sysdeps/unix/sysv/linux/posix_madvise.c

   1 /* Copyright (C) 2007 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <sysdep.h>
  20 #include <sys/mman.h>
  21
  22
  23 int
  24 posix_madvise (void *addr, size_t len, int advice)
  25 {
  26   /* We have one problem: the kernel's MADV_DONTNEED does not
  27      correspond to POSIX's POSIX_MADV_DONTNEED.  The former simply
  28      discards changes made to the memory without writing it back to
  29      disk, if this would be necessary.  The POSIX behavior does not
  30      allow this.  There is no functionality mapping the POSIX behavior
  31      so far so we ignore that advice for now.  */
  32   if (advice == POSIX_MADV_DONTNEED)
  33     return 0;
  34
  35   INTERNAL_SYSCALL_DECL (err);
  36   int result = INTERNAL_SYSCALL (madvise, err, 3, addr, len, advice);
  37   return INTERNAL_SYSCALL_ERRNO (result, err);
  38 }