a WIP ffi library for owl lisp

DEPENDENCIES

• libffi
• owl lisp compiled from source (new enough to have FP_API - tested with *owl-version* 0.2.3a)
• a local C compiler

USAGE

(import
 (owl toplevel)
 (prefix (ffi) ffi/))

(λ (_)
  (define-values (c-puts c-open c-write c-close)
    (ffi/funcs (ffi/open-library "libc.so")
      ("puts" ffi/void ffi/pointer)                         ;; void puts(char*)
      ("open" ffi/int32 ffi/pointer ffi/int32)              ;; int open(char*, int)
      ("write" ffi/uint32 ffi/int32 ffi/pointer ffi/uint32) ;; uint write(int, void*, uint)
      ("close" ffi/int32 ffi/int32)))                       ;; int close(int)

  (c-puts "Hello, World!")
  (let ((fd (c-open "/dev/stdout" 2))
        (s "Hello, World from write(2)!\n"))
    (c-write fd s (string-length s))
    (c-close fd)))

then compile with

$ ol -x c -o file.c file.scm
$ cc -I/path/to/owl/source/c -DPRIM_FP_API -DPRIM_CUSTOM test.c ffi.c -lffi -ldl -o test

FILES

• ffi.c - the module code that gets injected into the vm that interacts with libffi and libdl
• ffi.scm - a user-friendly lisp front-end to ffi.c

CAVEATS

• probably won't run under owl-winrt because of the dlopen and dlsym calls (might get ported some day)

this might be transformed into a extension if it turns out that they will stay in owl for good.