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authorPaul Eggert <eggert@cs.ucla.edu>2015-02-05 15:52:20 -0800
committerPaul Eggert <eggert@cs.ucla.edu>2015-02-07 14:43:27 -0800
commit3999d26ead93990b244ada078073fb58fb8bb5be (patch)
treefb49ba47c9d88204c23135ef44ac4adf7919120e
parentf96ec27aa9f8fe871973b898ee407fe17681b6a7 (diff)
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Add ersatz _Static_assert on older C hosts
* misc/sys/cdefs.h (_Static_assert): Define a substitute, if on a
pre-C11 C platform that is not known to support _Static_assert.
-rw-r--r--ChangeLog6
-rw-r--r--assert/assert.h1
-rw-r--r--misc/sys/cdefs.h8
3 files changed, 14 insertions, 1 deletions
diff --git a/ChangeLog b/ChangeLog
index ade23843ac..4584975f3e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2015-02-07  Paul Eggert  <eggert@cs.ucla.edu>
+
+	Add ersatz _Static_assert on older C hosts
+	* misc/sys/cdefs.h (_Static_assert): Define a substitute, if on a
+	pre-C11 C platform that is not known to support _Static_assert.
+
 2015-02-07  Richard Braun  <rbraun@sceen.net>
 
 	* hurd/hurd/signal.h (_hurd_critical_section_lock): Don't unlock
diff --git a/assert/assert.h b/assert/assert.h
index ae777931c5..d04c58cc8a 100644
--- a/assert/assert.h
+++ b/assert/assert.h
@@ -113,7 +113,6 @@ __END_DECLS
 
 
 #if defined __USE_ISOC11 && !defined __cplusplus
-/* Static assertion.  Requires support in the compiler.  */
 # undef static_assert
 # define static_assert _Static_assert
 #endif
diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
index 09ee352e1f..99e94cce86 100644
--- a/misc/sys/cdefs.h
+++ b/misc/sys/cdefs.h
@@ -399,6 +399,14 @@
 # endif
 #endif
 
+#if (!defined _Static_assert && !defined __cplusplus \
+     && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \
+     && (!__GNUC_PREREQ (4, 6) || defined __STRICT_ANSI__))
+# define _Static_assert(expr, diagnostic) \
+    extern int (*__Static_assert_function (void)) \
+      [!!sizeof (struct { int __error_if_negative: (expr) ? 2 : -1; })]
+#endif
+
 #include <bits/wordsize.h>
 
 #if defined __LONG_DOUBLE_MATH_OPTIONAL && defined __NO_LONG_DOUBLE_MATH