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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 16:11:47 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 16:11:47 +0000
commit758f820bcc0f68aeebac1717e537ca13a320b909 (patch)
tree48111ece75cf4f98316848b37a7e26356e00669e /lib/alignof.h
parentInitial commit. (diff)
downloadcoreutils-758f820bcc0f68aeebac1717e537ca13a320b909.tar.xz
coreutils-758f820bcc0f68aeebac1717e537ca13a320b909.zip
Adding upstream version 9.1.upstream/9.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+/* Determine alignment of types.
+ Copyright (C) 2003-2004, 2006, 2009-2022 Free Software Foundation, Inc.
+
+ This file is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Lesser General Public License as
+ published by the Free Software Foundation; either version 2.1 of the
+ License, or (at your option) any later version.
+
+ This file 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 Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
+
+#ifndef _ALIGNOF_H
+#define _ALIGNOF_H
+
+#include <stddef.h>
+
+/* alignof_slot (TYPE)
+ Determine the alignment of a structure slot (field) of a given type,
+ at compile time. Note that the result depends on the ABI.
+ This is the same as alignof (TYPE) and _Alignof (TYPE), defined in
+ <stdalign.h> if __alignof_is_defined is 1.
+ Note: The result cannot be used as a value for an 'enum' constant,
+ due to bugs in HP-UX 10.20 cc and AIX 3.2.5 xlc. */
+#if defined __cplusplus
+ template <class type> struct alignof_helper { char __slot1; type __slot2; };
+# define alignof_slot(type) offsetof (alignof_helper<type>, __slot2)
+#else
+# define alignof_slot(type) offsetof (struct { char __slot1; type __slot2; }, __slot2)
+#endif
+
+/* alignof_type (TYPE)
+ Determine the good alignment of an object of the given type at compile time.
+ Note that this is not necessarily the same as alignof_slot(type).
+ For example, with GNU C on x86 platforms and with clang on Linux/x86:
+ alignof_type(long long) = 8, but alignof_slot(long long) = 4.
+ And alignof_type(double) = 8, but
+ - when -malign-double is not specified: alignof_slot(double) = 4,
+ - when -malign-double is specified: alignof_slot(double) = 8.
+ Note: The result cannot be used as a value for an 'enum' constant,
+ due to bugs in HP-UX 10.20 cc and AIX 3.2.5 xlc. */
+#if defined __GNUC__ || defined __clang__ || defined __IBM__ALIGNOF__
+# define alignof_type __alignof__
+#else
+# define alignof_type alignof_slot
+#endif
+
+#endif /* _ALIGNOF_H */