wfcqueue: document first/next return values

[urcu.git] / urcu / static / wfstack.h

diff --git a/urcu/static/wfstack.h b/urcu/static/wfstack.h
index 668ff7d6f101a963f5171d7a8714653cccd94526..018a1213b525d2266c6187da7b8fffd03dc94e43 100644 (file)
--- a/urcu/static/wfstack.h
+++ b/urcu/static/wfstack.h
@@ -6,10 +6,10 @@
  *
  * Userspace RCU library - Stack with with wait-free push, blocking traversal.
  *
- * TO BE INCLUDED ONLY IN LGPL-COMPATIBLE CODE. See wfstack.h for linking
- * dynamically with the userspace rcu library.
+ * TO BE INCLUDED ONLY IN LGPL-COMPATIBLE CODE. See urcu/wfstack.h for
+ * linking dynamically with the userspace rcu library.
  *
- * Copyright 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright 2010-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -47,9 +47,10 @@ extern "C" {
  * Stack implementing push, pop, pop_all operations, as well as iterator
  * on the stack head returned by pop_all.
  *
- * Wait-free operations: cds_wfs_push, __cds_wfs_pop_all.
- * Blocking operations: cds_wfs_pop, cds_wfs_pop_all, iteration on stack
- *                      head returned by pop_all.
+ * Wait-free operations: cds_wfs_push, __cds_wfs_pop_all, cds_wfs_empty,
+ *                       cds_wfs_first.
+ * Blocking operations: cds_wfs_pop, cds_wfs_pop_all, cds_wfs_next,
+ *                      iteration on stack head returned by pop_all.
  *
  * Synchronization table:
  *
@@ -283,7 +284,7 @@ _cds_wfs_pop_all_blocking(struct cds_wfs_stack *s)
 }
 
 /*
- * cds_wfs_first_blocking: get first node of a popped stack.
+ * cds_wfs_first: get first node of a popped stack.
  *
  * Content written into the node before enqueue is guaranteed to be
  * consistent, but no other memory ordering is ensured.
@@ -291,9 +292,11 @@ _cds_wfs_pop_all_blocking(struct cds_wfs_stack *s)
  * Used by for-like iteration macros in urcu/wfstack.h:
  * cds_wfs_for_each_blocking()
  * cds_wfs_for_each_blocking_safe()
+ *
+ * Returns NULL if popped stack is empty, top stack node otherwise.
  */
 static inline struct cds_wfs_node *
-_cds_wfs_first_blocking(struct cds_wfs_head *head)
+_cds_wfs_first(struct cds_wfs_head *head)
 {
        if (___cds_wfs_end(head))
                return NULL;
@@ -309,6 +312,9 @@ _cds_wfs_first_blocking(struct cds_wfs_head *head)
  * Used by for-like iteration macros in urcu/wfstack.h:
  * cds_wfs_for_each_blocking()
  * cds_wfs_for_each_blocking_safe()
+ *
+ * Returns NULL if reached end of popped stack, non-NULL next stack
+ * node otherwise.
  */
 static inline struct cds_wfs_node *
 _cds_wfs_next_blocking(struct cds_wfs_node *node)