A Gradle plugin for Kotlin Multiplatform projects that generates binding code for common module access to native libraries. Supports Kotlin/Native using the built-in cinterop system and Kotlin/JVM using Jextract.
KJna currently supports the following Kotlin platforms:
- JVM
- Linux x86_64
- Linux ARM64
- Windows x86_64
See the releases page for a list of available versions.
Warning
This library is experimental. Some features such as nested pointers are untested and/or not implemented.
- Add the Maven Central repository to your dependency resolution configuration
repositories {
mavenCentral()
}
- Add the KJna Gradle plugin
plugins {
id("dev.toastbits.kjna").version("<version>")
}
- Add the KJna runtime dependency
dependencies {
implementation("dev.toastbits.kjna:runtime:<version>")
}
Jextract relies on Java 22's foreign memory API, so consumers of this library must be compiled using JDK 22 or greater (or JDK 21 with preview features enabled).
To use JDK 22
kotlin {
jvmToolchain(22)
}
To use JDK 21 with preview features
tasks.withType<JavaCompile>() {
options.compilerArgs.add("--enable-preview")
}
kotlin {
jvmToolchain(21)
}
Due to a KMP limitation, Java source files generated by Jextract are stored in /<project>/src/jvmMain/java/kjna (by default). You might want to exclude this directory from source control.
All other generated files are stored in /<project>/build/kjna.
Unless specified by the user, Jextract is downloaded automatically and stored in /<root-project>/build/jextract.
See the sample project for a working example using mpv.
kotlin {
jvm() // 'withJava()' is called automatically by KJna
val native_targets: List<KotlinNativeTarget> =
listOf(
linuxX64(),
...
)
kjna {
generate {
packages(native_targets) {
add("kjna.libmpv") {
// Disabled packages will have no function implementations
// Use the 'isAvailable()' companion method to check at runtime
enabled = true
addHeader(
"mpv/client.h", // Header path
"MpvClient" // Generated class name (gen.libmpv.LibMpv in this case)
)
libraries = listOf("mpv")
}
...
}
}
}
}