src/getpagesize.h

   1 /* Emulate getpagesize on systems that lack it.
   2    Copyright (C) 1986, 1992, 1995, 2001-2018 Free Software Foundation,
   3    Inc.
   4
   5 This file is part of GNU Emacs.
   6
   7 GNU Emacs is free software: you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation, either version 3 of the License, or (at
  10 your option) any later version.
  11
  12 GNU Emacs is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
  19
  20 #ifndef HAVE_GETPAGESIZE
  21
  22 # include <unistd.h>
  23
  24 # ifdef _SC_PAGESIZE
  25 #  define getpagesize() sysconf (_SC_PAGESIZE)
  26 # else /* no _SC_PAGESIZE */
  27 #  ifdef HAVE_SYS_PARAM_H
  28 #   include <sys/param.h>
  29 #   ifdef EXEC_PAGESIZE
  30 #    define getpagesize() EXEC_PAGESIZE
  31 #   else /* no EXEC_PAGESIZE */
  32 #    ifdef NBPG
  33 #     define getpagesize() NBPG * CLSIZE
  34 #     ifndef CLSIZE
  35 #      define CLSIZE 1
  36 #     endif /* no CLSIZE */
  37 #    else /* no NBPG */
  38 #      ifdef PAGESIZE
  39 #       define getpagesize() PAGESIZE
  40 #      endif /* PAGESIZE */
  41 #    endif /* no NBPG */
  42 #   endif /* no EXEC_PAGESIZE */
  43 #  else /* no HAVE_SYS_PARAM_H */
  44 #   define getpagesize() 8192   /* punt totally */
  45 #  endif /* no HAVE_SYS_PARAM_H */
  46 # endif /* no _SC_PAGESIZE */
  47
  48 #endif /* no HAVE_GETPAGESIZE */