sysdeps/unix/sysv/linux/getpagesize.c

   1 /* Copyright (C) 1991,1992,1995-1997,2000,2002,2004,2010
   2    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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <assert.h>
  21 #include <unistd.h>
  22 #include <sys/param.h>
  23
  24 #include <ldsodefs.h>
  25 #include <kernel-features.h>
  26
  27 /* Return the system page size.  */
  28 int
  29 __getpagesize ()
  30 {
  31 #ifdef __ASSUME_AT_PAGESIZE
  32   assert (GLRO(dl_pagesize) != 0);
  33   return GLRO(dl_pagesize);
  34 #else
  35   if (GLRO(dl_pagesize) != 0)
  36     return GLRO(dl_pagesize);
  37
  38 # ifdef EXEC_PAGESIZE
  39   return EXEC_PAGESIZE;
  40 # else  /* No EXEC_PAGESIZE.  */
  41 #  ifdef NBPG
  42 #   ifndef CLSIZE
  43 #    define CLSIZE      1
  44 #   endif       /* No CLSIZE.  */
  45   return NBPG * CLSIZE;
  46 #  else /* No NBPG.  */
  47   return NBPC;
  48 #  endif        /* NBPG.  */
  49 # endif /* EXEC_PAGESIZE.  */
  50 #endif
  51 }
  52 libc_hidden_def (__getpagesize)
  53 weak_alias (__getpagesize, getpagesize)