Hello there everyone, I just wanted to ask that what is the best way to use the coroutines in application class. I found several examples but could not make sure are they safe codes and which one is best from performance perspective. Thank you

How do I use mutable states + jetpack compose to use a button to switch images?

*if you can't use remember in the applications class since you have to use remember in a @Composable function

I get this Type 'TypeVariable(T)' has no method 'getValue(Nothing?, KProperty<*>)' and thus it cannot serve as a delegate trying to follow https://dev.to/zachklipp/remember-mutablestateof-a-cheat-sheet-10ma

Tried to simplify it and now the app crashes.

Fixed it, my issue when I initially set the value during the var creation it wasn't the correct 'id' number since it was for xml vector images.

When will Jetpack Compose be availiable for iOS?

Does kotlin native currently not support hash codes changing throughout the lifecycle of a class for data classes? Details in 🧵

Hi all, i am hunting a memory leak and suspsect it might be related to

refTo

. I am passing a ByteArray reference by calling bytes.refTo to POSIX

read

and now wonder when the pinning will be undone? I see that the

CValuesRef

returned by

getPointer

takes an

AutofreeScope

. Where does that come from? And when is it cleared? I.e. what is the lifetime of a

CValuesRef

returned by

refTo

?

Hi all, I have multi module kmm project that support the following four targets • iOS • Android • JVM • JS Some of these modules depend on each other ex: Module A doesn’t have any dependencies Module B depend on Module A and a pod project for the iOS Module C depend on Module B Now, Module C will contains all the dependencies that Module B have along with the pod project. Is there is a way not to include all Module B dependencies inside module C?

Hi all, I have an error that I’m not sure if it is a bug or not. Whenever I have a module that import a pod file in it, during the running of

:linkDebugTestIosSimulatorArm64

I get the following error:

e: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld invocation reported errors
The /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld command returned non-zero exit code: 1.
output:
ld: warning: object file (/var/folders/sd/vq_ngt5j7kqfzb0t3z91t5g40000gn/T/konan_temp6320318283573195829/result.o) was built for newer iOS Simulator version (14.0) than being linked (9.0)

Undefined symbols for architecture arm64:
  "_OBJC_CLASS_$__TtC10ModuleAKMMFunctions", referenced from:
      objc-class-ref in result.o
ld: symbol(s) not found for architecture arm64

P.S Only one class have the annotation

@objc

(KMMFunctions) so that I can easily use the pod implementation without any hassles. The whole pod module is running with no issues alone and after importing it to xcode project. PodSpec is:

s.ios.deployment_target = '13.0'
s.osx.deployment_target  = '12.0'
s.tvos.deployment_target = '13.0'
s.watchos.deployment_target = '8.0'

cocoapods {
    this.summary = "Module Summary"
    this.version = rootProject.version.toString()
    this.authors = "Me"
    this.ios.deploymentTarget = "13.0"
    this.osx.deploymentTarget = "12.0"
    this.tvos.deploymentTarget = "13.0"
    this.watchos.deploymentTarget = "8.0"
    framework {
        this.baseName = currentModuleName
    }
    pod("LOCAL POD") {
        version = "1.0.0"
        source = path(project.file("../iOSLibs/POD FOLDER NAME"))
    }
}

Kotlin v1.7.21 IntelliJ IDEA Ultimate v2022.3

hi, is there online documentation for the platform.posix.* library?

Hi, I found that on Kotlin Native, the time-consuming of throwing and catching exceptions is about 5~10 times that of JVM. Is this problem known? Below is my test code, they run on the same device.

fun main(args: Array<String>) {
    throwTest()
}

var createExceptionTime: Duration = Duration.ZERO

@OptIn(ExperimentalTime::class)
fun throwTest() {
    repeat(20) {
        createExceptionTime = Duration.ZERO
        measureTime {
            repeat(100) {
                runCatching {
                    throwException(100)
                }
            }
        }.also {
            println("Throw Performance Test：totalTime=$it throwTime=${it - createExceptionTime} createErrorTime=$createExceptionTime")
        }
    }
}


@OptIn(ExperimentalTime::class)
fun throwException(deep: Int) {
    if (deep == 0) throw measureTimedValue { RuntimeException() }.apply { createExceptionTime += duration }.value
    throwException(deep - 1)
}

