Getting Started

Prerequisites

Before you begin, make sure you have:

HarmonyOS (API 12+) device or emulator
DevEco Studio with HarmonyOS SDK
A .so shared library (pre-built or compiled from source)

Architecture support:

Architecture	ABI	Notes
ARM64	`arm64-v8a`	Default, verified
x86_64	`x86_64`	Add `x86_64` to `abiFilters`
RISC-V 64	`riscv64`	External toolchain; DevEco Studio does not support RISC-V build natively

Install arkffi

ohpm install arkffi

Import and use

import { dlopen, FFIType, CString, CFunction, JSCallback } from 'arkffi';

const lib = dlopen('libmylib.so', {
  calculate: {
    args: [FFIType.int32, FFIType.double, FFIType.CString],
    returns: FFIType.double,
  },
});

lib.symbols.calculate(42, 3.14, 'hello');
lib.close();

Use the raw bridge

For lower-level control, use the NAPI functions directly:

import ffi from 'liblibrary.so';

const handle = ffi.load('libffi_target.so');
ffi.defineFunction(handle, 'add', 'dd', 'd');
const sum = ffi.callBySig(handle, 'add', [2.0, 3.0], []);
ffi.close(handle);

Work with C pointers

const ptr = ffi.getSymbolPtr(handle, 'add');

ffi.callPtr(ptr, 'dd', 'd', [2.0, 3.0], []);

const cstr = new CString(ptr);
cstr.toString();
cstr.length;

Create callbacks

const cb = new JSCallback(
  (a: number, b: number): number => a + b,
  { args: [FFIType.int32, FFIType.int32], returns: FFIType.int32 },
);

cb.call(2, 3);   // → 5
cb.ptr;          // → slot handle or trampoline address
cb.close();

Getting Started

API Reference

Guides

Examples

Getting Started