From: Jan Beulich <jbeulich@suse.com>
Date: Thu, 3 Jul 2014 14:37:22 +0000 (+0200)
Subject: mini-os: add BUILD_BUG_ON()
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=8c55dfd44938421b9d076293c31ba4f3bd298db1;p=people%2Fliuw%2Flibxenctrl-split%2Fmini-os.git

mini-os: add BUILD_BUG_ON()

Just copy over what the hypervisor currently uses (comments dropped due
to being of unknown origin; the implementation was done by me anyway).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Acked-by: Tim Deegan <tim@xen.org>
---

diff --git a/include/lib.h b/include/lib.h
index 670c14f..62836c7 100644
--- a/include/lib.h
+++ b/include/lib.h
@@ -54,6 +54,15 @@
 #include <xen/event_channel.h>
 #include "gntmap.h"
 
+#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
+#define BUILD_BUG_ON(cond) ({ _Static_assert(!(cond), "!(" #cond ")"); })
+#define BUILD_BUG_ON_ZERO(cond) \
+    sizeof(struct { _Static_assert(!(cond), "!(" #cond ")"); })
+#else
+#define BUILD_BUG_ON_ZERO(cond) sizeof(struct { int:-!!(cond); })
+#define BUILD_BUG_ON(cond) ((void)BUILD_BUG_ON_ZERO(cond))
+#endif
+
 #ifdef HAVE_LIBC
 #include <sys/queue.h>
 #include <stdio.h>