Go/Elixir NIF Experiment

README.md

Go/Elixir NIF Experiment

This was a quick little experiment to try to call Go code from Elixir. To try it out, simply run

$ go build -buildmode=c-shared -o nif-test.so
$ iex test.exs

This will put you into an IEx shell in which you can call Test.test/2 to add two integers together via a call to a Go function.

go.mod

module nif-test

go 1.21.5

test.c

#include <erl_nif.h>

extern ERL_NIF_TERM test_nif(ErlNifEnv *env, int argc, const ERL_NIF_TERM *argv);

static ErlNifFunc nif_funcs[] = {
	{"test", 2, test_nif},
};

ERL_NIF_INIT(Elixir.Test, nif_funcs, NULL, NULL, NULL, NULL)

test.exs

defmodule Test do
  @on_load :init

  def init() do
    :erlang.load_nif("./nif-test", 0)
  end

  def test(_, _) do
    raise "nif not loaded"
  end
end

test.go

package main

/*
#cgo CFLAGS: -I/usr/lib/erlang/usr/include
#include <erl_nif.h>

typedef const ERL_NIF_TERM const_ERL_NIF_TERM;
*/
import "C"
import "unsafe"

//export test_nif
func test_nif(env *C.ErlNifEnv, argc C.int, argv *C.const_ERL_NIF_TERM) C.ERL_NIF_TERM {
	args := unsafe.Slice(argv, argc)

	var a, b C.int
	C.enif_get_int(env, args[0], &a)
	C.enif_get_int(env, args[1], &b)

	return C.enif_make_int(env, a+b)
}

func main() {
}