This is the mail archive of the
newlib@sourceware.org
mailing list for the newlib project.
Re: Last <sys/cdefs.h> change
- From: Sebastian Huber <sebastian dot huber at embedded-brains dot de>
- To: newlib at sourceware dot org
- Date: Thu, 23 May 2013 10:03:01 +0200
- Subject: Re: Last <sys/cdefs.h> change
- References: <519DC581 dot 20602 at embedded-brains dot de> <20130523074440 dot GA11512 at calimero dot vinschen dot de>
On 05/23/2013 09:44 AM, Corinna Vinschen wrote:
On May 23 09:30, Sebastian Huber wrote:
Hello,
what is the reason for the change:
[...]
There is already a test for C11 some lines above:
#elif defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
/* Do nothing. They are language keywords. */
#else
/* Not supported. Implement them using our versions. */
If you want C11 in GCC, you have to specify -std=c11 or -std=gnu11.
gcc >= 4.6 defines _Static_assert even without -std=C11.
See http://cygwin.com/ml/cygwin/2013-05/msg00310.html
In this message the problem occurs with "gcc -std=gnu99". Asking for a C11
feature with such a command line seems to be contradictory.
I would use this approach:
--- newlib/libc/include/sys/cdefs.h 2013-05-23 09:21:47.817952315 +0200
+++ cdefs.h 2013-05-23 10:01:28.014875569 +0200
@@ -261,15 +261,15 @@
#define _Thread_local __thread
#elif defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
/* Do nothing. They are language keywords. */
+#elif !defined(__STDC_VERSION__) && __GNUC_PREREQ__(4, 6)
+/* Do nothing. They are provided for free. */
#else
/* Not supported. Implement them using our versions. */
#define _Alignas(x) __aligned(x)
#define _Alignof(x) __alignof(x)
#define _Noreturn __dead2
#define _Thread_local __thread
-#if __GNUC_PREREQ__(4, 6) && !defined(__cplusplus)
-/* Do nothing: _Static_assert() works as per C11 */
-#elif defined(__COUNTER__)
+#ifdef __COUNTER__
#define _Static_assert(x, y) __Static_assert(x, __COUNTER__)
#define __Static_assert(x, y) ___Static_assert(x, y)
#define ___Static_assert(x, y) typedef char __assert_ ## y[(x) ? 1 : -1]
--
Sebastian Huber, embedded brains GmbH
Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone : +49 89 189 47 41-16
Fax : +49 89 189 47 41-09
E-Mail : sebastian.huber@embedded-brains.de
PGP : Public key available on request.
Diese Nachricht ist keine geschÃftliche Mitteilung im Sinne des EHUG.