From 28f540f45bbacd939bfd07f213bcad2bf730b1bf Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Sat, 18 Feb 1995 01:27:10 +0000 Subject: initial import --- stdio/ftell.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 stdio/ftell.c (limited to 'stdio/ftell.c') diff --git a/stdio/ftell.c b/stdio/ftell.c new file mode 100644 index 0000000000..d27eaf7598 --- /dev/null +++ b/stdio/ftell.c @@ -0,0 +1,54 @@ +/* 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 +#include +#include + +/* 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; +} -- cgit v1.2.3