buf_ring_peek (9)

Leading comments

Copyright (c) 2009 Bitgravity Inc
Written by: Kip Macy <kmacy@FreeBSD.org>
All rights reserved.

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(The comments found at the beginning of the groff file "man9/buf_ring_peek.9freebsd".)

NAME

buf_ring buf_ring_alloc buf_ring_free buf_ring_enqueue buf_ring_dequeue_mc buf_ring_dequeue_sc buf_ring_count buf_ring_empty buf_ring_full buf_ring_peek - multi-producer, {single, multi}-consumer lock-less ring buffer

SYNOPSIS

In sys/param.h In sys/buf_ring.h Ft struct buf_ring * Fn buf_ring_alloc int count struct malloc_type *type int flags struct mtx *sc_lock Ft void Fn buf_ring_free struct buf_ring *br struct malloc_type *type Ft int Fn buf_ring_enqueue struct buf_ring *br void *buf Ft void * Fn buf_ring_dequeue_mc struct buf_ring *br Ft void * Fn buf_ring_dequeue_sc struct buf_ring *br Ft int Fn buf_ring_count struct buf_ring *br Ft int Fn buf_ring_empty struct buf_ring *br Ft int Fn buf_ring_full struct buf_ring *br Ft void * Fn buf_ring_peek struct buf_ring *br

DESCRIPTION

The ifconfig functions provide a lock-less multi-producer and lock-less multi-consumer as well as single-consumer ring buffer.

The Fn buf_ring_alloc function is used to allocate a buf_ring ring buffer with Fa count slots using malloc_type Fa type and memory flags Fa flags . The single consumer interface is protected by Fa sc_lock .

The Fn buf_ring_free function is used to free a buf_ring. The user is responsible for freeing any enqueued items.

The Fn buf_ring_enqueue function is used to enqueue a buffer to a buf_ring.

The Fn buf_ring_dequeue_mc function is a multi-consumer safe way of dequeueing elements from a buf_ring.

The Fn buf_ring_dequeue_sc function is a single-consumer interface to dequeue elements - requiring the user to serialize accesses with a lock.

The Fn buf_ring_count function returns the number of elements in a buf_ring.

The Fn buf_ring_empty function returns TRUE if the buf_ring is empty, FALSE otherwise.

The Fn buf_ring_full function returns TRUE if no more items can be enqueued, FALSE otherwise.

The Fn buf_ring_peek function returns a pointer to the last element in the buf_ring if the buf_ring is not empty, NULL otherwise.

RETURN VALUES

The Fn buf_ring_enqueue function return Er ENOBUFS if there are no available slots in the buf_ring.

HISTORY

These functions were introduced in Fx 8.0 .