Lwt_timeout
Cancelable timeouts.
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.
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.