These are the slides and the example code I used in my FFI lighting talk. Broadly the examples assume a POSIX operating system and the S.M.A.R.T. example assumes Linux but could be ported elsewhere easy enough. Be careful, the examples are arranged to fit on a projector screen more than correctness:)

Simple hello world example

Example passing params to C function

Example using pointers and semi-realistic computation

libc example that gets the current process id

Native code returns pointers to structs containing hard drive diagnostic information (Linux specific)

showoff slides