Hi,

I am trying to find the most simple and, if possible, clean way to synchronize my threads.

In this particular case, semaphores would be ideal
(alternatively, unbounded channels)

  (* Create a new semaphore with a given initial value. *)
  val create : int -> t

  (* V *)
  val up : t -> unit

  (* P *)
  val down : t -> unit

  val try_down : t -> bool

The "down" or "try_down" are almost the solutions, but not quite.

"down" may block forever ---> there is no timeout at all
                              (I need some)

"try_down" --->  the timeout is zero
                 (I prefer a non-zero timeout)

Obviously, I could use "try_down" in a loop, checking the system time myself and then either give up or actually manage to decrement the semaphore.

Is there a better solution than this?

(There is a Unix module, there are signals, but I am not sure whether it is safe to use them in multithreaded program.
 At least, I did not have a luck.)

Thanks in advance for patience &| help.