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 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). Transferring 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)