1/* Check stack alignment. Generic version.
2 Copyright (C) 2003-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C 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 The GNU C 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 the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <stdio.h>
20#include <stdint.h>
21
22int
23__attribute__ ((weak, noclone, noinline))
24is_aligned (void *p, int align)
25{
26 return (((uintptr_t) p) & (align - 1)) != 0;
27}
28
29#ifndef TEST_STACK_ALIGN_INIT
30# define TEST_STACK_ALIGN_INIT() 0
31#endif
32
33#define TEST_STACK_ALIGN() \
34 ({ \
35 double _d = 12.0; \
36 long double _ld = 15.0; \
37 int _ret = TEST_STACK_ALIGN_INIT (); \
38 \
39 printf ("double: %g %p %zu\n", _d, &_d, __alignof (double)); \
40 _ret += is_aligned (&_d, __alignof (double)); \
41 \
42 printf ("ldouble: %Lg %p %zu\n", _ld, &_ld, \
43 __alignof (long double)); \
44 _ret += is_aligned (&_ld, __alignof (long double)); \
45 _ret; \
46 })
47

source code of glibc/sysdeps/generic/tst-stack-align.h