mirror of
https://github.com/GnoConsortium/gno.git
synced 2024-12-22 14:30:29 +00:00
184 lines
4.7 KiB
Groff
184 lines
4.7 KiB
Groff
.\" Copyright (c) 1990, 1991, 1993
|
|
.\" 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.
|
|
.\"
|
|
.\" 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.
|
|
.\"
|
|
.\" @(#)fseek.3 8.1 (Berkeley) 6/4/93
|
|
.\"
|
|
.TH FSEEK 3 "15 September 1997" GNO "Library Routines"
|
|
.SH NAME
|
|
.BR fgetpos ,
|
|
.BR fseek ,
|
|
.BR fsetpos ,
|
|
.BR ftell ,
|
|
.BR rewind
|
|
\- reposition a stream
|
|
.SH SYNOPSIS
|
|
#include <stdio.h>
|
|
.sp 1
|
|
int \fBfseek\fR (FILE *\fIstream\fR, long \fIoffset\fR, int \fIwhence\fR);
|
|
.br
|
|
long \fBftell\fR (FILE *\fIstream\fR);
|
|
.br
|
|
void \fBrewind\fR (FILE *\fIstream\fR);
|
|
.br
|
|
int \fBfgetpos\fR (FILE *\fIstream\fR, fpos_t *\fIpos\fR);
|
|
.br
|
|
int \fBfsetpos\fR (FILE *\fIstream\fR, fpos_t *\fIpos\fR);
|
|
.SH DESCRIPTION
|
|
The
|
|
.BR fseek
|
|
function sets the file position indicator for the stream pointed
|
|
to by
|
|
.IR stream .
|
|
The new position, measured in bytes, is obtained by adding
|
|
.I offset
|
|
bytes to the position specified by
|
|
.IR whence .
|
|
If
|
|
.I whence
|
|
is set to
|
|
.BR SEEK_SET ,
|
|
.BR SEEK_CUR ,
|
|
or
|
|
.BR 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
|
|
.BR fseek
|
|
function clears the end-of-file indicator for the stream and undoes
|
|
any effects of the
|
|
.BR ungetc (3)
|
|
function on the same stream.
|
|
.LP
|
|
The
|
|
.BR ftell
|
|
function
|
|
obtains the current value of the file position indicator for the
|
|
stream pointed to by
|
|
.IR stream .
|
|
.LP
|
|
The
|
|
.BR rewind
|
|
function sets the file position indicator for the stream pointed
|
|
to by
|
|
.I stream
|
|
to the beginning of the file.
|
|
It is equivalent to:
|
|
.RS
|
|
(void) fseek(stream, 0L, SEEK_SET)
|
|
.RE
|
|
except that the error indicator for the stream is also cleared
|
|
(see
|
|
.BR clearerr (3)).
|
|
.LP
|
|
The
|
|
.BR fgetpos
|
|
and
|
|
.BR fsetpos
|
|
functions
|
|
are alternate interfaces equivalent to
|
|
.BR ftell
|
|
and
|
|
.BR fseek
|
|
(with whence set to \fBSEEK_SET\fR),
|
|
setting and storing the current value of
|
|
the file offset into or from the object referenced by
|
|
.IR pos .
|
|
On some non-UNIX
|
|
systems an
|
|
.B fpos_t
|
|
object may be a complex object
|
|
and these routines may be the only way to portably reposition a text stream.
|
|
.SH RETURN VALUES
|
|
The
|
|
.BR rewind
|
|
function
|
|
returns no value.
|
|
Upon successful completion,
|
|
.BR fgetpos ,
|
|
.BR fseek ,
|
|
.BR fsetpos
|
|
return 0,
|
|
and
|
|
.BR ftell
|
|
returns the current offset.
|
|
Otherwise, \-1 is returned and the global variable errno is set to
|
|
indicate the error.
|
|
.SH ERRORS
|
|
.RS
|
|
.IP \fBEBADF\fR
|
|
The
|
|
.I stream
|
|
specified
|
|
is not a seekable stream.
|
|
.IP \fBEINVAL\fR
|
|
The
|
|
.I whence
|
|
argument to
|
|
.BR fseek
|
|
was not
|
|
.BR SEEK_SET ,
|
|
.BR SEEK_END ,
|
|
or
|
|
.BR SEEK_CUR .
|
|
.RE
|
|
.LP
|
|
The function
|
|
.BR fgetpos ,
|
|
.BR fseek ,
|
|
.BR fsetpos ,
|
|
and
|
|
.BR ftell
|
|
may also fail and set
|
|
.IR errno
|
|
for any of the errors specified for the routines
|
|
.BR fflush (3),
|
|
.BR fstat (2),
|
|
.BR lseek (2),
|
|
and
|
|
.BR malloc (3).
|
|
.SH SEE ALSO
|
|
.BR lseek (2)
|
|
.SH STANDARDS
|
|
The
|
|
.BR fgetpos ,
|
|
.BR fsetpos ,
|
|
.BR fseek ,
|
|
.BR ftell ,
|
|
and
|
|
.BR rewind
|
|
functions
|
|
conform to ANSI/C.
|