io/lseek.c

   1 /* Copyright (C) 1991-2022 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, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <unistd.h>
  20 #include <sys/types.h>
  21
  22 /* Seek to OFFSET on FD, starting from WHENCE.  */
  23 off_t
  24 __libc_lseek (int fd, off_t offset, int whence)
  25 {
  26   if (fd < 0)
  27     {
  28       __set_errno (EBADF);
  29       return -1;
  30     }
  31   switch (whence)
  32     {
  33     case SEEK_SET:
  34     case SEEK_CUR:
  35     case SEEK_END:
  36       break;
  37     default:
  38       __set_errno (EINVAL);
  39       return -1;
  40     }
  41
  42   __set_errno (ENOSYS);
  43   return -1;
  44 }
  45 weak_alias (__libc_lseek, __lseek)
  46 weak_alias (__libc_lseek, lseek)
  47 stub_warning (lseek)
  48
  49 libc_hidden_def (__lseek)