From: Ben Gras <ben@minix3.org>
Date: Wed, 25 Aug 2010 07:25:32 +0000 (+0000)
Subject: <stddef.h> - alternative definition of offsetof for gcc using builtin
X-Git-Tag: v3.1.8~50
X-Git-Url: http://zhaoyanbai.com/repos/Bv9ARM.ch11.html?a=commitdiff_plain;h=1d0e0e217d2f5e46875b7ff7033bab1839cf231d;p=minix.git

<stddef.h> - alternative definition of offsetof for gcc using builtin
---

diff --git a/include/stddef.h b/include/stddef.h
index bfd6e2cee..a053c9eb5 100644
--- a/include/stddef.h
+++ b/include/stddef.h
@@ -6,7 +6,11 @@
 #include <sys/null.h>
 
 /* The following is not portable, but the compiler accepts it. */
+#ifdef __GNUC__
+#define offsetof(type, ident)	__builtin_offsetof (type, ident)
+#else
 #define offsetof(type, ident)	((size_t) (unsigned long) &((type *)0)->ident)
+#endif
 
 #if _EM_PSIZE == _EM_WSIZE
 typedef int ptrdiff_t;		/* result of subtracting two pointers */