doc/examples: fix typo in list example
[urcu.git] / doc / examples / list / cds_list_for_each_rcu.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 do a RCU linked list traversal, safely
14 * against concurrent RCU updates. cds_list_for_each_rcu() iterates on
15 * struct cds_list_head, and thus, either caa_container_of() or
16 * cds_list_entry() are needed to access the container structure.
17 */
18
19 #include <stdio.h>
20
21 #include <urcu.h> /* Userspace RCU flavor */
22 #include <urcu/rculist.h> /* RCU list */
23 #include <urcu/compiler.h> /* For CAA_ARRAY_SIZE */
24
25 /*
26 * Nodes populated into the list.
27 */
28 struct mynode {
29 int value; /* Node content */
30 struct cds_list_head node; /* Linked-list chaining */
31 };
32
33 int main(int argc, char **argv)
34 {
35 int values[] = { -5, 42, 36, 24, };
36 CDS_LIST_HEAD(mylist); /* Defines an empty list head */
37 unsigned int i;
38 int ret = 0;
39 struct cds_list_head *pos;
40
41 /*
42 * Each thread need using RCU read-side need to be explicitly
43 * registered.
44 */
45 rcu_register_thread();
46
47 /*
48 * Adding nodes to the linked-list. Safe against concurrent
49 * RCU traversals, require mutual exclusion with list updates.
50 */
51 for (i = 0; i < CAA_ARRAY_SIZE(values); i++) {
52 struct mynode *node;
53
54 node = malloc(sizeof(*node));
55 if (!node) {
56 ret = -1;
57 goto end;
58 }
59 node->value = values[i];
60 cds_list_add_tail_rcu(&node->node, &mylist);
61 }
62
63 /*
64 * RCU-safe iteration on the list.
65 */
66 printf("mylist content:");
67
68 /*
69 * Surround the RCU read-side critical section with rcu_read_lock()
70 * and rcu_read_unlock().
71 */
72 rcu_read_lock();
73
74 /*
75 * This traversal can be performed concurrently with RCU
76 * updates.
77 */
78 cds_list_for_each_rcu(pos, &mylist) {
79 struct mynode *node = cds_list_entry(pos, struct mynode, node);
80
81 printf(" %d", node->value);
82 }
83
84 rcu_read_unlock();
85
86 printf("\n");
87 end:
88 rcu_unregister_thread();
89 return ret;
90 }
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