sysdeps/unix/sysv/linux/readahead.c

   1 /* Provide kernel hint to read ahead.
   2    Copyright (C) 2002, 2003, 2004, 2007 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 <errno.h>
  21 #include <fcntl.h>
  22 #include <sys/types.h>
  23
  24 #include <sysdep.h>
  25 #include <sys/syscall.h>
  26
  27
  28 #ifdef __NR_readahead
  29
  30 ssize_t
  31 __readahead (int fd, off64_t offset, size_t count)
  32 {
  33   return INLINE_SYSCALL (readahead, 4, fd,
  34                          __LONG_LONG_PAIR ((off_t) (offset >> 32),
  35                                            (off_t) (offset & 0xffffffff)),
  36                          count);
  37 }
  38 #else
  39 ssize_t
  40 __readahead (int fd, off64_t offset, size_t count)
  41 {
  42   __set_errno (ENOSYS);
  43   return -1;
  44 }
  45 stub_warning (readahead)
  46
  47 # include <stub-tag.h>
  48 #endif
  49
  50 weak_alias (__readahead, readahead)