doc/examples: add rculfqueue example

[urcu.git] / doc / examples / rculfqueue / cds_lfq_enqueue.c

diff --git a/doc/examples/rculfqueue/cds_lfq_enqueue.c b/doc/examples/rculfqueue/cds_lfq_enqueue.c
new file mode 100644 (file)
index 0000000..a8c6f86
--- /dev/null
+++ b/doc/examples/rculfqueue/cds_lfq_enqueue.c
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2013  Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
+ * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
+ *
+ * Permission is hereby granted to use or copy this program for any
+ * purpose,  provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is
+ * granted, provided the above notices are retained, and a notice that
+ * the code was modified is included with the above copyright notice.
+ *
+ * This example shows how to enqueue nodes into a RCU lock-free queue.
+ * This queue requires using a RCU scheme.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <urcu.h>              /* RCU flavor */
+#include <urcu/rculfqueue.h>   /* RCU Lock-free queue */
+#include <urcu/compiler.h>     /* For CAA_ARRAY_SIZE */
+
+/*
+ * Nodes populated into the queue.
+ */
+struct mynode {
+       int value;                      /* Node content */
+       struct cds_lfq_node_rcu node;   /* Chaining in queue */
+};
+
+int main(int argc, char **argv)
+{
+       int values[] = { -5, 42, 36, 24, };
+       struct cds_lfq_queue_rcu myqueue;       /* Queue */
+       unsigned int i;
+       int ret = 0;
+
+       /*
+        * Each thread need using RCU read-side need to be explicitly
+        * registered.
+        */
+       rcu_register_thread();
+
+       cds_lfq_init_rcu(&myqueue, call_rcu);
+
+       /*
+        * Enqueue nodes.
+        */
+       for (i = 0; i < CAA_ARRAY_SIZE(values); i++) {
+               struct mynode *node;
+
+               node = malloc(sizeof(*node));
+               if (!node) {
+                       ret = -1;
+                       goto end;
+               }
+
+               cds_lfq_node_init_rcu(&node->node);
+               node->value = values[i];
+               /*
+                * Both enqueue and dequeue need to be called within RCU
+                * read-side critical section.
+                */
+               rcu_read_lock();
+               cds_lfq_enqueue_rcu(&myqueue, &node->node);
+               rcu_read_unlock();
+       }
+
+end:
+       rcu_unregister_thread();
+       return ret;
+}