Public headers: use SPDX identifiers

[urcu.git] / include / urcu / compiler.h

diff --git a/include/urcu/compiler.h b/include/urcu/compiler.h
index 4806ee338a99706ae5bb9eedb503fdc54e00c661..5b994076f47c913b28d636ae6e7262261befe103 100644 (file)
--- a/include/urcu/compiler.h
+++ b/include/urcu/compiler.h
@@ -1,26 +1,20 @@
+// SPDX-FileCopyrightText: 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
 #ifndef _URCU_COMPILER_H
 #define _URCU_COMPILER_H
 
 /*
- * compiler.h
- *
  * Compiler definitions.
- *
- * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
  */
 
 #include <stddef.h>    /* for offsetof */
 
+#if defined __cplusplus
+# include <type_traits>        /* for std::remove_cv */
+#endif
+
 #define caa_likely(x)  __builtin_expect(!!(x), 1)
 #define caa_unlikely(x)        __builtin_expect(!!(x), 0)
 
@@ -70,6 +64,23 @@
                (type *)((char *)__ptr - offsetof(type, member));       \
        })
 
+/*
+ * caa_container_of_check_null - Get the address of an object containing a field.
+ *
+ * @ptr: pointer to the field.
+ * @type: type of the object.
+ * @member: name of the field within the object.
+ *
+ * Return the address of the object containing the field. Return NULL if
+ * @ptr is NULL.
+ */
+#define caa_container_of_check_null(ptr, type, member)                 \
+       __extension__                                                   \
+       ({                                                              \
+               const __typeof__(((type *) NULL)->member) * __ptr = (ptr); \
+               (__ptr) ? (type *)((char *)__ptr - offsetof(type, member)) : NULL; \
+       })
+
 #define CAA_BUILD_BUG_ON_ZERO(cond) (sizeof(struct { int:-!!(cond); }))
 #define CAA_BUILD_BUG_ON(cond) ((void)CAA_BUILD_BUG_ON_ZERO(cond))
 
@@ -82,7 +93,7 @@
 #define __rcu
 
 #ifdef __cplusplus
-#define URCU_FORCE_CAST(type, arg)     (reinterpret_cast<type>(arg))
+#define URCU_FORCE_CAST(_type, arg)    (reinterpret_cast<std::remove_cv<_type>::type>(arg))
 #else
 #define URCU_FORCE_CAST(type, arg)     ((type) (arg))
 #endif
@@ -108,7 +119,12 @@
 
 #define CAA_ARRAY_SIZE(x)      (sizeof(x) / sizeof((x)[0]))
 
-#ifdef __GNUC__
+/*
+ * URCU_GCC_VERSION is used to blacklist specific GCC versions with known
+ * bugs, clang also defines these macros to an equivalent GCC version it
+ * claims to support, so exclude it.
+ */
+#if defined(__GNUC__) && !defined(__clang__)
 # define URCU_GCC_VERSION      (__GNUC__ * 10000 \
                                + __GNUC_MINOR__ * 100 \
                                + __GNUC_PATCHLEVEL__)