sysdeps/generic/malloc-alignment.h

   1 /* Define MALLOC_ALIGNMENT for malloc.  Generic version.
   2    Copyright (C) 2017 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    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _GENERIC_MALLOC_ALIGNMENT_H
  20 #define _GENERIC_MALLOC_ALIGNMENT_H
  21
  22 /* MALLOC_ALIGNMENT is the minimum alignment for malloc'ed chunks.  It
  23    must be a power of two at least 2 * SIZE_SZ, even on machines for
  24    which smaller alignments would suffice. It may be defined as larger
  25    than this though. Note however that code and data structures are
  26    optimized for the case of 8-byte alignment.  */
  27 #define MALLOC_ALIGNMENT (2 * SIZE_SZ < __alignof__ (long double) \
  28                           ? __alignof__ (long double) : 2 * SIZE_SZ)
  29
  30
  31 #endif /* !defined(_GENERIC_MALLOC_ALIGNMENT_H) */