Inbound & Outbound FFI
Foreign Function Interfaces (FFI) are a core mechanism for enabling integration of new languages into existing codebases or building on existing libraries. That said, the term “FFI” is often overloaded in ways that may be unclear or ambiguous, and the area can seem overwhelming to approach. In this post, I explain the two “directions” of FFI, some patterns for how FFI in each direction is handled in Rust and further break down some FFI design approaches.