Hello, I'm wonder how can I have something like Ja...

# kotlin-native

[Alexandre Brown]

Hello, I'm wonder how can I have something like Java JNI but for Kotlin?
How do I generate a c/c++ header from Kotlin code?
I have a JVM project (not multiplatform) where I would like to create a small Kotlin class to genenrate the c++ header then I will write C++ code to fulfill my needs.

Is that doable?

[hfhbd]

Biggest question is, why javah does not work with byte code. How do other jvm language generate headers?
But for Kotlin, I guess, ksp sounds doable, just filter the native classes and create the c code.
Do you have a C code generator lib in mind?

[Big Chungus]

I usually just write java interfaces and generate from that. Then use ij java to kt concerter to get rid of those

[Big Chungus]

Oh and you can implement native side in kotlin native too!

[Big Chungus]

https://github.com/mpetuska/fake-kamera/blob/master/jni/src/linuxX64Main/kotlin/jni.kt

[Alexandre Brown]

@Big Chungus When I said "I will write C++ code to fulfill my needs" It's essentially writing C++ code that will use a c++ library that is not available only in C++.
So would this scenario still be a candidate to use Kotlin Native?
I'm extremely new to KN

[Alexandre Brown]

@hfhbd I'm new to this so anything that works I'll use basically, dont have any C code generator lib in mind.

[Big Chungus]

Ah, no. Kotlin native does not support cpp interop at the moment. You can hack it via c bindings, but i wouldn't recommend it

[Alexandre Brown]

Ok then my best option would be to use a Java Class + JNI yes ? @Big Chungus

[Big Chungus]

That would be my recommendation

[Big Chungus]

Or alternatively use kotlin external declarations on jvm and write c headers yourself (they're really not that hard once you've seen some examples)

[Big Chungus]

https://github.com/mpetuska/fake-kamera/blob/master/app/src/jvmMain/kotlin/jni/FakeCam.kt

[Big Chungus]

I personally prefer the latter, but it is a bit more involved to get used to