The Native Development Kit (NDK) is a toolset that allows you to use C and C++ code with HarmonyOS. As a subset of HarmonyOS SDK, it provides native APIs, compile scripts, and compile toolchain to help you implement key application features using C or C++. The NDK covers only some basic underlying capabilities of HarmonyOS, such as the C runtime libc, graphics library, window system, multimedia, compression library, and Node-API that bridges ArkTS/JS and C code. It does not provide complete capabilities of ArkTS/JS APIs.
You can use Node-API in the NDK to access, create, and operate JS objects, and use native dynamic libraries in JS objects.
Use Scenarios
The NDK can be helpful for the cases in which you need to:
Increase performance in compute-intensive cases, such as games or physical simulations.
Reuse existing C or C++ libraries.
Customize a library based on CPU features, for example, performing Neon acceleration.
You are not advised to use the NDK to develop the following:
C or C++ applications
Applications that can run on a wide variety of HarmonyOS devices
[h2]Preparatory Knowledge
Linux C programming knowledge
The kernel and libc base libraries are extended from standards such as POSIX. Mastering basic Linux C programming knowledge helps you better understand HarmonyOS NDK development.
CMake
CMake is the default build system of HarmonyOS. For details about how to use CMake, see CMake Tutorial.
Node addons
ArkTS uses Node-API as the cross-language invocation interface. Familiarity with basic Node Addon development patterns helps you better understand how Node-API is used in the NDK.
Clang/LLVM
Basic knowledge of the Clang or LLVM compiler helps you compile better native dynamic libraries.
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Node-API, formerly called NAPI, is a set of APIs provided for you to use C and C++ code with HarmonyOS ArkTS/JS. Node-API is an extension of Node-API in Node.js but is not fully compatible.
[h2]NDK Directory Structure
For details about how to obtain the NDK, see NDK development tool directory.
build directory: stores the predefined toolchain script file hmos.toolchain.cmake
During compilation, CMake locates the file through CMAKE_TOOLCHAIN_FILE and reads the default values in this file, such as the compiler architecture and C++ library link mode.
build-tools folder: contains the build tools provided by the NDK.
# Check the CMake version. cmake -version # The version information is displayed. cmake version 3.16.5 CMake suite maintained and supported by Kitware (kitware.com/cmake).
llvm folder: contains the compilers provided by the NDK.
Common NDK Modules
The following table describes the common modules of the NDK and their functionalities.
| Module | Description |
|---|---|
| C standard library | Provides C standard library APIs based on musl. |
| C++ standard library | Provides the C++ runtime APIs. |
| Log | Provides APIs for outputting HiLog logs to the system. |
| Node-API | Provides APIs for interaction between ArkTS/JS and C/C++. |
| FFRT | Provides a task-based concurrent programming framework. |
| libuv | Provides a third-party asynchronous I/O library. |
| zlib | Provides the zlib library for basic data compression and decompression. |
| Rawfile | Provides APIs for reading various packaged resources of an application. |
| XComponent | Provides surface and touchscreen event APIs for you to develop high-performance graphics applications. |
| Drawing | Provides a 2D graphics library for drawing on the surface. |
| OpenGL | Provides OpenGL 3D graphics interfaces. |
| OpenSL ES | Provides APIs for 2D and 3D audio acceleration. |