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/*
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
/*
FUNCTION
<<ftello64>>---return position in a stream or file
INDEX
ftello64
INDEX
_ftello64_r
ANSI_SYNOPSIS
#include <stdio.h>
_off64_t ftello64(FILE *<[fp]>);
_off64_t _ftello64_r(struct _reent *<[ptr]>, FILE *<[fp]>);
TRAD_SYNOPSIS
#include <stdio.h>
_off64_t ftello64(<[fp]>)
FILE *<[fp]>;
_off64_t _ftello64_r(<[ptr]>, <[fp]>)
struct _reent *<[ptr]>;
FILE *<[fp]>;
DESCRIPTION
Objects of type <<FILE>> can have a ``position'' that records how much
of the file your program has already read. Many of the <<stdio>> functions
depend on this position, and many change it as a side effect.
The result of <<ftello64>> is the current position for a large file
identified by <[fp]>. If you record this result, you can later
use it with <<fseeko64>> to return the file to this
position. The difference between <<ftello>> and <<ftello64>> is that
<<ftello>> returns <<off_t>> and <<ftello64>> is designed to work
for large files (>2GB) and returns <<_off64_t>>.
In the current implementation, <<ftello64>> simply uses a character
count to represent the file position; this is the same number that
would be recorded by <<fgetpos64>>.
The function exists only if the __LARGE64_FILES flag is defined.
An error occurs if the <[fp]> was not opened via <<fopen64>>.
RETURNS
<<ftello64>> returns the file position, if possible. If it cannot do
this, it returns <<-1>>. Failure occurs on streams that do not support
positioning or not opened via <<fopen64>>; the global <<errno>> indicates
this condition with the value <<ESPIPE>>.
PORTABILITY
<<ftello64>> is a glibc extension.
No supporting OS subroutines are required.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "%W% (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */
/*
* ftello64: return current offset.
*/
#include <stdio.h>
#include <errno.h>
#include "local.h"
#ifdef __LARGE64_FILES
_off64_t
_DEFUN (_ftello64_r, (ptr, fp),
struct _reent *ptr _AND
register FILE * fp)
{
_fpos64_t pos;
/* Only do 64-bit tell on large file. */
if (!(fp->_flags & __SL64))
return (_off64_t) _ftello_r (ptr, fp);
/* Ensure stdio is set up. */
CHECK_INIT (ptr, fp);
_flockfile(fp);
if (fp->_seek64 == NULL)
{
ptr->_errno = ESPIPE;
_funlockfile(fp);
return -1L;
}
/* Find offset of underlying I/O object, then adjust for buffered
bytes. Flush a write stream, since the offset may be altered if
the stream is appending. Do not flush a read stream, since we
must not lose the ungetc buffer. */
if (fp->_flags & __SWR)
_fflush_r (ptr, fp);
if (fp->_flags & __SOFF)
pos = fp->_offset;
else
{
pos = fp->_seek64 (ptr, fp->_cookie, (_fpos64_t) 0, SEEK_CUR);
if (pos == -1L)
{
_funlockfile(fp);
return pos;
}
}
if (fp->_flags & __SRD)
{
/*
* Reading. Any unread characters (including
* those from ungetc) cause the position to be
* smaller than that in the underlying object.
*/
pos -= fp->_r;
if (HASUB (fp))
pos -= fp->_ur;
}
else if (fp->_flags & __SWR && fp->_p != NULL)
{
/*
* Writing. Any buffered characters cause the
* position to be greater than that in the
* underlying object.
*/
pos += fp->_p - fp->_bf._base;
}
_funlockfile(fp);
return pos;
}
#ifndef _REENT_ONLY
_off64_t
_DEFUN (ftello64, (fp),
register FILE * fp)
{
return _ftello64_r (_REENT, fp);
}
#endif /* !_REENT_ONLY */
#endif /* __LARGE64_FILES */
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