Cleanup: enable signed/unsigned compare compiler warning
[urcu.git] / doc / examples / rculfqueue / cds_lfq_dequeue.c
CommitLineData
d4b71408
MD
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 dequeue nodes from a RCU lock-free queue.
14 * This queue requires using a RCU scheme.
15 */
16
17#include <stdio.h>
18#include <stdlib.h>
19
b9050d91 20#include <urcu/urcu-memb.h> /* RCU flavor */
d4b71408
MD
21#include <urcu/rculfqueue.h> /* RCU Lock-free queue */
22#include <urcu/compiler.h> /* For CAA_ARRAY_SIZE */
23
24/*
25 * Nodes populated into the queue.
26 */
27struct mynode {
28 int value; /* Node content */
29 struct cds_lfq_node_rcu node; /* Chaining in queue */
30 struct rcu_head rcu_head; /* For call_rcu() */
31};
32
33static
34void free_node(struct rcu_head *head)
35{
36 struct mynode *node =
37 caa_container_of(head, struct mynode, rcu_head);
38
39 free(node);
40}
41
42int main(int argc, char **argv)
43{
44 int values[] = { -5, 42, 36, 24, };
45 struct cds_lfq_queue_rcu myqueue; /* Queue */
46 unsigned int i;
47 int ret = 0;
48
49 /*
50 * Each thread need using RCU read-side need to be explicitly
51 * registered.
52 */
b9050d91 53 urcu_memb_register_thread();
d4b71408 54
b9050d91 55 cds_lfq_init_rcu(&myqueue, urcu_memb_call_rcu);
d4b71408
MD
56
57 /*
58 * Enqueue nodes.
59 */
60 for (i = 0; i < CAA_ARRAY_SIZE(values); i++) {
61 struct mynode *node;
62
63 node = malloc(sizeof(*node));
64 if (!node) {
65 ret = -1;
66 goto end;
67 }
68
69 cds_lfq_node_init_rcu(&node->node);
70 node->value = values[i];
71 /*
72 * Both enqueue and dequeue need to be called within RCU
73 * read-side critical section.
74 */
b9050d91 75 urcu_memb_read_lock();
d4b71408 76 cds_lfq_enqueue_rcu(&myqueue, &node->node);
b9050d91 77 urcu_memb_read_unlock();
d4b71408
MD
78 }
79
80 /*
81 * Dequeue each node from the queue. Those will be dequeued from
82 * the oldest (first enqueued) to the newest (last enqueued).
83 */
84 printf("dequeued content:");
85 for (;;) {
86 struct cds_lfq_node_rcu *qnode;
87 struct mynode *node;
88
89 /*
90 * Both enqueue and dequeue need to be called within RCU
91 * read-side critical section.
92 */
b9050d91 93 urcu_memb_read_lock();
d4b71408 94 qnode = cds_lfq_dequeue_rcu(&myqueue);
b9050d91 95 urcu_memb_read_unlock();
d4b71408
MD
96 if (!qnode) {
97 break; /* Queue is empty. */
98 }
99 /* Getting the container structure from the node */
100 node = caa_container_of(qnode, struct mynode, node);
101 printf(" %d", node->value);
b9050d91 102 urcu_memb_call_rcu(&node->rcu_head, free_node);
d4b71408
MD
103 }
104 printf("\n");
105 /*
106 * Release memory used by the queue.
107 */
108 ret = cds_lfq_destroy_rcu(&myqueue);
109 if (ret) {
110 printf("Error destroying queue (non-empty)\n");
111 }
112end:
b9050d91 113 urcu_memb_unregister_thread();
d4b71408
MD
114 return ret;
115}
This page took 0.034407 seconds and 4 git commands to generate.