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authordkf <donal.k.fellows@manchester.ac.uk>2009-01-30 11:34:36 (GMT)
committerdkf <donal.k.fellows@manchester.ac.uk>2009-01-30 11:34:36 (GMT)
commit55ce0570bc00c311fdea8fa220088ba1cf56cad9 (patch)
tree426fec42bec44535ba82f29a16bdc4fa755edcc9 /doc
parentb52edeeca3ae9b5a5c62fbe5d718f7c8035232a3 (diff)
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Added another example. [Bug 1216074]
Diffstat (limited to 'doc')
-rw-r--r--doc/chan.n42
1 files changed, 40 insertions, 2 deletions
diff --git a/doc/chan.n b/doc/chan.n
index d79c717..2924465 100644
--- a/doc/chan.n
+++ b/doc/chan.n
@@ -4,7 +4,7 @@
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
-'\" RCS: @(#) $Id: chan.n,v 1.22 2008/10/15 10:43:37 dkf Exp $
+'\" RCS: @(#) $Id: chan.n,v 1.23 2009/01/30 11:34:36 dkf Exp $
.so man.macros
.TH chan n 8.5 Tcl "Tcl Built-In Commands"
.BS
@@ -733,7 +733,8 @@ named \fIchannelId\fR to be \fIlength\fR (or to the current byte
offset within the underlying data stream if \fIlength\fR is
omitted). The channel is flushed before truncation.
.
-.SH EXAMPLE
+.SH EXAMPLES
+.PP
This opens a file using a known encoding (CP1252, a very common encoding
on Windows), searches for a string, rewrites that part, and truncates the
file after a further two lines.
@@ -766,6 +767,43 @@ while {[\fBchan gets\fR $f line] >= 0} {
}
\fBchan close\fR $f
.CE
+.PP
+A network server that does echoing of its input line-by-line without
+preventing servicing of other connections at the same time.
+.PP
+.CS
+# This is a very simple logger...
+proc log {message} {
+ \fBchan puts\fR stdout $message
+}
+
+# This is called whenever a new client connects to the server
+proc connect {chan host port} {
+ set clientName [format <%s:%d> $host $port]
+ log "connection from $clientName"
+ \fBchan configure\fR $chan -blocking 0 -buffering line
+ \fBchan event\fR $chan readable [list echoLine $chan $clientName]
+}
+
+# This is called whenever either at least one byte of input
+# data is available, or the channel was closed by the client.
+proc echoLine {chan clientName} {
+ \fBchan gets\fR $chan line
+ if {[\fBchan eof\fR $chan]} {
+ log "finishing connection from $clientName"
+ \fBchan close\fR $chan
+ } elseif {![\fBchan blocked\fR $chan]} {
+ # Didn't block waiting for end-of-line
+ log "$clientName - $line"
+ \fBchan puts\fR $chan $line
+ }
+}
+
+# Create the server socket and enter the event-loop to wait
+# for incoming connections...
+socket -server connect 12345
+vwait forever
+.CE
.SH "SEE ALSO"
close(n), eof(n), fblocked(n), fconfigure(n), fcopy(n), file(n),
fileevent(n), flush(n), gets(n), open(n), puts(n), read(n), seek(n),