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BUF_RING(9)		 BSD Kernel Developer's	Manual		   BUF_RING(9)

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
     #include <sys/param.h>
     #include <sys/buf_ring.h>

     struct buf_ring *
     buf_ring_alloc(int	count, struct malloc_type *type, int flags,
	 struct	mtx *sc_lock);

     void
     buf_ring_free(struct buf_ring *br,	struct malloc_type *type);

     int
     buf_ring_enqueue(struct buf_ring *br, void	*buf);

     void *
     buf_ring_dequeue_mc(struct	buf_ring *br);

     void *
     buf_ring_dequeue_sc(struct	buf_ring *br);

     int
     buf_ring_count(struct buf_ring *br);

     int
     buf_ring_empty(struct buf_ring *br);

     int
     buf_ring_full(struct buf_ring *br);

     void *
     buf_ring_peek(struct buf_ring *br);

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

     The buf_ring_alloc() function is used to allocate a buf_ring ring buffer
     with count	slots using malloc_type	type and memory	flags flags.  The sin-
     gle consumer interface is protected by sc_lock.

     The buf_ring_free() function is used to free a buf_ring.  The user	is re-
     sponsible for freeing any enqueued	items.

     The buf_ring_enqueue() function is	used to	enqueue	a buffer to a
     buf_ring.

     The buf_ring_dequeue_mc() function	is a multi-consumer safe way of	de-
     queueing elements from a buf_ring.

     The buf_ring_dequeue_sc() function	is a single-consumer interface to de-
     queue elements - requiring	the user to serialize accesses with a lock.

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

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

     The buf_ring_full() function returns TRUE if no more items	can be en-
     queued, FALSE otherwise.

     The 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 buf_ring_enqueue() function return ENOBUFS if there are no available
     slots in the buf_ring.

HISTORY
     These functions were introduced in	FreeBSD	8.0.

BSD			      September	27, 2012			   BSD

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | HISTORY

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