NAME¶
ck_ring_enqueue_spmc_size
—
enqueue pointer into bounded FIFO and return size of
buffer
LIBRARY¶
Concurrency Kit (libck, -lck)
SYNOPSIS¶
#include
<ck_ring.h>
bool
ck_ring_enqueue_spmc_size
(
ck_ring_t
*ring,
ck_ring_buffer_t
*buffer,
void
*entry,
unsigned
int *length);
DESCRIPTION¶
The
ck_ring_enqueue_spmc
(
3)
function enqueues the pointer
entry into the
bounded buffer pointed to by
ring in FIFO
fashion. The buffer pointed to by
buffer must
be unique to
ring and point to an array of
ck_ring_buffer_t of sufficient length (according to the power-of-2 elements in
the buffer). 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
entry. 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).
This function provides wait-free progress guarantees for one active
invocation.
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
enqueue(void)
{
void *entry = some_object;
unsigned int length;
/* Attempt to enqueue pointer to some_object into buffer. */
if (ck_ring_enqueue_spmc_size(&ring, &buffer, &entry, &length) == false) {
/*
* The buffer was full and the enqueue operation
* has failed.
*/
return;
}
/*
* If entry was the 101st or greater pointer in the buffer,
* do something.
*/
if (length > 100) {
do_something;
}
return;
}
RETURN VALUES¶
The function returns true if the value of
entry
was successfully enqueued into
ring. The
function will return false if the value of
entry could not be enqueued which only occurs
if
ring was full. The number of entries in
the buffer with respect to the point in time that
entry is enqueued is stored in the integer
pointed to by
length.
SEE ALSO¶
ck_ring_init(3),
ck_ring_dequeue_spmc(3),
ck_ring_trydequeue_spmc(3),
ck_ring_enqueue_spmc(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/