X-Git-Url: https://git.liburcu.org/?a=blobdiff_plain;f=include%2Furcu%2Fcompiler.h;h=09953f2c2b96eeb5dfd27e04b43825a717d1e38c;hb=4b3a7ebd5597b5e241c39110eb426f7832066308;hp=2f32b38d6fb1850291ebd500f0a2fdca53f5c428;hpb=06326a94ac233064654c7100b6384b2833f7b898;p=urcu.git

diff --git a/include/urcu/compiler.h b/include/urcu/compiler.h
index 2f32b38..09953f2 100644
--- a/include/urcu/compiler.h
+++ b/include/urcu/compiler.h
@@ -74,6 +74,23 @@
 		(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))
 
@@ -123,4 +140,30 @@
 				+ __GNUC_PATCHLEVEL__)
 #endif
 
+#ifdef __cplusplus
+#define caa_unqual_scalar_typeof(x)					\
+	std::remove_cv<std::remove_reference<decltype(x)>::type>::type
+#else
+#define caa_scalar_type_to_expr(type)					\
+	unsigned type: (unsigned type)0,				\
+	signed type: (signed type)0
+
+/*
+ * Use C11 _Generic to express unqualified type from expression. This removes
+ * volatile qualifier from expression type.
+ */
+#define caa_unqual_scalar_typeof(x)					\
+	__typeof__(							\
+		_Generic((x),						\
+			char: (char)0,					\
+			caa_scalar_type_to_expr(char),			\
+			caa_scalar_type_to_expr(short),		\
+			caa_scalar_type_to_expr(int),			\
+			caa_scalar_type_to_expr(long),			\
+			caa_scalar_type_to_expr(long long),		\
+			default: (x)					\
+		)							\
+	)
+#endif
+
 #endif /* _URCU_COMPILER_H */