+// SPDX-FileCopyrightText: 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+// SPDX-FileCopyrightText: 2011-2012 Lai Jiangshan <laijs@cn.fujitsu.com>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
#ifndef _URCU_WFCQUEUE_H
#define _URCU_WFCQUEUE_H
/*
- * urcu/wfcqueue.h
- *
* Userspace RCU library - Concurrent Queue with Wait-Free Enqueue/Blocking Dequeue
- *
- * Copyright 2010-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- * Copyright 2011-2012 - Lai Jiangshan <laijs@cn.fujitsu.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <pthread.h>
struct __cds_wfcq_head *_h;
struct cds_wfcq_head *h;
} __attribute__((__transparent_union__)) cds_wfcq_head_ptr_t;
+
+typedef union {
+ const struct __cds_wfcq_head *_h;
+ const struct cds_wfcq_head *h;
+} __attribute__((__transparent_union__)) cds_wfcq_head_const_ptr_t;
#if defined(__clang__)
#pragma clang diagnostic pop
#endif
{
return head;
}
+
+/*
+ * This static inline is only present for compatibility with C++. It is
+ * effect-less in C.
+ */
+static inline const struct __cds_wfcq_head *__cds_wfcq_head_const_cast(const struct __cds_wfcq_head *head)
+{
+ return head;
+}
+
+/*
+ * This static inline is only present for compatibility with C++. It is
+ * effect-less in C.
+ */
+static inline const struct cds_wfcq_head *cds_wfcq_head_const_cast(const struct cds_wfcq_head *head)
+{
+ return head;
+}
+
#else /* #ifndef __cplusplus */
/*
cds_wfcq_head_ptr_t ret = { .h = head };
return ret;
}
+
+/*
+ * This static inline is used by internally in the static inline
+ * implementation of the API.
+ */
+static inline cds_wfcq_head_const_ptr_t __cds_wfcq_head_const_cast(const struct __cds_wfcq_head *head)
+{
+ cds_wfcq_head_const_ptr_t ret = { ._h = head };
+ return ret;
+}
+
+/*
+ * This static inline is used by internally in the static inline
+ * implementation of the API.
+ */
+static inline cds_wfcq_head_const_ptr_t cds_wfcq_head_const_cast(const struct cds_wfcq_head *head)
+{
+ cds_wfcq_head_const_ptr_t ret = { .h = head };
+ return ret;
+}
+
#endif /* #else #ifndef __cplusplus */
struct cds_wfcq_tail {
*
* No memory barrier is issued. No mutual exclusion is required.
*/
-extern bool cds_wfcq_empty(cds_wfcq_head_ptr_t head,
- struct cds_wfcq_tail *tail);
+extern bool cds_wfcq_empty(cds_wfcq_head_const_ptr_t head,
+ const struct cds_wfcq_tail *tail);
/*
* cds_wfcq_dequeue_lock: take the dequeue mutual exclusion lock.
return ret;
}
+static inline cds_wfcq_head_const_ptr_t cds_wfcq_head_const_cast_cpp(const struct __cds_wfcq_head *head)
+{
+ cds_wfcq_head_const_ptr_t ret = { ._h = head };
+ return ret;
+}
+
+static inline cds_wfcq_head_const_ptr_t cds_wfcq_head_const_cast_cpp(const struct cds_wfcq_head *head)
+{
+ cds_wfcq_head_const_ptr_t ret = { .h = head };
+ return ret;
+}
+
template<typename T> static inline bool cds_wfcq_empty(T head,
- struct cds_wfcq_tail *tail)
+ const struct cds_wfcq_tail *tail)
{
- return cds_wfcq_empty(cds_wfcq_head_cast_cpp(head), tail);
+ return cds_wfcq_empty(cds_wfcq_head_const_cast_cpp(head), tail);
}
template<typename T> static inline bool cds_wfcq_enqueue(T head,