posix/pread.c

   1 /* Copyright (C) 1991, 1995, 1996, 1997, 1999 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 <errno.h>
  20 #include <unistd.h>
  21
  22 /* Read NBYTES into BUF from FD at the given position OFFSET without
  23    changing the file pointer.  Return the number read or -1.  */
  24 ssize_t
  25 __libc_pread (int fd, void *buf, size_t nbytes, off_t offset)
  26 {
  27   if (nbytes == 0)
  28     return 0;
  29   if (fd < 0)
  30     {
  31       __set_errno (EBADF);
  32       return -1;
  33     }
  34   if (buf == NULL || offset < 0)
  35     {
  36       __set_errno (EINVAL);
  37       return -1;
  38     }
  39
  40   __set_errno (ENOSYS);
  41   return -1;
  42 }
  43 strong_alias (__libc_pread, __pread)
  44 weak_alias (__libc_pread, pread)
  45 stub_warning (pread)
  46 #include <stub-tag.h>