CGO and FFI - Struct

libpoint.go

package main

/*
struct point {
	int x;
	int y;
};
*/
import "C"

// BEGIN C Compatibility
func (p C.struct_point) InGo() Point {
	return Point{
		X: int(p.x),
		Y: int(p.y),
	}
}

//export add
func add(cpoint C.struct_point) C.int {
	point := cpoint.InGo()
	return C.int(point.Add())
}

// END C Compatibility

// Point represents a point on a cartesian plane
type Point struct {
	X int
	Y int
}

// Add just adds X and Y
func (p Point) Add() int {
	return p.X + p.Y
}

// Apparently required for the compiler. Needs more reading
func main() {}

run.sh

#!/bin/bash

# npm install ffi

go build -o libpoint.so -buildmode=c-shared libpoint.go
node test.js

test.js

const ffi = require('ffi');
const Struct = require('ref-struct');

var Point = Struct({
	'x': 'int',
	'y': 'int',
})

const libpoint = ffi.Library('./libpoint', {
	'add': ['int', [Point]],
});

var p = new Point();
p.x = 5;
p.y = 20;

console.log(libpoint.add(p));