Kotlin/Native libraries

Kotlin compiler specifics

To produce a library with the Kotlin/Native compiler use the -produce library or -p library flag. For example:

$ kotlinc-native foo.kt -p library -o bar 

This command will produce a bar.klib with the compiled contents of foo.kt.

To link to a library use the -library <name> or -l <name> flag. For example:

$ kotlinc-native qux.kt -l bar 

This command will produce a program.kexe out of qux.kt and bar.klib

cinterop tool specifics

The cinterop tool produces .klib wrappers for native libraries as its main output. For example, using the simple libgit2.def native library definition file provided in your Kotlin/Native distribution

$ cinterop -def samples/gitchurn/src/nativeInterop/cinterop/libgit2.def -compiler-option -I/usr/local/include -o libgit2 

we will obtain libgit2.klib.

See more details in C Interop

klib utility

The klib library management utility allows you to inspect and install the libraries.

The following commands are available:

• content – list library contents:

  $ klib contents <name> 

• info – inspect the bookkeeping details of the library

  $ klib info <name> 

• install – install the library to the default location use

  $ klib install <name> 

• remove – remove the library from the default repository use

  $ klib remove <name> 

All of the above commands accept an additional -repository <directory> argument for specifying a repository different to the default one.

$ klib <command> <name> -repository <directory> 

Several examples

First let's create a library. Place the tiny library source code into kotlinizer.kt:

package kotlinizer val String.kotlinized get() = "Kotlin $this" 

$ kotlinc-native kotlinizer.kt -p library -o kotlinizer 

The library has been created in the current directory:

$ ls kotlinizer.klib kotlinizer.klib 

Now let's check out the contents of the library:

$ klib contents kotlinizer 

You can install kotlinizer to the default repository:

$ klib install kotlinizer 

Remove any traces of it from the current directory:

$ rm kotlinizer.klib 

Create a very short program and place it into a use.kt:

import kotlinizer.* fun main(args: Array<String>) { println("Hello, ${"world".kotlinized}!") } 

Now compile the program linking with the library you have just created:

$ kotlinc-native use.kt -l kotlinizer -o kohello 

And run the program:

$ ./kohello.kexe Hello, Kotlin world! 

Have fun!

Advanced topics

 - foo/ - $component_name/ - ir/ - Serialized Kotlin IR. - targets/ - $platform/ - kotlin/ - Kotlin compiled to LLVM bitcode. - native/ - Bitcode files of additional native objects. - $another_platform/ - There can be several platform specific kotlin and native pairs. - linkdata/ - A set of ProtoBuf files with serialized linkage metadata. - resources/ - General resources such as images. (Not used yet). - manifest - A file in the java property format describing the library.