1  /* Check stack alignment.  Generic version.
       2     Copyright (C) 2003-2023 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  
      22  int
      23  __attribute__ ((weak, noclone, noinline))
      24  is_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     })