(* Why ii is not different from 0 ? *)

let ii = ref 0;;

let foo () =
  for i=0 to 100000000 do
    incr ii
  done
;;

let bar () =
  for i=0 to 3 do
    match Unix.fork () with
    | 0 ->
        begin
          foo ();
          exit 0;
        end
    | -1 -> failwith "fork"
    | _ -> ()
  done;
  for i=0 to 3 do ignore (Unix.wait ()) done;
  print_endline (string_of_int !ii)
;;

bar ();;