New module 'alignof'.

3 files changed, 67 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 3f6d793843..68b3f8ed25 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2009-05-08  Bruno Haible  <bruno@clisp.org>
+
+	New module 'alignof'.
+	* lib/alignof.h: New file.
+	* modules/alignof: New file.
+
 2009-05-04  David Bartley  <dtbartle@csclub.uwaterloo.ca>
             Bruno Haible  <bruno@clisp.org>
 
diff --git a/lib/alignof.h b/lib/alignof.h
new file mode 100644
index 0000000000..49e7757a0e
--- /dev/null
+++ b/lib/alignof.h
@@ -0,0 +1,41 @@
+/* Determine alignment of types.
+   Copyright (C) 2003-2004, 2006, 2009 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#ifndef _ALIGNOF_H
+#define _ALIGNOF_H
+
+#include <stddef.h>
+
+/* Determine the alignment of a type at compile time.  */
+#if defined __GNUC__
+# define alignof __alignof__
+#elif defined __cplusplus
+  template <class type> struct alignof_helper { char __slot1; type __slot2; };
+# define alignof(type) offsetof (alignof_helper<type>, __slot2)
+#elif defined __hpux
+  /* Work around a HP-UX 10.20 cc bug with enums constants defined as offsetof
+     values.  */
+# define alignof(type) (sizeof (type) <= 4 ? 4 : 8)
+#elif defined _AIX
+  /* Work around an AIX 3.2.5 xlc bug with enums constants defined as offsetof
+     values.  */
+# define alignof(type) (sizeof (type) <= 4 ? 4 : 8)
+#else
+# define alignof(type) offsetof (struct { char __slot1; type __slot2; }, __slot2)
+#endif
+
+#endif /* _ALIGNOF_H */
diff --git a/modules/alignof b/modules/alignof
new file mode 100644
index 0000000000..3635baabfe
--- /dev/null
+++ b/modules/alignof
@@ -0,0 +1,20 @@
+Description:
+Determine alignment of types.
+
+Files:
+lib/alignof.h
+
+Depends-on:
+
+configure.ac:
+
+Makefile.am:
+
+Include:
+"alignof.h"
+
+License:
+LGPLv2+
+
+Maintainer:
+Bruno Haible