package eio

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A queue of fibers waiting for an event.

type 'a t
val create : unit -> 'a t
val wake_all : 'a t -> 'a -> unit

wake_all t calls (and removes) all the functions waiting on t. If t is shared between domains, the caller must hold the mutex while calling this.

val wake_one : 'a t -> 'a -> [ `Ok | `Queue_empty ]

wake_one t is like wake_all, but only calls (and removes) the first waiter in the queue. If t is shared between domains, the caller must hold the mutex while calling this.

val is_empty : 'a t -> bool

is_empty t checks whether there are any functions waiting on t. If t is shared between domains, the caller must hold the mutex while calling this, and the result is valid until the mutex is released.

val await : mutex:Mutex.t option -> 'a t -> Ctf.id -> 'a

await ~mutex t id suspends the current fiber and adds its continuation to t. When the waiter is woken, the fiber is resumed and returns the result. If t can be used from multiple domains:

  • mutex must be set to the mutex to use to unlock it.
  • mutex must be already held when calling this function, which will unlock it before blocking. When await returns, mutex will have been unlocked.
val await_internal : mutex:Mutex.t option -> 'a t -> Ctf.id -> Fiber_context.t -> (('a, exn) result -> unit) -> unit

await_internal ~mutex t id ctx enqueue is like await, but the caller has to suspend the fiber. This also allows wrapping the enqueue function. Calls enqueue (Error (Cancelled _)) if cancelled. Note: enqueue is called from the triggering domain, which is currently calling wake_one or wake_all and must therefore be holding mutex.

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