1CK_RING_ENQUEUE_SPSC_... BSD Library Functions Manual CK_RING_ENQUEUE_SPSC_...
2

NAME

4     ck_ring_enqueue_spsc_size — enqueue pointer into bounded FIFO and return
5     size of buffer
6

LIBRARY

8     Concurrency Kit (libck, -lck)
9

SYNOPSIS

11     #include <ck_ring.h>
12
13     bool
14     ck_ring_enqueue_spsc_size(ck_ring_t *ring, ck_ring_buffer_t *buffer,
15         void *entry, unsigned int *size);
16

DESCRIPTION

18     The ck_ring_enqueue_spsc_size(3) function enqueues the pointer entry into
19     the bounded buffer pointed to by ring in FIFO fashion.  The buffer
20     pointed to by buffer must be unique to ring and point to an array of
21     ck_ring_buffer_t of sufficient length (according to the power-of-2 ele‐
22     ments in the buffer).  The decoupling of the ring from the buffer serves
23     to address use-cases involving multiple address spaces and DMA, among
24     others.  If you are on non-POSIX platforms or wish for strict compliance
25     with C, then it is recommended to pass a pointer of type void ** for
26     entry.  This function is safe to call without locking for up to one con‐
27     current invocation of ck_ring_dequeue_spsc(3).  This function provides
28     wait-free progress guarantees.
29

EXAMPLE

31           #include <ck_ring.h>
32
33           /* This ring was previously initialized with ck_ring_init. */
34           ck_ring_t ring;
35
36           /* The ring was initialized for 1023 elements. */
37           ck_ring_buffer_t buffer[1024];
38
39           void
40           enqueue(void)
41           {
42                   void *entry = some_object;
43                   unsigned int length;
44
45                   /* Attempt to enqueue pointer to some_object into buffer. */
46                   if (ck_ring_enqueue_spsc(&ring, &buffer, &entry, &length) == false) {
47                           /*
48                            * The buffer was full and the enqueue operation
49                            * has failed.
50                            */
51                           return;
52                   }
53
54                   /*
55                    * If buffer length was 100 items or more at the time entry was
56                    * enqueued, do something.
57                    */
58                   if (length > 100) {
59                           do_something;
60                   }
61
62                   return;
63           }
64

RETURN VALUES

66     The function returns true if the value of entry was successfully enqueued
67     into ring.  This function will return the number of items in ring with
68     respect to the linearization point (the point in item that entry is
69     enqueued).  The function will return false if the value of entry could
70     not be enqueued which only occurs if ring was full.
71

SEE ALSO

73     ck_ring_init(3), ck_ring_dequeue_spmc(3), ck_ring_trydequeue_spmc(3),
74     ck_ring_enqueue_spmc(3), ck_ring_enqueue_spmc_size(3),
75     ck_ring_dequeue_spsc(3), ck_ring_enqueue_spsc(3), ck_ring_capacity(3),
76     ck_ring_size(3)
77
78     Additional information available at http://concurrencykit.org/
79
80                                April 20, 2013
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