129 lines
3.7 KiB
C
129 lines
3.7 KiB
C
/*
|
|
* 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
|
|
<<fseek>>, <<fseeko>>---set file position
|
|
|
|
INDEX
|
|
fseek
|
|
INDEX
|
|
fseeko
|
|
INDEX
|
|
_fseek_r
|
|
INDEX
|
|
_fseeko_r
|
|
|
|
ANSI_SYNOPSIS
|
|
#include <stdio.h>
|
|
int fseek(FILE *<[fp]>, long <[offset]>, int <[whence]>)
|
|
int fseeko(FILE *<[fp]>, off_t <[offset]>, int <[whence]>)
|
|
int _fseek_r(struct _reent *<[ptr]>, FILE *<[fp]>,
|
|
long <[offset]>, int <[whence]>)
|
|
int _fseeko_r(struct _reent *<[ptr]>, FILE *<[fp]>,
|
|
off_t <[offset]>, int <[whence]>)
|
|
|
|
TRAD_SYNOPSIS
|
|
#include <stdio.h>
|
|
int fseek(<[fp]>, <[offset]>, <[whence]>)
|
|
FILE *<[fp]>;
|
|
long <[offset]>;
|
|
int <[whence]>;
|
|
|
|
int fseeko(<[fp]>, <[offset]>, <[whence]>)
|
|
FILE *<[fp]>;
|
|
off_t <[offset]>;
|
|
int <[whence]>;
|
|
|
|
int _fseek_r(<[ptr]>, <[fp]>, <[offset]>, <[whence]>)
|
|
struct _reent *<[ptr]>;
|
|
FILE *<[fp]>;
|
|
long <[offset]>;
|
|
int <[whence]>;
|
|
|
|
int _fseeko_r(<[ptr]>, <[fp]>, <[offset]>, <[whence]>)
|
|
struct _reent *<[ptr]>;
|
|
FILE *<[fp]>;
|
|
off_t <[offset]>;
|
|
int <[whence]>;
|
|
|
|
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.
|
|
|
|
You can use <<fseek>>/<<fseeko>> to set the position for the file identified by
|
|
<[fp]>. The value of <[offset]> determines the new position, in one
|
|
of three ways selected by the value of <[whence]> (defined as macros
|
|
in `<<stdio.h>>'):
|
|
|
|
<<SEEK_SET>>---<[offset]> is the absolute file position (an offset
|
|
from the beginning of the file) desired. <[offset]> must be positive.
|
|
|
|
<<SEEK_CUR>>---<[offset]> is relative to the current file position.
|
|
<[offset]> can meaningfully be either positive or negative.
|
|
|
|
<<SEEK_END>>---<[offset]> is relative to the current end of file.
|
|
<[offset]> can meaningfully be either positive (to increase the size
|
|
of the file) or negative.
|
|
|
|
See <<ftell>>/<<ftello>> to determine the current file position.
|
|
|
|
RETURNS
|
|
<<fseek>>/<<fseeko>> return <<0>> when successful. On failure, the
|
|
result is <<EOF>>. The reason for failure is indicated in <<errno>>:
|
|
either <<ESPIPE>> (the stream identified by <[fp]> doesn't support
|
|
repositioning) or <<EINVAL>> (invalid file position).
|
|
|
|
PORTABILITY
|
|
ANSI C requires <<fseek>>.
|
|
|
|
<<fseeko>> is defined by the Single Unix specification.
|
|
|
|
Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
|
|
<<lseek>>, <<read>>, <<sbrk>>, <<write>>.
|
|
*/
|
|
|
|
#include <_ansi.h>
|
|
#include <reent.h>
|
|
#include <stdio.h>
|
|
#include <errno.h>
|
|
#include "local.h"
|
|
|
|
int
|
|
_DEFUN(_fseek_r, (ptr, fp, offset, whence),
|
|
struct _reent *ptr _AND
|
|
register FILE *fp _AND
|
|
long offset _AND
|
|
int whence)
|
|
{
|
|
return _fseeko_r (ptr, fp, offset, whence);
|
|
}
|
|
|
|
#ifndef _REENT_ONLY
|
|
|
|
int
|
|
_DEFUN(fseek, (fp, offset, whence),
|
|
register FILE *fp _AND
|
|
long offset _AND
|
|
int whence)
|
|
{
|
|
return _fseek_r (_REENT, fp, offset, whence);
|
|
}
|
|
|
|
#endif /* !_REENT_ONLY */
|