Logs on Jvm: Throw Performance Test：totalTime=6.928553ms throwTime=5.908972ms createErrorTime=1.019581ms Throw Performance Test：totalTime=1.357407ms throwTime=797.797us createErrorTime=559.61us Throw Performance Test：totalTime=1.215410ms throwTime=649.083us createErrorTime=566.327us Throw Performance Test：totalTime=1.023574ms throwTime=528.187us createErrorTime=495.387us Throw Performance Test：totalTime=973.957us throwTime=488.259us createErrorTime=485.698us Throw Performance Test：totalTime=943.841us throwTime=456.6us createErrorTime=487.241us Throw Performance Test：totalTime=940.144us throwTime=455.628us createErrorTime=484.516us Throw Performance Test：totalTime=954.059us throwTime=454.954us createErrorTime=499.105us Throw Performance Test：totalTime=954.739us throwTime=464.041us createErrorTime=490.698us Throw Performance Test：totalTime=953.431us throwTime=461.697us createErrorTime=491.734us Throw Performance Test：totalTime=946.232us throwTime=456.769us createErrorTime=489.463us Throw Performance Test：totalTime=962.239us throwTime=454.854us createErrorTime=507.385us Throw Performance Test：totalTime=957.696us throwTime=460.617us createErrorTime=497.079us Throw Performance Test：totalTime=956.284us throwTime=467.273us createErrorTime=489.011us Throw Performance Test：totalTime=954.624us throwTime=473.158us createErrorTime=481.466us Throw Performance Test：totalTime=952.835us throwTime=458.23us createErrorTime=494.605us Throw Performance Test：totalTime=936.177us throwTime=454.877us createErrorTime=481.3us Throw Performance Test：totalTime=936.955us throwTime=453.158us createErrorTime=483.797us Throw Performance Test：totalTime=952.953us throwTime=454.16us createErrorTime=498.793us Throw Performance Test：totalTime=932.074us throwTime=455.823us createErrorTime=476.251us Logs on Native:

Task :runReleaseExecutableNative

Throw Performance Test：totalTime=6.699028ms throwTime=6.183869ms createErrorTime=515.159us Throw Performance Test：totalTime=7.806001ms throwTime=7.431287ms createErrorTime=374.714us Throw Performance Test：totalTime=6.487319ms throwTime=6.302656ms createErrorTime=184.663us Throw Performance Test：totalTime=6.939379ms throwTime=6.678405ms createErrorTime=260.974us Throw Performance Test：totalTime=6.550303ms throwTime=6.358103ms createErrorTime=192.2us Throw Performance Test：totalTime=6.354265ms throwTime=6.186179ms createErrorTime=168.086us Throw Performance Test：totalTime=6.395004ms throwTime=6.207162ms createErrorTime=187.842us Throw Performance Test：totalTime=6.308159ms throwTime=6.150593ms createErrorTime=157.566us Throw Performance Test：totalTime=6.553794ms throwTime=6.305356ms createErrorTime=248.438us Throw Performance Test：totalTime=6.257863ms throwTime=6.143301ms createErrorTime=114.562us Throw Performance Test：totalTime=6.256012ms throwTime=6.142164ms createErrorTime=113.848us Throw Performance Test：totalTime=6.403581ms throwTime=6.276113ms createErrorTime=127.468us Throw Performance Test：totalTime=6.257133ms throwTime=6.143897ms createErrorTime=113.236us Throw Performance Test：totalTime=6.224807ms throwTime=6.125721ms createErrorTime=99.086us Throw Performance Test：totalTime=6.252487ms throwTime=6.156452ms createErrorTime=96.035us Throw Performance Test：totalTime=6.167458ms throwTime=6.074793ms createErrorTime=92.665us Throw Performance Test：totalTime=6.258211ms throwTime=6.110785ms createErrorTime=147.426us Throw Performance Test：totalTime=6.206690ms throwTime=6.109968ms createErrorTime=96.722us Throw Performance Test：totalTime=6.157968ms throwTime=6.066772ms createErrorTime=91.196us Throw Performance Test：totalTime=6.203606ms throwTime=6.106344ms createErrorTime=97.262us

Can someone help me out with this newbie question? https://stackoverflow.com/questions/74826174/pass-value-from-kotlin-native-to-c

Error: Suspension functions can be called only within coroutine body for the code doing a remove and after a logout:

suspend fun doLogout(token: String) {
    val userId = appService.currentUser?.id

        realm.write {

            var user = query<UserInfo>("_id = $0", userId).first().find()
            if (user != null) {
                val productIndex =
                    user.FCMToken.withIndex().findLast { it.value == token }!!.index

                user = findLatest(user)!!.also {
                    it.FCMToken.removeAt(productIndex)
                }
                copyToRealm(user)

                appService.currentUser?.logOut() // Suspension functions can be called only within coroutine body

            }
        }
}

Is there anyway to fix this without changing much code? I need to do first the db operation then logOut()

Why was the examples removed from the kotlin-native repo? I am not able to find any sort of interop examples on the new suggested link?

Kotlin/Native GC pause time up to 30 milliseconds Every Time，Is this GC time normal?

Did anybody create a Jvm from Kotlin/Native (C)? I get this error message:

Error occurred during initialization of VM
Failed setting boot class path.

and don't know, if I did make a mistake in Kotlin.

Hello 👋 I am trying to use a cocoapod in our multi module KM Project. I have all bindings showing up, but am two experiencing two seperate issues during compile time. 1. It seems as though the

assemble<ProjectName>RelaseXCFramework

does not automatically link the cocoapod frameworks into the build. for each architecture i have to manually specify the libraries cocoapod location using

linkerOpts("-F$frameworkPath")
                        linkerOpts("-rpath", frameworkPath)
                        linkerOpts("-framework", "<Library>"

Once i do this, i can get a successful build, but a failure once i utilize the framework in my project with the following errror

dyld[32068]: Library not loaded: <FrameworkClass>

I feel like I have an incorrect setting as no where in docs is it stated that i have to manually link cocoapod frameworks. Any suggestions?

