gistfile1.hrl

#include "erl_nif.h"

typedef struct {
	int calls;
} PrivData;

static int load(ErlNifEnv* env, void** priv_data) {
	PrivData* data = enif_alloc(env, sizeof(PrivData));
	if (data == NULL) return -1;
	data->calls = 0;
	*priv_data = data;
	return 0;
}

static int reload(ErlNifEnv* env, void** priv_data) {
	return 0;
}
static void unload(ErlNifEnv* env, void* priv_data) {
	enif_free(env, priv_data);
}

static ERL_NIF_TERM get(ErlNifEnv* env)
{
    PrivData* data = (PrivData*) enif_get_data(env);
	data->calls++;
	return enif_make_int(env, data->calls);
}

static ERL_NIF_TERM increase(ErlNifEnv* env, ERL_NIF_TERM a1) {
	int i;
	enif_get_int(env, a1, &i);
	PrivData* data = (PrivData*) enif_get_data(env);
	return enif_make_int(env, i);
}

static ErlNifFunc nif_funcs[] =
{
    {"increase", 1, increase},
	{"get", 0, get}
};

ERL_NIF_INIT(niftest,nif_funcs,load,reload,NULL,unload);


% Erlang code ---

-module(niftest).
-export([init/0, increase/1, get/0]).
init() -> erlang:load_nif("./niftest", 0).
increase(_A) -> "Not implemented".
get() -> "Not implemented".

% Output ---

1> c(niftest).
{ok,niftest}
2> niftest:init().
ok
3> niftest:increase(5).
31360452