mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-23 13:30:06 +00:00
55 lines
1.8 KiB
C
55 lines
1.8 KiB
C
/* Copyright (C) 1991, 1992, 1994 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., 675 Mass Ave,
|
|
Cambridge, MA 02139, USA. */
|
|
|
|
#include <ansidecl.h>
|
|
#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
|
|
DEFUN(ftell, (stream), FILE *stream)
|
|
{
|
|
long int pos;
|
|
|
|
if (!__validfp (stream))
|
|
{
|
|
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;
|
|
}
|