null(n) null(n) ______________________________________________________________________________
NAME
null - Create and manipulate null channels
SYNOPSIS
package require Tcl
package require memchan
null
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DESCRIPTION
The command described here is only available in a not-yet released ver-
sion of the package. Use the CVS to get the sources.
null creates a null channel which absorbs everything written into it.
Reading from it is not possible, or rather will always return
zero bytes. These channels are essentially Tcl-specific variants
of the null device for unixoid operating systems (/dev/null).
Transfering the generated channel between interpreters is possi-
ble but does not make much sense.
OPTIONS
Memory channels created by null provide one additional option to set or
query.
-delay ?milliseconds?
A null channel is always writable and readable. This means that
all fileevent-handlers will fire continuously. To avoid starva-
tion of other event sources the events raised by this channel
type have a configurable delay. This option is set in millisec-
onds and defaults to 5.
A null channel is always writable and never readable. This means that a
writable fileevent-handler will fire continuously and a readable
fileevent-handler never at all. The exception to the latter is only the
destruction of the channel which will cause the delivery of an eof
event to a readable handler.
SEE ALSO
fifo(n), fifo2(n), memchan(n), random(n), zero(n)
KEYWORDS
channel, i/o, in-memory channel, null
COPYRIGHT
Copyright (c) 1996-2003 Andreas Kupries <andreas_kupries@users.sourceforge.net>
Memory channels 2.2 null(n)
Mac OS X 10.8 - Generated Mon Sep 10 16:00:30 CDT 2012