Elixir Zig Example for macos/linux in Docker

This example is started in an attempt to get zigler working for macos. This project provides a minimalist zig nif example, and a minimalist c nif example.

This repo is supposed to demonstrate a working zig NIF. Currently, the nif only works on Linux. This project demonstrates that by using a Docker container. When run through the docker container, the nifs load and work, but when they are run in macos, they do not.

To use this project as intended, you need to be on macos, with Docker, elixir and zig already installed.

The nifs

There are 2 nifs in this example project. A nif written in C I used to help make sure I understood how a nif should work, and a zig nif to show how a zig nif will work. The C nif is at ./src/lib/c_src and the zig nif is at ./src/lib/zig_src.

The nifs are compiled when elixir is compiled using the elixir_make package, and the Makefile at ./src/Makefile. The elixir_make package provides the needed environment variables to locate the erlang headers. The nifs will be compiled when the elixir source is compiled.

When run through docker, both the C and zig nifs compile and work, but when run in macos, the zig nif refuses to load with an error

Docker instructions

$> docker-compose build 
....
<docker build output>
...
$> docker-compose run --rm elixir-linux mix deps.get
$> docker-compose run --rm elixir-linux mix test
..

Finished in 0.08 seconds (0.00s async, 0.08s sync)
2 tests, 0 failures

The tests are in the `./src/tests/ directory, and demonstrate that the nifs load and perform as expected.

macosx instructions

To run on macos, just cd to the ./src directory, and

$> mix deps.get
$> mix test
...
08:23:11.239 [warn]  The on_load function for module Elixir.ZigNif returned:
{:error,
 {:load_failed,
  'Failed to load NIF library: \'dlopen(./priv/libElixir.ZigNif.so, 2): Symbol not found: __tlv_bootstrap\n  Referenced from: ./priv/libElixir.ZigNif.so (which was built for Mac OS X 11.6)\n  Expected in: ./priv/libElixir.ZigNif.so\n in ./priv/libElixir.ZigNif.so\''}}



  1) test add works (ZigNifTest)
     test/zig_nif_test.exs:4
     ** (UndefinedFunctionError) function ZigNif.add/2 is undefined (module ZigNif is not available)
     code: assert ZigNif.add(1, 2) == 3
     stacktrace:
       (zig_nif 0.1.0) ZigNif.add(1, 2)
       test/zig_nif_test.exs:5: (test)

.

Finished in 0.02 seconds (0.00s async, 0.02s sync)
2 tests, 1 failure

The test demonstrates that the c nif runs, but the zig nif doesn't load.