CK_RING_DEQUEUE_SPMC(3) | Library Functions Manual | CK_RING_DEQUEUE_SPMC(3) |
NAME
ck_ring_dequeue_spmc
—
dequeue pointer from bounded FIFO
LIBRARY
Concurrency Kit (libck, -lck)
SYNOPSIS
#include
<ck_ring.h>
bool
ck_ring_dequeue_spmc
(ck_ring_t
*ring, ck_ring_buffer_t
*buffer, void
*result);
DESCRIPTION
The
ck_ring_dequeue_spmc
(3)
function dequeues a pointer from the bounded buffer pointed to by
ring in FIFO fashion. The pointer is stored in the
pointer pointed to by result. The buffer pointed to by
buffer must be unique to ring.
The decoupling of the ring from the buffer serves to address use-cases
involving multiple address spaces and DMA, among others. If you are on
non-POSIX platforms or wish for strict compliance with C, then it is
recommended to pass a pointer of type void ** for
result. This function is safe to call without locking
for UINT_MAX concurrent invocations of
ck_ring_dequeue_spmc
(3) or
ck_ring_trydequeue_spmc
(3)
and up to one concurrent
ck_ring_enqueue_spmc
(3)
or
ck_ring_tryenqueue_spmc
(3)
invocation. This function provides lock-free progress guarantees.
EXAMPLE
#include <ck_ring.h> /* This ring was previously initialized with ck_ring_init. */ ck_ring_t ring; /* The ring was initialized for 1023 elements. */ ck_ring_buffer_t buffer[1024]; void dequeue(void) { void *result; /* Dequeue from ring until it is empty. */ while (ck_ring_dequeue_spmc(&ring, &buffer, &result) == true) { /* * Results contains the oldest pointer in ring * since the dequeue operation returned true. */ operation(result); } /* An empty ring was encountered, leave. */ return; }
RETURN VALUES
The function returns true if the buffer was non-empty. The result of the dequeue operation is stored in the value pointed to by result. The function will return false if the buffer was empty and the value in result will be undefined.
SEE ALSO
ck_ring_init(3), ck_ring_trydequeue_spmc(3), ck_ring_enqueue_spmc(3), ck_ring_enqueue_spmc_size(3), ck_ring_dequeue_spsc(3), ck_ring_enqueue_spsc(3), ck_ring_enqueue_spsc_size(3), ck_ring_capacity(3), ck_ring_size(3)
Additional information available at http://concurrencykit.org/
April 20, 2013 |