

elapsedRealtime

FWIW, I was able to greatly decrease the memory footprint by surrounding the function in an autorelease pool, but it still seems to hold onto a bunch of the objects without releasing, just less than before

fun elapsedRealTime() = autoreleasepool { NSProcessInfo().systemUptime * 1_000 }

In this case I can run for 25 seconds and only increase memory by about 7 MB (as opposed to 500 MB previously), but still that 7 MB never goes away after the fact

olonho

09/06/2019, 5:35 PM

insert GC call

<https://github.com/JetBrains/kotlin-native/blob/8e0e346492436cc9c40d87f38926e841954d1d4e/runtime/src/main/kotlin/kotlin/native/internal/GC.kt#L30>

if you need to force collection, K/N uses delayed reference counter, so some memory may add up

Sam Schilling

09/06/2019, 6:22 PM

@olonho I have tried that and it does not free up any of the memory

I even tried calling

GC.start()

first since it says collect will not do anything if it is stopped

olonho

09/06/2019, 6:30 PM

How do you measure?

Sam Schilling

09/06/2019, 6:31 PM

Mac Activity Monitor

Shows the memory gradually go up to 500 MB as soon as my loop starts, and the program continues to execute afterwards but memory never goes down even after GC collect call

I am writing a framework that is used in Swift as well and using the Xcode profiler to view allocations I see that the

@autoreleasepool content

section is never cleared

@olonho Created a gist, maybe you can try to reproduce with it? https://gist.github.com/sschilli/5692c4582a85daec9a3ace186d8b431c

I just came across something interesting… if I call

GC.collect

after the loop body, memory usage grows very quickly, up to 500 MB:

while (currentTime - startTime < 25_000L) {
    currentTime = timer.elapsedRealtime()
}
GC.collect()

However if I call it inside the loop body, it grows much slower, up to only 8 MB by the time 25 seconds expires:

while (currentTime - startTime < 25_000L) {
    currentTime = timer.elapsedRealtime()
    GC.collect()
}

Can anyone explain this disparity?

@olonho I didn’t think GC.collect would be context dependent?

Seems to imply a memory leak

Either way though memory usage continues to grow unbounded despite GC.collect call, just because NSProcessInfo isn’t deallocated properly

olonho

09/07/2019, 8:08 AM

Please file an issue, but note, that macOS memory manager doesn’t guarantee, that even after freeing OS footprint reduces, so real marker if leak is evergrowing memory usage or seen in analysis by tools like valgrind

View count: 5