# Early Access Preview of Kotlin/Native #

## Introduction ##

 Kotlin/Native is a LLVM backend for the Kotlin compiler. It consists of a machine code generation facility using the LLVM toolchain
and a native runtime implementation.

 _Kotlin/Native_ is primarily designed to allow compilation for platforms where
virtual machines are not desirable or possible (such as iOS or embedded targets),
or where the developer needs to produce a reasonably-sized self-contained binary
that doesn't require an additional execution runtime.

## Supported platforms ##

The _Kotlin/Native_ compiler produces mostly portable (modulo pointer size and target
triplet) LLVM bitcode, and as such can easily support any platform, as long as there's an LLVM
code generator for the platform.
 However, as actualy producing native code requires a platform linker and some
basic runtime shipped along with the translator, we only support a subset of all possible
target platforms. Currently _Kotlin/Native_ is being shipped and tested with support for
the following platforms:

 * Mac OS X 10.11 and later (x86-64)
 * x86-64 Ubuntu Linux (14.04, 16.04 and later), other Linux flavours may work as well
 * Apple iOS (arm64), cross-compiled on MacOS X host (`-target iphone`)
 * Raspberry Pi, cross-compiled on Linux host (`-target raspberrypi`)


 Adding support for other target platforms shouldn't be too hard, if LLVM support
 is available.

 ## Compatibility and features ##

To run _Kotlin/Native_ JDK8 or later for the host platform has to be installed.

The language and library version supported by this EAP release mostly match Kotlin 1.1.
However, there are certain limitations, see section [Known Limitations](#limitations).

 Currently _Kotlin/Native_ uses reference counting based memory management scheme with a cycle
collection algorithm. Multiple threads could be used, but no objects shared 
between threads are allowed.

_Kotlin/Native_ provides efficient interoperability with libraries written in C, and supports
automatic generation of Kotlin bindings from a C header file.
See the samples coming with the distribution.

  ## Getting Started ##

 Download _Kotlin/Native_ distribution and unpack it. You can run command line compiler with

	bin/kotlinc <some_file>.kt <dir_with_kt_files> -o <executable>.kexe

  During the first run it will download all the external dependencies, such as LLVM.

To see the list of available flags, run `kotlinc -h`.

For documentation on C interoperability stubs see INTEROP.md.

 ## <a name="limitations"></a>Known limitations ##

 ### Performance ###

 *** DO NOT USE THIS PREVIEW RELEASE FOR ANY PERFORMANCE ANALYSIS ***

 This is purely a technology preview of _Kotlin/Native_ technology, and is not yet tuned
for benchmarking and competitive analysis of any kind.

### Standard Library ###

  The standard library in _Kotlin/Native_ is known to be incomplete and doesn't include
certain methods available in standard library of Kotlin.

### Coroutines ###

Coroutines are not yet supported with this release.

### Reflection ###

Full reflection and class object references are not implemented.
Notice that property delegation (including lazy properties) *does* work.

### Microsoft Windows support ###

Due to significant differences in exception handling models on MS Windows and
other LLVM targets, current _Kotlin/Native_ may not produce executables working on
MS Windows. This situation could be improved in upcoming releases.
