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FSEEK(3)		 BSD Library Functions Manual		      FSEEK(3)

     fgetpos, fseek, fseeko, fsetpos, ftell, ftello, rewind -- reposition a

     Standard C	Library	(libc, -lc)

     #include <stdio.h>

     fseek(FILE	*stream, long offset, int whence);

     ftell(FILE	*stream);

     rewind(FILE *stream);

     fgetpos(FILE * restrict stream, fpos_t * restrict pos);

     fsetpos(FILE *stream, const fpos_t	*pos);

     #include <sys/types.h>

     fseeko(FILE *stream, off_t	offset,	int whence);

     ftello(FILE *stream);

     The fseek() function sets the file	position indicator for the stream
     pointed to	by stream.  The	new position, measured in bytes, is obtained
     by	adding offset bytes to the position specified by whence.  If whence is
     set to SEEK_SET, SEEK_CUR,	or SEEK_END, the offset	is relative to the
     start of the file,	the current position indicator,	or end-of-file,	re-
     spectively.  A successful call to the fseek() function clears the end-of-
     file indicator for	the stream and undoes any effects of the ungetc(3) and
     ungetwc(3)	functions on the same stream.

     The ftell() function obtains the current value of the file	position indi-
     cator for the stream pointed to by	stream.

     The rewind() function sets	the file position indicator for	the stream
     pointed to	by stream to the beginning of the file.	 It is equivalent to:

	   (void)fseek(stream, 0L, SEEK_SET)

     except that the error indicator for the stream is also cleared (see

     Since rewind() does not return a value, an	application wishing to detect
     errors should clear errno,	then call rewind(), and	if errno is non-zero,
     assume an error has occurred.

     The fseeko() function is identical	to fseek(), except it takes an off_t
     argument instead of a long.  Likewise, the	ftello() function is identical
     to	ftell(), except	it returns an off_t.

     The fgetpos() and fsetpos() functions are alternate interfaces for	re-
     trieving and setting the current position in the file, similar to ftell()
     and fseek(), except that the current position is stored in	an opaque ob-
     ject of type fpos_t pointed to by pos.  These functions provide a porta-
     ble way to	seek to	offsets	larger than those that can be represented by a
     long int.	They may also store additional state information in the	fpos_t
     object to facilitate seeking within files containing multibyte characters
     with state-dependent encodings.  Although fpos_t has traditionally	been
     an	integral type, applications cannot assume that it is; in particular,
     they must not perform arithmetic on objects of this type.

     If	the stream is a	wide character stream (see fwide(3)), the position
     specified by the combination of offset and	whence must contain the	first
     byte of a multibyte sequence.

     The rewind() function returns no value.

     The fgetpos(), fseek(), fseeko(), and fsetpos() functions return the
     value 0 if	successful; otherwise the value	-1 is returned and the global
     variable errno is set to indicate the error.

     Upon successful completion, ftell() and ftello() return the current off-
     set.  Otherwise, -1 is returned and the global variable errno is set to
     indicate the error.

     [EBADF]		The stream argument is not a seekable stream.

     [EINVAL]		The whence argument is invalid or the resulting	file-
			position indicator would be set	to a negative value.

     [EOVERFLOW]	The resulting file offset would	be a value which can-
			not be represented correctly in	an object of type
			off_t for fseeko() and ftello()	or long	for fseek()
			and ftell().

     [ESPIPE]		The file descriptor underlying stream is associated
			with a pipe or FIFO or file-position indicator value
			is unspecified (see ungetc(3)).

     The functions fgetpos(), fseek(), fseeko(), fsetpos(), ftell(), ftello(),
     and rewind() may also fail	and set	errno for any of the errors specified
     for the routines fflush(3), fstat(2), lseek(2), and malloc(3).

     lseek(2), clearerr(3), fwide(3), ungetc(3), ungetwc(3)

     The fgetpos(), fsetpos(), fseek(),	ftell(), and rewind() functions	con-
     form to ISO/IEC 9899:1990 ("ISO C90").

     The fseeko() and ftello() functions conform to IEEE Std 1003.1-2001

BSD				March 19, 2004				   BSD


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