X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=urcu%2Fcompiler.h;h=378f0eae8a59b3d0c1029566a174b0b6011e3009;hb=20da51e457e3e6a70141ccb40c911d44815f7f63;hp=074e70026a056cab15d1b05b7537ac333c2daedf;hpb=b52a3dc23521f7a21fb5ab3d2b53dad89c586ee4;p=userspace-rcu.git

diff --git a/urcu/compiler.h b/urcu/compiler.h
index 074e700..378f0ea 100644
--- a/urcu/compiler.h
+++ b/urcu/compiler.h
@@ -64,6 +64,7 @@
  * @member: name of the field within the object.
  */
 #define caa_container_of(ptr, type, member)				\
+	__extension__							\
 	({								\
 		const __typeof__(((type *) NULL)->member) * __ptr = (ptr); \
 		(type *)((char *)__ptr - offsetof(type, member));	\
@@ -89,12 +90,11 @@
 #define caa_is_signed_type(type)	((type) -1 < (type) 0)
 
 /*
- * Sign-extend to long if needed, and output type is unsigned long.
+ * Cast to unsigned long, sign-extending if @v is signed.
+ * Note: casting to a larger type or to same type size keeps the sign of
+ * the expression being cast (see C99 6.3.1.3).
  */
-#define caa_cast_long_keep_sign(v)		\
-	(caa_is_signed_type(__typeof__(v)) ?	\
-		(unsigned long) (long) (v) :	\
-		(unsigned long) (v))
+#define caa_cast_long_keep_sign(v)	((unsigned long) (v))
 
 /*
  * Don't allow compiling with buggy compiler.