diff options
Diffstat (limited to 'doc/tell.n')
| -rw-r--r-- | doc/tell.n | 13 |
1 files changed, 3 insertions, 10 deletions
@@ -5,10 +5,8 @@ '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" -'\" RCS: @(#) $Id: tell.n,v 1.5.8.1 2004/10/27 14:43:14 dkf Exp $ -'\" -.so man.macros .TH tell n 8.1 Tcl "Tcl Built-In Commands" +.so man.macros .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME @@ -16,26 +14,23 @@ tell \- Return current access position for an open channel .SH SYNOPSIS \fBtell \fIchannelId\fR .BE - .SH DESCRIPTION .PP -.VS 8.1 Returns an integer string giving the current access position in \fIchannelId\fR. This value returned is a byte offset that can be passed to \fBseek\fR in order to set the channel to a particular position. Note that this value is in terms of bytes, not characters like \fBread\fR. -.VE 8.1 The value returned is -1 for channels that do not support seeking. .PP -.VS \fIChannelId\fR must be an identifier for an open channel such as a Tcl standard channel (\fBstdin\fR, \fBstdout\fR, or \fBstderr\fR), the return value from an invocation of \fBopen\fR or \fBsocket\fR, or the result of a channel creation command provided by a Tcl extension. -.VE .SH EXAMPLE +.PP Read a line from a file channel only if it starts with \fBfoobar\fR: +.PP .CS # Save the offset in case we need to undo the read... set offset [\fBtell\fR $chan] @@ -47,9 +42,7 @@ if {[read $chan 6] eq "foobar"} { seek $chan $offset } .CE - .SH "SEE ALSO" file(n), open(n), close(n), gets(n), seek(n), Tcl_StandardChannels(3) - .SH KEYWORDS access position, channel, seeking |