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<title>Win32::Pipe - Win32 Named Pipe</title>
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<h1><a>Win32::Pipe - Win32 Named Pipe</a></h1>
<p><a name="__index__"></a></p>
<!-- INDEX BEGIN -->
<ul>
<li><a href="#name">NAME</a></li>
<li><a href="#synopsis">SYNOPSIS</a></li>
<li><a href="#description">DESCRIPTION</a></li>
<ul>
<li><a href="#general_use">General Use</a></li>
<li><a href="#benefits">Benefits</a></li>
</ul>
<li><a href="#constructor">CONSTRUCTOR</a></li>
<li><a href="#methods">METHODS</a></li>
<li><a href="#limitations">LIMITATIONS</a></li>
<li><a href="#installation_notes">INSTALLATION NOTES</a></li>
<li><a href="#author">AUTHOR</a></li>
<li><a href="#disclaimer">DISCLAIMER</a></li>
<li><a href="#copyright">COPYRIGHT</a></li>
</ul>
<!-- INDEX END -->
<hr />
<p>
</p>
<h1><a name="name">NAME</a></h1>
<p>Win32::Pipe - Win32 Named Pipe</p>
<p>
</p>
<hr />
<h1><a name="synopsis">SYNOPSIS</a></h1>
<p>To use this extension, follow these basic steps. First, you need to
'use' the pipe extension:</p>
<pre>
<span class="keyword">use</span> <span class="variable">Win32::Pipe</span><span class="operator">;</span>
</pre>
<p>Then you need to create a server side of a named pipe:</p>
<pre>
<span class="variable">$Pipe</span> <span class="operator">=</span> <span class="variable">new</span> <span class="variable">Win32::Pipe</span><span class="operator">(</span><span class="string">"My Pipe Name"</span><span class="operator">);</span>
</pre>
<p>or if you are going to connect to pipe that has already been created:</p>
<pre>
<span class="variable">$Pipe</span> <span class="operator">=</span> <span class="variable">new</span> <span class="variable">Win32::Pipe</span><span class="operator">(</span><span class="string">"\\\\server\\pipe\\My Pipe Name"</span><span class="operator">);</span>
</pre>
<pre>
NOTE: The "\\\\server\\pipe\\" is necessary when connecting
to an existing pipe! If you are accessing the same
machine you could use "\\\\.\\pipe\\" but either way
works fine.</pre>
<p>You should check to see if <code>$Pipe</code> is indeed defined otherwise there
has been an error.</p>
<p>Whichever end is the server, it must now wait for a connection...</p>
<pre>
<span class="variable">$Result</span> <span class="operator">=</span> <span class="variable">$Pipe</span><span class="operator">-></span><span class="variable">Connect</span><span class="operator">();</span>
</pre>
<pre>
NOTE: The client end does not do this! When the client creates
the pipe it has already connected!</pre>
<p>Now you can read and write data from either end of the pipe:</p>
<pre>
<span class="variable">$Data</span> <span class="operator">=</span> <span class="variable">$Pipe</span><span class="operator">-></span><span class="variable">Read</span><span class="operator">();</span>
</pre>
<pre>
<span class="variable">$Result</span> <span class="operator">=</span> <span class="variable">$Pipe</span><span class="operator">-></span><span class="variable">Write</span><span class="operator">(</span><span class="string">"Howdy! This is cool!"</span><span class="operator">);</span>
</pre>
<p>When the server is finished it must disconnect:</p>
<pre>
<span class="variable">$Pipe</span><span class="operator">-></span><span class="variable">Disconnect</span><span class="operator">();</span>
</pre>
<p>Now the server could <a href="#item_connect"><code>Connect</code></a> again (and wait for another client) or
it could destroy the named pipe...</p>
<pre>
<span class="variable">$Data</span><span class="operator">-></span><span class="variable">Close</span><span class="operator">();</span>
</pre>
<p>The client should <a href="#item_close"><code>Close</code></a> in order to properly end the session.</p>
<p>
</p>
<hr />
<h1><a name="description">DESCRIPTION</a></h1>
<p>
</p>
<h2><a name="general_use">General Use</a></h2>
<p>This extension gives Win32 Perl the ability to use Named Pipes. Why?
