| /* Copyright (C) 1991, 1992, 1994, 1996, 1997 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Library General Public License as |
| published by the Free Software Foundation; either version 2 of the |
| License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Library General Public License for more details. |
| |
| You should have received a copy of the GNU Library General Public |
| License along with the GNU C Library; see the file COPYING.LIB. If not, |
| write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| #include <errno.h> |
| #include <stdio.h> |
| |
| /* Return the offset in bytes from the beginning |
| of the file of the file position of STREAM. */ |
| long int |
| ftell (stream) |
| FILE *stream; |
| { |
| long int pos; |
| |
| if (!__validfp (stream)) |
| { |
| __set_errno (EINVAL); |
| return -1L; |
| } |
| |
| if (__stdio_check_offset (stream) == EOF) |
| return -1L; |
| |
| /* Start with the file position associated with the beginning |
| of our buffer. */ |
| pos = stream->__target; |
| |
| if (stream->__pushed_back) |
| /* ungetc was just called, so our real buffer pointer is squirreled |
| away in STREAM->__pushback_bufp, not in STREAM->__bufp as normal. |
| Calling ungetc is supposed to decrement the file position. ANSI |
| says the file position is unspecified if you ungetc when the |
| position is zero; -1 seems as good as anything to me. */ |
| pos += stream->__pushback_bufp - stream->__buffer - 1; |
| else |
| pos += stream->__bufp - stream->__buffer; |
| |
| return pos; |
| } |