Author: ed
Date: Wed Dec 14 09:09:37 2011
New Revision: 228495
URL: http://svn.freebsd.org/changeset/base/228495
Log:
Slightly alter the C1X definitions in in cdefs.h:
- Add _Alignas(). Unfortunately this macro is only partially functional.
The C1X standard will allow both an integer and a type name to be
passed to this macro, while this macro only allows an integer. To be
portable, one must use _Alignas(_Alignof(double)) to use type names.
- Don't do _Static_assert() when __COUNTER__ is not supported. We'd
better keep this implementation robust and allow it to be used in
header files, without mysteriously breaking older compilers.
Modified:
head/sys/sys/cdefs.h
Modified: head/sys/sys/cdefs.h
==============================================================================
--- head/sys/sys/cdefs.h Wed Dec 14 08:52:27 2011 (r228494)
+++ head/sys/sys/cdefs.h Wed Dec 14 09:09:37 2011 (r228495)
@@ -222,6 +222,7 @@
* Keywords added in C1X.
*/
#if defined(__cplusplus) && __cplusplus >= 201103L
+#define _Alignas(e) alignas(e)
#define _Alignof(e) alignof(e)
#define _Noreturn [[noreturn]]
#define _Static_assert(e, s) static_assert(e, s)
@@ -231,21 +232,23 @@
#else
/* Not supported. Implement them manually. */
#ifdef __GNUC__
+#define _Alignas(e) __attribute__((__aligned__(e)))
#define _Alignof(e) __alignof__(e)
#define _Noreturn __attribute__((__noreturn__))
#define _Thread_local __thread
#else
+#define _Alignas(e)
#define _Alignof(e) __offsetof(struct { char __a; e __b; },
__b)
#define _Noreturn
#define _Thread_local
#endif
#ifdef __COUNTER__
#define _Static_assert(e, s) __Static_assert(e, __COUNTER__)
-#else
-#define _Static_assert(e, s) __Static_assert(e, __LINE__)
-#endif
#define __Static_assert(e, c) ___Static_assert(e, c)
#define ___Static_assert(e, c) typedef char __assert ## c[(e) ? 1 : -1]
+#else
+#define _Static_assert(e, s)
+#endif
#endif
#if __GNUC_PREREQ__(2, 96)
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