module Lwt_main : sig..end
Main loop and event queue
This module controls the ``main-loop'' of Lwt.
val run : 'a Lwt.t -> 'a
run p calls the Lwt scheduler repeatedly until p resolves, and returns the value of p if it is fulfilled. If p is rejected with an exception, that exception is raised.
Every native or bytecode program that uses Lwt should always use this function for evaluating a promise at the top level (such as its main function or main loop), otherwise promises that depend on I/O operations will not be resolved.
let main () = Lwt_io.write_line Lwt_io.stdout "hello world" let () = Lwt_main.run @@ main ()
Note that you should avoid using run inside threads
- The calling threads will not resume before run returns.
- Successive invocations of run are serialized: an invocation of run will not terminate before all subsequent invocations are terminated.
Note also that it is not safe to call run in a function registered with Pervasives.at_exit, use the Lwt_main.at_exit function of this module instead.
val yield : unit -> unit Lwt.t
yield () is a threads which suspends itself and then resumes as soon as possible and terminates.
val enter_iter_hooks : (unit -> unit) Lwt_sequence.t
Functions that are called before the main iteration.
val leave_iter_hooks : (unit -> unit) Lwt_sequence.t
Functions that are called after the main iteration.
val exit_hooks : (unit -> unit Lwt.t) Lwt_sequence.t
Sets of functions executed just before the program exit.
- each hook is called exactly one time
- exceptions raised by hooks are ignored
val at_exit : (unit -> unit Lwt.t) -> unit
at_exit hook adds hook at the left of exit_hooks