GNU libmicrohttpd 0.9.77
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mhd_align.h
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1/*
2 This file is part of libmicrohttpd
3 Copyright (C) 2021 Karlson2k (Evgeny Grin)
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with this library.
17 If not, see <http://www.gnu.org/licenses/>.
18*/
19
26#ifndef MHD_ALIGN_H
27#define MHD_ALIGN_H 1
28
29#include "mhd_options.h"
30#include <stdint.h>
31#ifdef HAVE_STDDEF_H
32#include <stddef.h>
33#endif
34
35#ifdef HAVE_C_ALIGNOF
36#ifdef HAVE_STDALIGN_H
37#include <stdalign.h>
38#endif /* HAVE_STDALIGN_H */
39#define _MHD_ALIGNOF(type) alignof(type)
40#endif /* HAVE_C_ALIGNOF */
41
42#ifndef _MHD_ALIGNOF
43#if defined(_MSC_VER) && ! defined(__clang__) && _MSC_VER >= 1700
44#define _MHD_ALIGNOF(type) __alignof(type)
45#endif /* _MSC_VER >= 1700 */
46#endif /* !_MHD_ALIGNOF */
47
48#ifdef _MHD_ALIGNOF
49#if (defined(__GNUC__) && __GNUC__ < 4 && __GNUC_MINOR__ < 9 && \
50 ! defined(__clang__)) || \
51 (defined(__clang__) && __clang_major__ < 8) || \
52 (defined(__clang__) && __clang_major__ < 11 && \
53 defined(__apple_build_version__))
54/* GCC before 4.9 and clang before 8.0 have incorrect implementation of 'alignof()'
55 which returns preferred alignment instead of minimal required alignment */
56#define _MHD_ALIGNOF_UNRELIABLE 1
57#endif
58
59#if defined(_MSC_VER) && ! defined(__clang__) && _MSC_VER < 1900
60/* MSVC has the same problem as old GCC versions:
61 '__alignof()' may return "preferred" alignment instead of "required". */
62#define _MHD_ALIGNOF_UNRELIABLE 1
63#endif /* _MSC_VER < 1900 */
64#endif /* _MHD_ALIGNOF */
65
66
67#ifdef offsetof
68#define _MHD_OFFSETOF(strct, membr) offsetof(strct, membr)
69#else /* ! offsetof */
70#define _MHD_OFFSETOF(strct, membr) (size_t)(((char*)&(((strct*)0)->membr)) - \
71 ((char*)((strct*)0)))
72#endif /* ! offsetof */
73
74/* Provide a limited set of alignment macros */
75/* The set could be extended as needed */
76#if defined(_MHD_ALIGNOF) && ! defined(_MHD_ALIGNOF_UNRELIABLE)
77#define _MHD_UINT32_ALIGN _MHD_ALIGNOF(uint32_t)
78#define _MHD_UINT64_ALIGN _MHD_ALIGNOF(uint64_t)
79#else /* ! _MHD_ALIGNOF */
81{
82 char dummy;
83 uint32_t ui32;
84};
85#define _MHD_UINT32_ALIGN \
86 _MHD_OFFSETOF(struct _mhd_dummy_uint32_offset_test, ui32)
87
89{
90 char dummy;
91 uint64_t ui64;
92};
93#define _MHD_UINT64_ALIGN \
94 _MHD_OFFSETOF(struct _mhd_dummy_uint64_offset_test, ui64)
95#endif /* ! _MHD_ALIGNOF */
96
97#endif /* ! MHD_ALIGN_H */
additional automatic macros for MHD_config.h