Overview

emacs-module-rs provides high-level Rust binding and tools to write Emacs’s dynamic modules. It is easy to use if you know either Rust or Emacs.

It currently supports:

• Stable Rust (latest stable recommended; 1.56 minimum).
• Emacs 25 or above, built with module support.
• macOS, Linux, Windows.

Setting up

• Make sure your Emacs was compiled with module support. Check that module-file-suffix is not nil, and the function module-load is defined.
  • On macOS, the recommended installation method is MacPorts (emacs-app and emacs-mac-app).
  • On Windows, install Emacs via MSYS2: pacman -S mingw-w64-x86_64-emacs. (Emacs officially supports MSVCRT, not UCRT.)
• Install the Rust toolchain with rustup.
  • On Windows, use the stable-gnu toolchain, with the gcc from mingw-w64-x86_64-toolchain. This ensures CRT linkages match.

Notes

• When the optional feature bindgen is enabled, the raw binding will be generated from emacs-module.h at build time. You will also need to install clang. (This is recommended only for troubleshooting.) For example, on Windows:

  # In Powershell
  scoop install llvm
  
  $env:LIBCLANG_PATH = "$(scoop prefix llvm)\bin"
  cargo build --all
  

Known Issues

There is a bug (see issue #1) with Emacs 26 on Linux that prevents it from loading any dynamic modules (even those written in C), if:

• Emacs is built without thread support.
• The OS is Ubuntu 16.04 (Xenial).