1996-06-26 06:06:43 +00:00
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'\"
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'\" Copyright (c) 1993 The Regents of the University of California.
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'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
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'\"
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'\" See the file "license.terms" for information on usage and redistribution
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'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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'\"
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1997-07-25 19:27:55 +00:00
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'\" SCCS: @(#) seek.n 1.10 96/08/26 13:00:14
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1996-06-26 06:06:43 +00:00
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'\"
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.so man.macros
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.TH seek n 7.5 Tcl "Tcl Built-In Commands"
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.BS
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'\" Note: do not modify the .SH NAME line immediately below!
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.SH NAME
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seek \- Change the access position for an open channel
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.SH SYNOPSIS
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\fBseek \fIchannelId offset \fR?\fIorigin\fR?
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.BE
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.SH DESCRIPTION
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.PP
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Changes the current access position for \fIchannelId\fR.
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\fIChannelId\fR must be a channel identifier such as returned from a
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previous invocation of \fBopen\fR or \fBsocket\fR.
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The \fIoffset\fR and \fIorigin\fR
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arguments specify the position at which the next read or write will occur
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for \fIchannelId\fR. \fIOffset\fR must be an integer (which may be
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negative) and \fIorigin\fR must be one of the following:
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.TP 10
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\fBstart\fR
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The new access position will be \fIoffset\fR bytes from the start
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of the underlying file or device.
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.TP 10
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\fBcurrent\fR
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The new access position will be \fIoffset\fR bytes from the current
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access position; a negative \fIoffset\fR moves the access position
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backwards in the underlying file or device.
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.TP 10
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\fBend\fR
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The new access position will be \fIoffset\fR bytes from the end of
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the file or device. A negative \fIoffset\fR places the access position
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before the end of file, and a positive \fIoffset\fR places the access
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position after the end of file.
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.LP
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The \fIorigin\fR argument defaults to \fBstart\fR.
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.PP
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The command flushes all buffered output for the channel before the command
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returns, even if the channel is in nonblocking mode.
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It also discards any buffered and unread input.
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This command returns an empty string.
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An error occurs if this command is applied to channels whose underlying
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file or device does not support seeking.
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.SH KEYWORDS
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access position, file, seek
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