FFI and other forbidden friendships

Informative guide. This Book page explains Beskid but does not define the standard. For normative requirements, use the Beskid Standard.

Caution

This chapter is informative. Enforceable rules live under the Platform specification.

FFI is where languages go to die. Beskid separates language interop law (language-meta) from host dispatch (execution ABI) so you know which spec page to argue about.

Start by choosing the boundary you need, then read the applicable profile before writing declarations or host glue. This chapter provides the route; Interop and ABI and host provide the authoritative contracts.

What you will find here

| Section | Topic | | --- | --- | | Interop overview | Domain map and profiles. | | FFI and extern | extern and contract imports. | | C ABI profile | Link-time and dynamic resolution. | | Rust ABI profile | Boundary stability (not “import any crate”). | | Export and callbacks | Hosting Beskid from native code. |

accTitle: Foreign interface selection
accDescr: Beskid extern declarations select either the user-facing C ABI profile or the runtime-only Rust ABI profile.
flowchart LR
  bd[Beskid code] --> extern[extern / import]
  extern --> cabi[C ABI profile]
  extern --> rabi[Rust ABI profile]
  cabi --> native[Native library]
  rabi --> shims[Runtime shims]

Text equivalent: Beskid code reaches native libraries through an extern declaration. User code uses the C ABI profile. The Rust ABI profile is limited to language-owned runtime shims.

Tip

Keep an interop boundary narrow and explicit. If a design mixes several foreign runtimes, split it into individual boundaries and validate each against its profile before composing them.

Next

22. So you want to contribute