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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 16:11:47 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 16:11:47 +0000 |
commit | 758f820bcc0f68aeebac1717e537ca13a320b909 (patch) | |
tree | 48111ece75cf4f98316848b37a7e26356e00669e /lib/alignof.h | |
parent | Initial commit. (diff) | |
download | coreutils-758f820bcc0f68aeebac1717e537ca13a320b909.tar.xz coreutils-758f820bcc0f68aeebac1717e537ca13a320b909.zip |
Adding upstream version 9.1.upstream/9.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'lib/alignof.h')
-rw-r--r-- | lib/alignof.h | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/lib/alignof.h b/lib/alignof.h new file mode 100644 index 0000000..3f4a542 --- /dev/null +++ b/lib/alignof.h @@ -0,0 +1,52 @@ +/* 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 */ |