fgetpos, fseek, fsetpos, ftell, rewind — reposition a stream
#include <stdio.h>
int
fseek( |
FILE *stream, |
| long offset, | |
int whence); |
long
ftell( |
FILE *stream); |
void
rewind( |
FILE *stream); |
int
fgetpos( |
FILE *stream, |
fpos_t *pos); |
int
fsetpos( |
FILE *stream, |
const fpos_t *pos); |
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, respectively. A successful call to the
fseek() function clears the
end-of-file indicator for the stream and undoes any effects
of the ungetc(3) function on the
same stream.
The ftell() function obtains
the current value of the file position indicator 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 clearerr(3)).
The fgetpos() and
fsetpos() functions are
alternate interfaces equivalent to ftell() and fseek() (with whence set to SEEK_SET), setting and storing the current
value of the file offset into or from the object referenced
by pos. On some
non-UNIX systems, an fpos_t object
may be a complex object and these routines may be the only
way to portably reposition a text stream.
The rewind() function
returns no value. Upon successful completion, fgetpos(), fseek(), fsetpos() return 0, and ftell() returns the current offset.
Otherwise, −1 is returned and errno is set to indicate the error.
The stream
specified is not a seekable stream.
The whence
argument to fseek() was
not SEEK_SET,
SEEK_END, or SEEK_CUR. Or: the resulting file
offset would be negative.
The functions fgetpos(),
fseek(), fsetpos(), and ftell() may also fail and set errno for any of the errors specified for
the routines fflush(3), fstat(2), lseek(2), and malloc(3).
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
|
|
Thread safety | MT-Safe |
This page is part of release 4.07 of the Linux man-pages project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
|
Copyright (c) 1990, 1991 The Regents of the University of California. All rights reserved. This code is derived from software contributed to Berkeley by Chris Torek and the American National Standards Committee X3, on Information Processing Systems. %%%LICENSE_START(BSD_4_CLAUSE_UCB) Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. All advertising materials mentioning features or use of this software must display the following acknowledgement: This product includes software developed by the University of California, Berkeley and its contributors. 4. Neither the name of the University nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. %%%LICENSE_END (#)fseek.3 6.11 (Berkeley) 6/29/91 Converted for Linux, Mon Nov 29 15:22:01 1993, faithcs.unc.edu |