package lwt_eio

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module Token : sig ... end
val with_event_loop : ?debug:bool -> clock:_ Eio.Time.clock -> (Token.t -> 'a) -> 'a

with_event_loop ~clock fn starts an Lwt event loop running and then executes fn t. When that finishes, the event loop is stopped.

  • parameter debug

    If true (the default is false), block attempts to perform effects in Lwt context. Get_context is allowed, so traceln still works, but this will detect cases where Lwt code tries to call Eio code directly.

module Promise : sig ... end
val run_eio : (unit -> 'a) -> 'a Lwt.t

run_eio fn allows running Eio code from within a Lwt function.

It runs fn () in a new Eio fiber and returns a promise for the result. If the returned promise is cancelled, it will cancel the Eio fiber. The new fiber is attached to the Lwt event loop's switch and will also be cancelled if the function passed to with_event_loop returns.

val run_lwt : (unit -> 'a Lwt.t) -> 'a

run_lwt fn allows running Lwt code from within an Eio function.

It runs fn () to create a Lwt promise and then awaits it. If the Eio fiber is cancelled, the Lwt promise is cancelled too.

This can only be called from the domain running Lwt. For other domains, use run_lwt_in_main instead.

val run_lwt_in_main : (unit -> 'a Lwt.t) -> 'a

run_lwt_in_main fn schedules fn () to run in Lwt's domain and waits for the result.

It is similar to Lwt_preemptive.run_in_main, but allows other Eio fibers to run while it's waiting. It can be called from any Eio domain.

If the Eio fiber is cancelled, the Lwt promise is cancelled too.

val notify : unit -> unit

notify () causes Lwt_engine.iter to return, indicating that the event loop should run the hooks and resume yielded threads.

Ideally, you should call this when an Eio fiber wakes up a Lwt thread, e.g. by resolving a Lwt promise. In most cases however this isn't really needed, since Lwt_unix.yield is deprecated and Lwt.pause will call this automatically.