A library binding a blocking native call (accept/recv/connect/...) needs it
emitted __collect_safe so the thread deactivates for the call and doesn't pin
the stop-the-world collector. foreign-fn / defcfn take an optional trailing
:blocking; the backend emits (foreign-procedure __collect_safe ...). Needed for
the ring-janet-adapter socket-server port. ffi-binding-test asserts a thread
parked in a :blocking call doesn't block (collect).
A jolt library can now bind its own native dependencies and expose a Clojure API
over them — no jolt built-in required. This is the foundation for moving the
http-client / db / adapter functionality out of the host and into real libraries.
- jolt.ffi/foreign-fn (sugar: defcfn) is a compiler special form: a compile-time
-typed C signature lowers to a real Chez foreign-procedure (analyzer :ffi-fn ->
backend foreign-procedure), so calls are typed and marshaled, not eval'd.
- host/chez/ffi.ss provides the rest under jolt.ffi: load-library, alloc/free,
read/write/sizeof, ptr<->string, null/null?. Loaded after the loader snapshot
so a library's (require '[jolt.ffi]) still loads the macro side.
- Types: int/uint/long/ulong/int64/uint64/size_t/ssize_t/iptr/uptr/double/float/
pointer/string/void/uint8/char.
Validated end to end: a pure-Clojure file binds libc (getpid/strlen/abs) and
libsqlite3 (open/prepare/step/column/finalize over out-param pointers) and runs a
query. Gate test test/chez/ffi-binding-test.ss (make ffi); selfhost holds.
