<!-- Generated from null.man by EXPAND with manpage.tmml -->
<manpage id='null' cat='cmd' title='null' version='2.2' package='memchan'>
<namesection>
<name>null</name>
<desc>Create and manipulate null channels</desc>

</namesection>



<synopsis>
<syntax>
package require <package>Tcl</package> 
package require <package>memchan</package> 
<cmd>null</cmd> 
</syntax>
</synopsis>
<section>
<title>DESCRIPTION</title>

<p>
The command described here is only available in a not-yet released
version of the package. Use the CVS to get the sources.

</p>
<dl>


<dle>
<dt><cmd>null</cmd> </dt>
<dd>

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.

</dd>
</dle>

</dl>

<p>
Memory channels created by <cmd>null</cmd> provide no additional options to
set or query.

</p>
<p>

A null channel is always writable and never readable. This means that a
writable <cmd>fileevent</cmd>-handler will fire continuously and a readable
<cmd>fileevent</cmd>-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.



</p>
</section>
<seealso>
<ref>memchan</ref>
<ref>fifo</ref>
<ref>fifo2</ref>
</seealso>
<keywords>
<keyword>null</keyword>
<keyword>in-memory channel</keyword>
<keyword>channel</keyword>
<keyword>i/o</keyword>
</keywords>

</manpage>
