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4349 Serge 1 
/*
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 * Copyright (c) 1990 The Regents of the University of California.
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms are permitted
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 * provided that the above copyright notice and this paragraph are
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 * duplicated in all such forms and that any documentation,
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 * advertising materials, and other materials related to such
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 * distribution and use acknowledge that the software was developed
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 * by the University of California, Berkeley.  The name of the
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 * University may not be used to endorse or promote products derived
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 * from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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 */
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/*
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FUNCTION
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<>, <>---return position in a stream or file
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INDEX
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	ftell
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INDEX
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	ftello
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INDEX
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	_ftell_r
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INDEX
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	_ftello_r
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ANSI_SYNOPSIS
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	#include
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	long ftell(FILE *<[fp]>);
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	off_t ftello(FILE *<[fp]>);
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	long _ftell_r(struct _reent *<[ptr]>, FILE *<[fp]>);
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	off_t _ftello_r(struct _reent *<[ptr]>, FILE *<[fp]>);
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TRAD_SYNOPSIS
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	#include
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	long ftell(<[fp]>)
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	FILE *<[fp]>;
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	off_t ftello(<[fp]>)
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	FILE *<[fp]>;
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	long _ftell_r(<[ptr]>, <[fp]>)
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	struct _reent *<[ptr]>;
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	FILE *<[fp]>;
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	off_t _ftello_r(<[ptr]>, <[fp]>)
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	struct _reent *<[ptr]>;
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	FILE *<[fp]>;
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DESCRIPTION
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Objects of type <> can have a ``position'' that records how much
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of the file your program has already read.  Many of the <> functions
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depend on this position, and many change it as a side effect.
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The result of <>/<> is the current position for a file
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identified by <[fp]>.  If you record this result, you can later
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use it with <>/<> to return the file to this
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position.  The difference between <> and <> is that
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<> returns <> and <> returns <>.
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In the current implementation, <>/<> simply uses a character
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count to represent the file position; this is the same number that
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would be recorded by <>.
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RETURNS
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<>/<> return the file position, if possible.  If they cannot do
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this, they return <<-1L>>.  Failure occurs on streams that do not support
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positioning; the global <> indicates this condition with the
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value <>.
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PORTABILITY
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<> is required by the ANSI C standard, but the meaning of its
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result (when successful) is not specified beyond requiring that it be
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acceptable as an argument to <>.  In particular, other
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conforming C implementations may return a different result from
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<> than what <> records.
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<> is defined by the Single Unix specification.
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No supporting OS subroutines are required.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "%W% (Berkeley) %G%";
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#endif /* LIBC_SCCS and not lint */
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/*
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 * ftell: return current offset.
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 */
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#include <_ansi.h>
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#include
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#include
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#include
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#include "local.h"
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long
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_DEFUN(_ftell_r, (ptr, fp),
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       struct _reent *ptr _AND
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       register FILE * fp)
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{
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  _fpos_t pos;
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  pos = _ftello_r (ptr, fp);
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  if ((long)pos != pos)
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    {
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      pos = -1;
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      ptr->_errno = EOVERFLOW;
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    }
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  return (long)pos;
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}
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#ifndef _REENT_ONLY
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long
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_DEFUN(ftell, (fp),
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       register FILE * fp)
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{
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  return _ftell_r (_REENT, fp);
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}
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#endif /* !_REENT_ONLY */