NAME

       ck_ring_dequeue_spsc — dequeue pointer from bounded FIFO

LIBRARY

       Concurrency Kit (libck, -lck)

SYNOPSIS

       #include <ck_ring.h>

       bool
       ck_ring_dequeue_spsc(ck_ring_t *ring, ck_ring_buffer_t *buffer, void *result);

DESCRIPTION

       The  ck_ring_dequeue_spsc(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 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 result.   This
       function  is safe to call without locking for one concurrent invocation of ck_ring_dequeue_spsc(3) and up
       to  one  concurrent  ck_ring_enqueue_spsc(3)  invocation.  This  function  provides  wait-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_spsc(&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_spmc(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                          CK_RING_DEQUEUE_SPSC(3)