This repository contains code for Ren-C. It was adapted from the Atronix code for R3-Alpha, which is documented in this video:
https://www.youtube.com/watch?v=fMeTqPyrNF4
The code was working in July 2019. But as the project focus shifted to the web, limited development resources mean that desktop-only features like FFI have no owners. Hence the code has atrophied, and is broken out from the maintained extensions into an archival repository.
There are no scheduled plans to invest in the code. But the design is overall relatively sound. Anyone wanting FFI interoperability in Ren-C should definitely start from this extension and information presented in the video.
Almost always, a more rigorous form of interoperability can be achieved by building C code as an extension linked to the interpreter core. This provides more robust interaction than using brittle FFI calls from a GC-based language with unmanaged pointers. (This is true of basically every language FFI.)
However, this means needing to have access to a compiler. If not using a compiler is desired, another simple way that frequently works for triggering "foreign" functionality is to use CALL to invoke a command-line program that can perform the needed action. It can then write any returned information to a file (or stdout).
https://forum.rebol.info/t/putting-aside-the-ffi-for-now/1537