1  /* Copyright (C) 1993-2023 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     As a special exception, if you link the code in this file with
      19     files compiled with a GNU compiler to produce an executable,
      20     that does not cause the resulting executable to be covered by
      21     the GNU Lesser General Public License.  This exception does not
      22     however invalidate any other reasons why the executable file
      23     might be covered by the GNU Lesser General Public License.
      24     This exception applies to code released by its copyright holders
      25     in files containing the exception.  */
      26  
      27  /* We need to disable the redirect for __ftello64 for the alias
      28     definitions below to work.  */
      29  #define __ftello64 __ftello64_disable
      30  
      31  #include <stdio.h>
      32  #include <stdlib.h>
      33  #include <libioP.h>
      34  #include <errno.h>
      35  
      36  off_t
      37  __ftello (FILE *fp)
      38  {
      39    off64_t pos;
      40    CHECK_FILE (fp, -1L);
      41    _IO_acquire_lock (fp);
      42    pos = _IO_seekoff_unlocked (fp, 0, _IO_seek_cur, 0);
      43    if (_IO_in_backup (fp) && pos != _IO_pos_BAD)
      44      {
      45        if (fp->_mode <= 0)
      46  	pos -= fp->_IO_save_end - fp->_IO_save_base;
      47      }
      48    _IO_release_lock (fp);
      49    if (pos == _IO_pos_BAD)
      50      {
      51        if (errno == 0)
      52  	__set_errno (EIO);
      53        return -1L;
      54      }
      55    if ((off64_t) (off_t) pos != pos)
      56      {
      57        __set_errno (EOVERFLOW);
      58        return -1L;
      59      }
      60    return pos;
      61  }
      62  libc_hidden_def (__ftello)
      63  weak_alias (__ftello, ftello)
      64  
      65  #ifdef __OFF_T_MATCHES_OFF64_T
      66  weak_alias (__ftello, ftello64)
      67  # undef __ftello64
      68  strong_alias (__ftello, __ftello64)
      69  libc_hidden_ver (__ftello, __ftello64)
      70  #endif