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[debian/tar] / gnu / stdalign.in.h

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+/* -*- buffer-read-only: t -*- vi: set ro: */
+/* DO NOT EDIT! GENERATED AUTOMATICALLY! */
+/* A substitute for ISO C11 <stdalign.h>.
+
+   Copyright 2011-2013 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 3, 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, see <http://www.gnu.org/licenses/>.  */
+
+/* Written by Paul Eggert and Bruno Haible.  */
+
+#ifndef _GL_STDALIGN_H
+#define _GL_STDALIGN_H
+
+/* ISO C11 <stdalign.h> for platforms that lack it.
+
+   References:
+   ISO C11 (latest free draft
+   <http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf>)
+   sections 6.5.3.4, 6.7.5, 7.15.
+   C++11 (latest free draft
+   <http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3242.pdf>)
+   section 18.10. */
+
+/* alignof (TYPE), also known as _Alignof (TYPE), yields the alignment
+   requirement of a structure member (i.e., slot or field) that is of
+   type TYPE, as an integer constant expression.
+
+   This differs from GCC's __alignof__ operator, which can yield a
+   better-performing alignment for an object of that type.  For
+   example, on x86 with GCC, __alignof__ (double) and __alignof__
+   (long long) are 8, whereas alignof (double) and alignof (long long)
+   are 4 unless the option '-malign-double' is used.
+
+   The result cannot be used as a value for an 'enum' constant, if you
+   want to be portable to HP-UX 10.20 cc and AIX 3.2.5 xlc.  */
+#include <stddef.h>
+#if defined __cplusplus
+   template <class __t> struct __alignof_helper { char __a; __t __b; };
+# define _Alignof(type) offsetof (__alignof_helper<type>, __b)
+#else
+# define _Alignof(type) offsetof (struct { char __a; type __b; }, __b)
+#endif
+#define alignof _Alignof
+#define __alignof_is_defined 1
+
+/* alignas (A), also known as _Alignas (A), aligns a variable or type
+   to the alignment A, where A is an integer constant expression.  For
+   example:
+
+      int alignas (8) foo;
+      struct s { int a; int alignas (8) bar; };
+
+   aligns the address of FOO and the offset of BAR to be multiples of 8.
+
+   A should be a power of two that is at least the type's alignment
+   and at most the implementation's alignment limit.  This limit is
+   2**28 on typical GNUish hosts, and 2**13 on MSVC.  To be portable
+   to MSVC through at least version 10.0, A should be an integer
+   constant, as MSVC does not support expressions such as 1 << 3.
+   To be portable to Sun C 5.11, do not align auto variables to
+   anything stricter than their default alignment.
+
+   The following C11 requirements are not supported here:
+
+     - If A is zero, alignas has no effect.
+     - alignas can be used multiple times; the strictest one wins.
+     - alignas (TYPE) is equivalent to alignas (alignof (TYPE)).
+
+   */
+
+#if __GNUC__ || __IBMC__ || __IBMCPP__ || 0x5110 <= __SUNPRO_C
+# define _Alignas(a) __attribute__ ((__aligned__ (a)))
+#elif 1300 <= _MSC_VER
+# define _Alignas(a) __declspec (align (a))
+#endif
+#ifdef _Alignas
+# define alignas _Alignas
+# define __alignas_is_defined 1
+#endif
+
+#endif /* _GL_STDALIGN_H */