I am writing Advanced Kotlin book, where I present advanced aspects of Kotlin development, and as a part of that, I decided to present specificity of different flavors, including Kotlin/Native. Since I do not feel strong enough in this topic, I am looking for a person with experience with Kotlin/Native, who would want to write a guest chapter about practical aspects of using it. It does not need to be long, as long as it offers value for those preparing to use Kotlin/Native, or trying to understand what makes this platform different.

How would I specify a relative path when linking a static library within

libraryPaths

?

headers = foo.h
staticLibraries = libfoo.a
libraryPaths = /some/relative/path

Hi everyone, I don't know if this is the correct channel. I'm working on a kmm project (Kotlin 1.7.0, kotlin.native.binary.memoryModel=experimental) and I have an IPWebSocket class.

class IPWebSocket() {//...
	private val requestQueue: MutableList<IPMessageRequest> = mutableListOf()
	//...

	fun send(request: IPMessageRequest) {
		requestQueue.add(request)
		webSocket.sendMessage(request)
		scope.launch {
            delay(REQUEST_TIMEOUT)
            requestQueue.firstOrNull { it == request }?.let {
                //Some operations
            }
        }
	}
	//...
	fun receive(msg: Message) {
		val iterator = requestQueue.listIterator()
        while (iterator.hasNext()) {
            val request = iterator.next()
            if (msg.msgid == request.msgid) {
                iterator.remove()
            }
        }
	}
}

With the new Native Memory Management, by reading the docs, I understood that I don't need to handle locks on the requestQueue like I was doing before with stately-iso-collection but I'm still getting ConcurrentModificationException on the send function. What I am doing wrong? Note: obviously the send and receive methods can be accessed by multiple threads EDIT: ok I think I found the problem, we're using kotlin.coroutines "1.6.0-native-mt" and -native-mt should be removed. But I think the app will slow down If I do that.

JNI again: How do you write this cpp code in Kotlin?

JNIEnv *env;
JNI_CreateJavaVM(&jvm, (void**)&env, &vm_args);

I tried this but always get the error, the env is null:

memScope {
  val env = alloc<JNIEnvVar>().ptr
  JNI_CreateJavaVM(jvm, env.reinterpret(), vmArgs.ptr)
  env.pointed.pointed!!.GetVersion!!(env) // GetVersion!! was null
}
`

So I guess there is an error with converting the env to

(void**)

https://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/invocation.html https://github.com/hfhbd/jniTest/blob/deferWorkaround/src/nativeMain/kotlin/Foo.kt

If I have a c function that takes a struct pointer and populates that reference with a value:

struct Foo foo;
init_too(&foo)
return foo

Is this the right way to perform the same task using cinterop?

val foo = Foo(NativePtr.NULL)
init_foo(foo.ptr)
return foo

Is there a way to get the name of a variable and print it out or store it as a string?

I need to pass a

ByteArray

buffer from Kotlin to C so that it can be written to. The underlying lib expects it in the form of an

iovec

. Do I have to have

StableRef

to do this?

iovec.iov_base

is expecting the buffer in the form of a

COpaquePointer

.

I started a VST3 virtual instrument plugin in Kotlin/native. Unfortunately, I'm facing major performance issues. The DAW's CPU usage indicator clearly shows my plugin uses way too much CPU. Even though some of my code could be optimised a bit (e.g. lookup tables instead of computing all waveforms ad hoc), I'm baffled at how much CPU the plugin is using while still a lot of the features haven't even been implemented yet. I suspect Kotlin/native's memory management might be the problem, because there are bursts of performance drops that might be caused by the GC. I tried to avoid creating unnecessary objects, even avoiding lambdas and iterators. I'm a bit at a loss what I could try next. Any suggestions? If you want to have a look at the source code, here's the Github project: https://github.com/digorydoo/kangaroo The core is in /src/nativeMain/kotlin/ch/digorydoo/kangaroo/audio/AudioProcessor.kt, onProcessBlock.

I'm confused on the difference between the following two pieces of code. For context, I need to pass a pointer to String to a C function and have that memory be valid after the current function call pops off the stack. To do that, the cinterop guide mentions allocating the c string in native memory using

val cstring = "some string".cstr.getPointer(nativeHeap)

This produces a pointer to valid memory. However, why does this function any differently than

val pinnedCstr = "some string".cstr.pin()

I want to manually unpin this value and avoid the copy if I can. This memory is no longer valid once it's accessed from the C library I'm interfacing with and I don't understand why

I have a more generalized question related to the above question. Since KMP is going to go stable soon, can we expect more robust documentation of cinterop? Right now things are very vague and pretty inconsistent. For example,

AutofreeScope

and

Arena

have absolutely no documentation. The examples of Kotlin and C String interop are inconsistent in their usage of

getPointer

or not. This leads to a lot of trial and error for people consuming non-trivial C libraries.