posix man page for null

null(3tcl)																null(3tcl)

NAME
       null - Create and manipulate null channels

SYNOPSIS
       package require Tcl

       package require memchan

       null

DESCRIPTION
       The command described here is only available in a not-yet released version 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).  Transfer-
	      ring the generated channel between interpreters is possible 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 starvation
	      of other event sources the events raised by this channel type have a configurable delay. This option  is	set  in  milliseconds  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, fifo2, memchan, random, zero

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(3tcl)