README.md

# DLLLoaderHelper

[![windows](https://github.com/cocoa-xu/dll_loader_helper/actions/workflows/windows.yml/badge.svg)](https://github.com/cocoa-xu/dll_loader_helper/actions/workflows/windows.yml)
[![Hex.pm](https://img.shields.io/hexpm/v/dll_loader_helper.svg?style=flat&color=blue)](https://hex.pm/packages/dll_loader_helper)

Add a directory to DLL search path for Windows. 

Say you are building a library, `:library_name`, which loads some 3rd party shared libraries from
`:code.priv_dir(:library_name)/lib`. It's quite easy to add rpath on *nix systems, but we don't really have rpath in Windows. 

Therefore, we have to use [`AddDllDirectory`](https://docs.microsoft.com/en-us/windows/win32/api/libloaderapi/nf-libloaderapi-adddlldirectory) to manually add the directory that contains these
.dll files to the search path.

## Usage

```elixir
:ok = 
  case :os.type do
    {:win32, _} -> DLLLoaderHelper.addDLLDirectory("#{:code.priv_dir(:library_name)}/lib")
    _ -> :ok
  end
```

Note that calling `DLLLoaderHelper.addDLLDirectory/1` on *nix systems will NOT have any effect, and `:ok` will be returned.

A complete Elixir example available in [example/elixir](example/elixir).

## Installation

If [available in Hex](https://hex.pm/docs/publish), the package can be installed
by adding `dll_loader_helper` to your list of dependencies in `mix.exs`:

```elixir
def deps do
  [
    {:dll_loader_helper, "~> 0.1"}
  ]
end
```

Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)
and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
be found at <https://hexdocs.pm/dll_loader_helper>.