enif_test.c

#include "erl_nif.h"
#include <stdio.h>

static int load(ErlNifEnv* env, void** priv, ERL_NIF_TERM load_info)
{
	int *priv_int = enif_alloc(sizeof(int));
	*priv = (void *)priv_int;
	enif_get_int(env, load_info, priv_int);
	printf("loaded %i %i\r\n", UNIQ, *priv_int);
	return 0;
}

static int upgrade(ErlNifEnv* env, void** priv, void** old_priv, ERL_NIF_TERM load_info)
{
	int *old_priv_int = *old_priv;
	int *priv_int = enif_alloc(sizeof(int));
	*priv = (void *)priv_int;
	enif_get_int(env, load_info, priv_int);
	printf("upgraded %i %i %i\r\n", UNIQ, *priv_int, *old_priv_int);
	return 0;
}

static void unload(ErlNifEnv* env, void* priv)
{
	int *priv_int = priv;
	printf("unloaded %i %i\r\n", UNIQ, *priv_int);
	return;
}

static ERL_NIF_TERM compile_uniq(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{
	return enif_make_int(env, UNIQ);
}

static ERL_NIF_TERM load_uniq(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{
	return enif_make_int(env, *((int *)enif_priv_data(env)));
}

static ErlNifFunc nif_funcs[] = {
	{"compile_uniq", 0, compile_uniq},
	{"load_uniq", 0, load_uniq}
};

ERL_NIF_INIT(enif_test_mod, nif_funcs, &load, NULL, &upgrade, &unload);

enif_test.erl

-module(enif_test).

-compile(export_all).

compile(I) ->
	os:cmd("gcc -c -Wall -Werror -fpic -DUNIQ=" ++ integer_to_list(I) ++ " enif_test.c"),
	os:cmd("gcc -shared -o enif_test.so enif_test.o").

eset(I) -> ets:insert(a, {a, I}).

test_reload() ->
	ets:new(a, [public, named_table]),
	compile(1),
	eset(2),
	{module, _} = code:load_file(enif_test_mod),
	check(1, enif_test_mod:compile_uniq(), "nif compiled as expected"),
	check(2, enif_test_mod:load_uniq(), "nif initialised as expected"),
	compile(3),
	check(1, enif_test_mod:compile_uniq(), "nif not unexpectedly reloaded"),
	{module, _} = code:load_file(enif_test_mod),
	check(3, enif_test_mod:compile_uniq(), "nif reloaded post compile properly"),
	init:stop().

test_reload_post_delete() ->
	ets:new(a, [public, named_table]),
	compile(1),
	eset(2),
	{module, _} = code:load_file(enif_test_mod),
	check(1, enif_test_mod:compile_uniq(), "nif compiled as expected"),
	check(2, enif_test_mod:load_uniq(), "nif initialised as expected"),
	compile(3),
	check(1, enif_test_mod:compile_uniq(), "nif not unexpectedly reloaded"),
	true = code:delete(enif_test_mod),
	{module, _} = code:load_file(enif_test_mod),
	check(3, enif_test_mod:compile_uniq(), "nif reloaded post compile properly"),
	init:stop().

test_reload_post_purge() ->
	ets:new(a, [public, named_table]),
	compile(1),
	eset(2),
	{module, _} = code:load_file(enif_test_mod),
	check(1, enif_test_mod:compile_uniq(), "nif compiled as expected"),
	check(2, enif_test_mod:load_uniq(), "nif initialised as expected"),
	compile(3),
	check(1, enif_test_mod:compile_uniq(), "nif not unexpectedly reloaded"),
	true = code:delete(enif_test_mod),
	io:format("delete finished~n"),
	true = code:soft_purge(enif_test_mod),
	io:format("soft_purge finished~n"),
	{module, _} = code:load_file(enif_test_mod),
	check(3, enif_test_mod:compile_uniq(), "nif reloaded post compile properly"),
	init:stop().

