null - Memory channels

# null(n) 2.2 memchan "Memory channels"

## 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 absorbes 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 possible but does not make much sense.

Memory channels created by null provide no additional options to set or query.

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

memchan, fifo, fifo2

## KEYWORDS

null, in-memory channel, channel, i/o