# Module Netmcore_queue

    module Netmcore_queue: sig .. end

Shared queues

    type ('e, 'h) squeue

Queues where the elements have type `'e` and the header has type `'h`

    type ('e, 'h) squeue_descr

The marshallble descriptor of queues

    exception Empty

Raised when the queue is empty and the operation cannot be done

    val create : Netmcore.res_id -> 'h -> ('e, 'h) squeue

`create pool h`: Creates an empty queue in the `pool`, with header `h`

    val push : 'e -> ('e, 'h) squeue -> unit

`push x q`: Pushes a copy of `x` to the end of the queue `q`

    val pop_p : ('e, 'h) squeue -> ('e -> 'a) -> 'a

`pop_p q f`: Takes the first element `x` from the queue, removes it there, and calls `f x`. During the execution of `f` the value `x` is pinned and cannot be garbage-collected.

Raises `Empty` if the queue is empty.

    val pop_c : ('e, 'h) squeue -> 'e

`pop_c q`: Takes the first element `x` from the queue, removes it there, and returns a copy of `x` in normal memory.

Raises `Empty` if the queue is empty.

    val top_p : ('e, 'h) squeue -> ('e -> 'a) -> 'a

`pop_p q f`: Takes the first element `x` of the queue, and calls `f x`, without removing `x` from the queue. During the execution of `f` the value `x` is pinned and cannot be garbage-collected.

Raises `Empty` if the queue is empty.

    val top_c : ('e, 'h) squeue -> 'e

`pop_p q f`: Takes the first element `x` of the queue, and calls `f x`, without removing `x` from the queue. Returns a copy of `x` in normal memory.

Raises `Empty` if the queue is empty.

    val clear : ('e, 'h) squeue -> unit

Removes all elements from the queue

    val is_empty : ('e, 'h) squeue -> bool

Tests whether the queue is empty

    val length : ('e, 'h) squeue -> int

Returns the number of elements in the queue (O(1))

    val iter : ('e -> unit) -> ('e, 'h) squeue -> unit

`iter f q`: Iterates over the elements of the queue and calls `f x` for each element `x`. The function considers the list of elements at the time of calling `iter` as the list to iterate over. The queue is not locked during the iteration, and hence elements can be popped from the queue and pushed to the queue in parallel. The iteration does not take these modifications into account, though.

The elements `x` are pinned during the execution of `f` and will not be garbage-collected, even if a parallel `pop` removes them from the queue.

    val fold : ('a -> 'e -> 'a) -> 'a -> ('e, 'h) squeue -> 'a

`fold f accu q`

    val header : ('e, 'h) squeue -> 'h

Returns the header

    val heap : ('a, 'b) squeue -> Obj.t Netmcore_heap.heap

Returns the underlying heap

    val descr_of_squeue : ('e, 'h) squeue -> ('e, 'h) squeue_descr

Returns the descriptor

    val squeue_of_descr : Netmcore.res_id ->
           ('e, 'h) squeue_descr -> ('e, 'h) squeue

Look up the queue for this descriptor