Native library

Learn to write native libraries with Kotlin/Native.

Native library output

Kotlin/Native produces not only executables but also native libraries. These libraries can be called from other languages.

In Gradle you write binaries { framework { ... } } or binaries { sharedLib() } inside a target block. On iOS a framework is produced; this framework is added to an Xcode project and called from Swift. On Linux/Windows a sharedLib (.so, .dll) is produced; it can be called from C or Python. This is how Kotlin code joins an existing platform ecosystem.

A NativeLib example

In this lesson we model library loading with a NativeLib class. In a real setup the Gradle binaries block produces this automatically.

Example: class NativeLib(val name: String) { fun load(): String = "loaded: $name" }. The call NativeLib("sqlite").load() returns "loaded: sqlite". A real library would call C functions at this point; here we report a successful load with a string. This simple model is enough to understand the library lifecycle.

Exercise Write NativeLib

Define class NativeLib(val name: String). Method fun load(): String should return "loaded: $name". In main, build val lib = NativeLib("sqlite") and write println(lib.load()).

Show example solution

class NativeLib(val name: String) {
    fun load(): String = "loaded: $name"
}
fun main() {
    val lib = NativeLib("sqlite")
    println(lib.load())
}

Test yourself

Complete the load method

class NativeLib(val name: String) {
    fun ____(): String = "loaded: $name"
}

Show answer

class NativeLib(val name: String) {
    fun load(): String = "loaded: $name"
}

Which output is produced on an iOS target?
- A framework
- A .dll file
- A .so file
- A .jar file
Show answer

A framework — The iOS target produces a framework; it is added to Xcode.
Match library parts

framework

iOS output
sharedLib

Linux/Windows output
binaries

Gradle block
Xcode

Apple IDE

Next lesson: Summary - Kotlin/Native

We Are Enhancing Your Experience

Cookie Preferences

Strictly Necessary Cookies

Analytical Cookies