56 lines
2.0 KiB
Plaintext
56 lines
2.0 KiB
Plaintext
|
'\"
|
||
|
|
'\" Copyright (c) 1993 The Regents of the University of California.
|
||
|
|
'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
|
||
|
|
'\"
|
||
|
|
'\" See the file "license.terms" for information on usage and redistribution
|
||
|
|
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
|
||
|
|
'\"
|
||
|
|
'\" SCCS: @(#) seek.n 1.10 96/08/26 13:00:14
|
||
|
|
'\"
|
||
|
|
.so man.macros
|
||
|
|
.TH seek n 7.5 Tcl "Tcl Built-In Commands"
|
||
|
|
.BS
|
||
|
|
'\" Note: do not modify the .SH NAME line immediately below!
|
||
|
|
.SH NAME
|
||
|
|
seek \- Change the access position for an open channel
|
||
|
|
.SH SYNOPSIS
|
||
|
|
\fBseek \fIchannelId offset \fR?\fIorigin\fR?
|
||
|
|
.BE
|
||
|
|
|
||
|
|
.SH DESCRIPTION
|
||
|
|
.PP
|
||
|
|
Changes the current access position for \fIchannelId\fR.
|
||
|
|
\fIChannelId\fR must be a channel identifier such as returned from a
|
||
|
|
previous invocation of \fBopen\fR or \fBsocket\fR.
|
||
|
|
The \fIoffset\fR and \fIorigin\fR
|
||
|
|
arguments specify the position at which the next read or write will occur
|
||
|
|
for \fIchannelId\fR. \fIOffset\fR must be an integer (which may be
|
||
|
|
negative) and \fIorigin\fR must be one of the following:
|
||
|
|
.TP 10
|
||
|
|
\fBstart\fR
|
||
|
|
The new access position will be \fIoffset\fR bytes from the start
|
||
|
|
of the underlying file or device.
|
||
|
|
.TP 10
|
||
|
|
\fBcurrent\fR
|
||
|
|
The new access position will be \fIoffset\fR bytes from the current
|
||
|
|
access position; a negative \fIoffset\fR moves the access position
|
||
|
|
backwards in the underlying file or device.
|
||
|
|
.TP 10
|
||
|
|
\fBend\fR
|
||
|
|
The new access position will be \fIoffset\fR bytes from the end of
|
||
|
|
the file or device. A negative \fIoffset\fR places the access position
|
||
|
|
before the end of file, and a positive \fIoffset\fR places the access
|
||
|
|
position after the end of file.
|
||
|
|
.LP
|
||
|
|
The \fIorigin\fR argument defaults to \fBstart\fR.
|
||
|
|
.PP
|
||
|
|
The command flushes all buffered output for the channel before the command
|
||
|
|
returns, even if the channel is in nonblocking mode.
|
||
|
|
It also discards any buffered and unread input.
|
||
|
|
This command returns an empty string.
|
||
|
|
An error occurs if this command is applied to channels whose underlying
|
||
|
|
file or device does not support seeking.
|
||
|
|
|
||
|
|
.SH KEYWORDS
|
||
|
|
access position, file, seek
|