test_reload_post_reload_purge() ->
	ets:new(a, [public, named_table]),
	compile(1),
	eset(2),
	{module, _} = code:load_file(enif_test_mod),
	check(1, enif_test_mod:compile_uniq(), "nif compiled as expected"),
	check(2, enif_test_mod:load_uniq(), "nif initialised as expected"),
	eset(3),
	{module, _} = code:load_file(enif_test_mod),
	check(3, enif_test_mod:load_uniq(), "nif reinitialised as expected"),
	compile(4),
	check(1, enif_test_mod:compile_uniq(), "nif not unexpectedly reloaded"),
	true = code:soft_purge(enif_test_mod),
	true = code:delete(enif_test_mod),
	{module, _} = code:load_file(enif_test_mod),
	check(4, enif_test_mod:compile_uniq(), "nif reloaded post compile properly"),
	init:stop().

test_reload_post_reload_complete_purge() ->
	ets:new(a, [public, named_table]),
	compile(1),
	eset(2),
	{module, _} = code:load_file(enif_test_mod),
	check(1, enif_test_mod:compile_uniq(), "nif compiled as expected"),
	check(2, enif_test_mod:load_uniq(), "nif initialised as expected"),
	eset(3),
	{module, _} = code:load_file(enif_test_mod),
	check(3, enif_test_mod:load_uniq(), "nif reinitialised as expected"),
	compile(4),
	check(1, enif_test_mod:compile_uniq(), "nif not unexpectedly reloaded"),
	true = code:soft_purge(enif_test_mod),
	io:format("soft_purge finished~n"),
	true = code:delete(enif_test_mod),
	io:format("delete finished~n"),
	true = code:soft_purge(enif_test_mod),
	io:format("soft_purge finished~n"),
	{module, _} = code:load_file(enif_test_mod),
	check(4, enif_test_mod:compile_uniq(), "nif reloaded post compile properly"),
	init:stop().

check(N, N, M) ->
	io:format("  CORRECT: ~s~n", [M]);
check(_, _, M) ->
	io:format("INCORRECT: ~s~n", [M]).

enif_test_mod.erl

-module(enif_test_mod).

-compile([export_all]).

-on_load(init/0).

init() ->
	ok = erlang:load_nif("./enif_test", eget()).

eget() ->
	[{a, I}] = ets:lookup(a, a), I.

compile_uniq() -> erlang:error(no_nif).
load_uniq() -> erlang:error(no_nif).

output

$ erlc enif_test.erl && erlc enif_test_mod.erl && for I in test_reload{,_post_{delete,purge,reload_{purge,complete_purge}}}; do echo $I:; echo; erl -noshell -s enif_test $I; echo; done
test_reload:

loaded 1 2
  CORRECT: nif compiled as expected
  CORRECT: nif initialised as expected
  CORRECT: nif not unexpectedly reloaded
upgraded 1 2 2
INCORRECT: nif reloaded post compile properly
unloaded 1 2
unloaded 1 2

test_reload_post_delete:

loaded 1 2
  CORRECT: nif compiled as expected
  CORRECT: nif initialised as expected
  CORRECT: nif not unexpectedly reloaded
upgraded 1 2 2
INCORRECT: nif reloaded post compile properly
unloaded 1 2
unloaded 1 2

test_reload_post_purge:

loaded 1 2
  CORRECT: nif compiled as expected
  CORRECT: nif initialised as expected
  CORRECT: nif not unexpectedly reloaded
delete finished
unloaded 1 2
soft_purge finished
loaded 3 2
  CORRECT: nif reloaded post compile properly
unloaded 3 2

test_reload_post_reload_purge:

loaded 1 2
  CORRECT: nif compiled as expected
  CORRECT: nif initialised as expected
upgraded 1 3 2
  CORRECT: nif reinitialised as expected
  CORRECT: nif not unexpectedly reloaded
unloaded 1 2
upgraded 1 3 3
INCORRECT: nif reloaded post compile properly
unloaded 1 3
unloaded 1 3

test_reload_post_reload_complete_purge:

loaded 1 2
  CORRECT: nif compiled as expected
  CORRECT: nif initialised as expected
upgraded 1 3 2
  CORRECT: nif reinitialised as expected
  CORRECT: nif not unexpectedly reloaded
unloaded 1 2
soft_purge finished
delete finished
unloaded 1 3
soft_purge finished
loaded 4 3
  CORRECT: nif reloaded post compile properly
unloaded 4 3