Aeva / msvc_racket_and_you

How to embed Racket CS in a C++ program on Windows with Visual Studio 2019

How to embed Racket CS into C++ programs on Windows with Visual Studio

Windows users attempting to embed Racket CS into a C or C++ program will find that it is currently impossible to do so by only following the documentation, at least as of September 19th, 2021.

There are two pitfalls you will run into:

1. Racket CS is not distributed with .lib files for the dlls, so symbol resolution at link time is not possible without generating your own. Delay loading is suggested as a possibility, but there is no provided functionality to assist in this, so you're on your own to write all of your mountain of GetProcAddress boilerplate.

2. The Windows distribution of Racket CS 8.2 ships with the Linux chezscheme.h, so it is impossible to end up with a working program anyway.

Racket CS is built with MinGW, and as one of the maintainers has assured me, it is simply just not worth their time to support embedding Racket with the platform's native toolchain.

So the solutions to the above problems are:

1. Generate your own .lib file, or write your own GetProcAddress boilerplate. God help your painful deteriorating RSI-addled wrists, but take comfort that a maintainer didn't have to update the build system.

2. This project has the correct version of chezscheme.h. Apparently the build system has at least been updated to provide the correct headers now, so if you wait a bit, the official distribution will eventually be fine maybe.

Generating your own .lib files

1. Create a file called libracketcs_d9hn5s.def (or similar, if your .dll is not named libracketcs_d9hn5s.dll) with each symbol you need on a separate line after EXPORTS, like so:

   EXPORTS
   racket_boot
   declare_modules
   

2. Run this command (adjust the file names to match your dll version) from a Visual Studio developer command prompt:

   lib /def:libracketcs_d9hn5s.def /out:libracketcs_d9hn5s.lib /machine:x64
   

3. Add your libracketcs_d9hn5s.lib to the project's "Additional Dependencies" field in the Linker -> Input settings.

4. (Optional) use the "Custom Build Step" project setting to automate step 2. Use the same command for the "Command Line" field, set Outputs to "libracketcs_d9hn5s.lib", and set "Execute Before" to Link. You will have to rebuild the project every time you update defs however.