doc/examples/wfcqueue/cds_wfcq_enqueue.c

   1 /*
   2  * Copyright (C) 2013  Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   3  *
   4  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
   5  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
   6  *
   7  * Permission is hereby granted to use or copy this program for any
   8  * purpose,  provided the above notices are retained on all copies.
   9  * Permission to modify the code and to distribute modified code is
  10  * granted, provided the above notices are retained, and a notice that
  11  * the code was modified is included with the above copyright notice.
  12  *
  13  * This example shows how to enqueue nodes into a wfcqueue.
  14  */
  15
  16 #include <stdio.h>
  17 #include <stdlib.h>
  18
  19 #include <urcu/wfcqueue.h>      /* Wait-free concurrent queue */
  20 #include <urcu/compiler.h>      /* For CAA_ARRAY_SIZE */
  21
  22 /*
  23  * Nodes populated into the queue.
  24  */
  25 struct mynode {
  26         int value;                      /* Node content */
  27         struct cds_wfcq_node node;      /* Chaining in queue */
  28 };
  29
  30 int main(int argc, char **argv)
  31 {
  32         int values[] = { -5, 42, 36, 24, };
  33         struct cds_wfcq_head myqueue_head;      /* Queue head */
  34         struct cds_wfcq_tail myqueue_tail;      /* Queue tail */
  35         unsigned int i;
  36         int ret = 0;
  37         struct cds_wfcq_node *qnode;
  38
  39         cds_wfcq_init(&myqueue_head, &myqueue_tail);
  40
  41         /*
  42          * Adding nodes to the linked-list. Safe against concurrent
  43          * RCU traversals, require mutual exclusion with list updates.
  44          */
  45         for (i = 0; i < CAA_ARRAY_SIZE(values); i++) {
  46                 struct mynode *node;
  47
  48                 node = malloc(sizeof(*node));
  49                 if (!node) {
  50                         ret = -1;
  51                         goto end;
  52                 }
  53
  54                 cds_wfcq_node_init(&node->node);
  55                 node->value = values[i];
  56                 cds_wfcq_enqueue(&myqueue_head, &myqueue_tail,
  57                                 &node->node);
  58         }
  59
  60         /*
  61          * Show the queue content, iterate in the same order nodes were
  62          * enqueued, from oldest to newest.
  63          */
  64         printf("myqueue content:");
  65         __cds_wfcq_for_each_blocking(&myqueue_head, &myqueue_tail, qnode) {
  66                 struct mynode *node =
  67                         caa_container_of(qnode, struct mynode, node);
  68                 printf(" %d", node->value);
  69         }
  70         printf("\n");
  71 end:
  72         return ret;
  73 }