lib/ftell.c

   1 /* An ftell() function that works around platform bugs.
   2    Copyright (C) 2007-2024 Free Software Foundation, Inc.
   3
   4    This file is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation; either version 2.1 of the
   7    License, or (at your option) any later version.
   8
   9    This file 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
  12    GNU Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18
  19 /* Specification.  */
  20 #include <stdio.h>
  21
  22 #include <errno.h>
  23 #include <limits.h>
  24
  25 long
  26 ftell (FILE *fp)
  27 {
  28   /* Use the replacement ftello function with all its workarounds.  */
  29   off_t offset = ftello (fp);
  30   if (LONG_MIN <= offset && offset <= LONG_MAX)
  31     return /* (long) */ offset;
  32   else
  33     {
  34       errno = EOVERFLOW;
  35       return -1;
  36     }
  37 }