This is part 3 of my tutorial for using the Racket FFI. You can find part 1 here and part 2 here.

In this post, we will experiment with some low-level operations with pointers, union types, and custom C types. The main takeaway will be the custom C types, which let you define abstractions that hide the details of the C representation when manipulating data in Racket.

This is part 2 of my tutorial on using the Racket FFI. If you haven’t read part 1 yet, you can find it here. Update: part 3 is also now available here.

Part 2 will continue with more Cairo examples. In this installment, I plan to go over some more advanced FFI hacking such as handling computed argument values, custom return arguments, and using C structs.

Update: this post is now part of a series. Part 2 is here and part 3 is here.

I’ve seen several people ask for a tutorial on Racket’s foreign function interface (FFI), which allows you to dynamically load C libraries for use in Racket code. While I think the documentation for the FFI is quite good, it is a lot of information to process and the overview examples may be tricky to run for a beginner.

With that in mind, this blog post will provide a step-by-step tutorial for Racket’s FFI that requires minimal setup. All that you will need to follow along is a copy of Racket and ideally a DrRacket window.