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 single consumer interface is
protected by
sc_lock.
The
buf_ring_free
() function is used to free
a buf_ring. The user is responsible 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 dequeueing elements from a buf_ring.
The
buf_ring_dequeue_sc
() function is a
single-consumer interface to dequeue 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 enqueued,
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.