Warning: Reason support is experimental. We are looking for beta-tester and contributors.

Module Lwt_timeout

module Lwt_timeout : sig..end

Cancelable timeouts.

type t
val create : int -> (unit -> unit) -> t

Lwt_timeout.create n f creates a new timeout object with duration n seconds. f is the action, a function to be called once the timeout expires. f should not raise exceptions.

The timeout is not started until Lwt_timeout.start is called on it.

val start : t -> unit

Starts the given timeout.

Starting a timeout that has already been started has the same effect as stopping it, and then restarting it with its original duration. So, suppose you have timeout with a duration of three seconds, which was started two seconds ago. The next call to its action is scheduled for one second in the future. Calling Lwt_timeout.start timeout at this point cancels this upcoming action call, and schedules a call three seconds from now.

val stop : t -> unit

Stops (cancels) the given timeout.

val change : t -> int -> unit

Changes the duration of the given timeout.

If the timeout has already been started, it is stopped, and restarted with its new duration. This is similar to how Lwt_timeout.start works on a timeout that has already been started.

val set_exn_handler : (exn -> unit) -> unit

Lwt_timeout.set_exn_handler f sets the handler to be used for exceptions raised by timeout actions. Recall that actions are not allowed to raise exceptions. If they do raise an exception exn despite this, f exn is called.

The default behavior of f exn, set by Lwt_timeout on program startup, is to pass exn to !Lwt.async_exception_hook. The default behavior of that is to terminate the process.