DouKaku?

(*ocamlc unix.cma xxx.ml*)
open Unix;;
let tctrans descr status f1 f2 x =
  let default = Unix.tcgetattr descr in
  Unix.tcsetattr descr status (f1 default);
  let res = f2 x in
  Unix.tcsetattr descr status default;
  res;;

let timeout v sec itimer f =
  let t = ref v in
  let itimer_init () =
    ignore (setitimer itimer {it_interval=sec; it_value=sec});
    t := v in
  let itimer_bak = 
    setitimer itimer {it_interval=0.; it_value=0.} in
  let signal_bak = 
    Sys.signal Sys.sigalrm (Sys.Signal_handle (fun _ -> t := not v)) in
  let res = f itimer_init t  in
  let _ = setitimer itimer itimer_bak in 
  let _ = Sys.signal Sys.sigalrm signal_bak in
  res;;

let input_checker sec s =
  tctrans Unix.stdout Unix.TCSADRAIN 
  (fun t -> {t with Unix.c_echo = false; Unix.c_icanon = false})
  (fun () -> 
    timeout false sec Unix.ITIMER_REAL (fun init_itimer timeout ->
      let result = Buffer.create (String.length s) in
      Printf.printf "Input(%s) => %s<ENTER>\n" s s;
      for i = 1 to 3 do
        Printf.printf "   %d. result %!" i;
        let c = input_char Pervasives.stdin in
        let rec loop = function
        | '\n' -> 
            let str = Buffer.contents result in
            Printf.printf "\b\b\b\b\b\b\b%s => %s\n%!" str
              (if !timeout then "TIME OUT" else
               if str = s then "OK" else "NG");
            Buffer.clear result;
        |  c ->
            Buffer.add_char result c;
            loop (input_char Pervasives.stdin)
        in loop (init_itimer (); c)
      done
  )) ();;

(* input_checker 5. "ABCDE";; *)