Module Eio_utils.Lf_queue

A lock-free multi-producer, single-consumer, thread-safe queue without support for cancellation. This makes a good data structure for a scheduler's run queue.

type 'a t

A queue of items of type 'a.

exception Closed
val create : unit -> 'a t

create () is a new empty queue.

val push : 'a t -> 'a -> unit

push t x adds x to the tail of the queue. This can be used safely by multiple producer domains, in parallel with the other operations.

val push_head : 'a t -> 'a -> unit

push_head t x inserts x at the head of the queue. This can only be used by the consumer (if run in parallel with pop, the item might be skipped).

  • raises Closed

    if t is closed and empty.

val pop : 'a t -> 'a option

pop t removes the head item from t and returns it. Returns None if t is currently empty.

  • raises Closed

    if t has been closed and is empty.

val is_empty : 'a t -> bool

is_empty t is true if calling pop would return None.

  • raises Closed

    if t has been closed and is empty.

val close : 'a t -> unit

close t marks t as closed, preventing any further items from being pushed.