Well considering that Win32 Perl does not (yet) have the ability to
<a href="../../lib/Pod/perlfunc.html#item_fork"><code>fork</code></a> I could not see what good the <a href="../../lib/Pod/perlfunc.html#item_pipe"><code>pipe(X,Y)</code></a> was. Besides, where
I am as an admin I must have several perl daemons running on several
NT Servers. It dawned on me one day that if I could pipe all these
daemons' output to my workstation (across the net) then it would be
much easier to monitor. This was the impetus for an extension using
Named Pipes. I think that it is kinda cool. :)</p>
<p>
</p>
<h2><a name="benefits">Benefits</a></h2>
<p>And what are the benefits of this module?</p>
<ul>
<li>
<p>You may create as many named pipes as you want (uh, well, as many as
your resources will allow).</p>
</li>
<li>
<p>Currently there is a limit of 256 instances of a named pipe (once a
pipe is created you can have 256 client/server connections to that
name).</p>
</li>
<li>
<p>The default buffer size is 512 bytes; this can be altered by the
<a href="#item_resizebuffer"><code>ResizeBuffer</code></a> method.</p>
</li>
<li>
<p>All named pipes are byte streams. There is currently no way to alter a
pipe to be message based.</p>
</li>
<li>
<p>Other things that I cannot think of right now... :)</p>
</li>
</ul>
<p>
</p>
<hr />
<h1><a name="constructor">CONSTRUCTOR</a></h1>
<dl>
<dt><strong><a name="item_new">new ( NAME )</a></strong>
<dd>
<p>Creates a named pipe if used in server context or a connection to the
specified named pipe if used in client context. Client context is
determined by prepending $Name with "\\\\".</p>
</dd>
<dd>
<p>Returns <em>true</em> on success, <em>false</em> on failure.</p>
</dd>
</li>
</dl>
<p>
</p>
<hr />
<h1><a name="methods">METHODS</a></h1>
<dl>
<dt><strong><a name="item_buffersize">BufferSize ()</a></strong>
<dd>
<p>Returns the size of the instance of the buffer of the named pipe.</p>
</dd>
</li>
<dt><strong><a name="item_connect">Connect ()</a></strong>
<dd>
<p>Tells the named pipe to create an instance of the named pipe and wait
until a client connects. Returns <em>true</em> on success, <em>false</em> on
failure.</p>
</dd>
</li>
<dt><strong><a name="item_close">Close ()</a></strong>
<dd>
<p>Closes the named pipe.</p>
</dd>
</li>
<dt><strong><a name="item_disconnect">Disconnect ()</a></strong>
<dd>
<p>Disconnects (and destroys) the instance of the named pipe from the
client. Returns <em>true</em> on success, <em>false</em> on failure.</p>
</dd>
</li>
<dt><strong><a name="item_error">Error ()</a></strong>
<dd>
<p>Returns the last error messages pertaining to the named pipe. If used
in context to the package. Returns a list containing <code>ERROR_NUMBER</code>
and <code>ERROR_TEXT</code>.</p>
</dd>
</li>
<dt><strong><a name="item_read">Read ()</a></strong>
<dd>
<p>Reads from the named pipe. Returns data read from the pipe on success,
undef on failure.</p>
</dd>
</li>
<dt><strong><a name="item_resizebuffer">ResizeBuffer ( SIZE )</a></strong>
<dd>
<p>Sets the size of the buffer of the instance of the named pipe to
<code>SIZE</code>. Returns the size of the buffer on success, <em>false</em> on
failure.</p>
</dd>
</li>
<dt><strong><a name="item_write">Write ( DATA )</a></strong>
<dd>
<p>Writes <code>DATA</code> to the named pipe. Returns <em>true</em> on success, <em>false</em>
on failure.</p>
</dd>
</li>
</dl>
<p>
</p>
<hr />
<h1><a name="limitations">LIMITATIONS</a></h1>
<p>What known problems does this thing have?</p>
<ul>
<li>
<p>If someone is waiting on a <a href="#item_read"><code>Read</code></a> and the other end terminates then
you will wait for one <strong>REALLY</strong> long time! (If anyone has an idea on
how I can detect the termination of the other end let me know!)</p>
</li>
<li>
<p>All pipes are blocking. I am considering using threads and callbacks
into Perl to perform async IO but this may be too much for my time
stress. ;)</p>
</li>
<li>
<p>There is no security placed on these pipes.</p>
</li>
<li>
<p>This module has neither been optimized for speed nor optimized for
memory consumption. This may run into memory bloat.</p>
</li>
</ul>
<p>
</p>
<hr />
<h1><a name="installation_notes">INSTALLATION NOTES</a></h1>
<p>If you wish to use this module with a build of Perl other than
ActivePerl, you may wish to fetch the source distribution for this
module. The source is included as part of the <code>libwin32</code> bundle,
which you can find in any CPAN mirror here:</p>
<pre>
modules/by-authors/Gurusamy_Sarathy/libwin32-0.151.tar.gz</pre>
<p>The source distribution also contains a pair of sample client/server
test scripts. For the latest information on this module, consult the
following web site:</p>
<pre>
<a href="http://www.roth.net/perl">http://www.roth.net/perl</a></pre>
<p>
</p>
<hr />
<h1><a name="author">AUTHOR</a></h1>
<p>Dave Roth <<a href="mailto:rothd@roth.net">rothd@roth.net</a>></p>
<p>
</p>
<hr />
<h1><a name="disclaimer">DISCLAIMER</a></h1>
<p>I do not guarantee <strong>ANYTHING</strong> with this package. If you use it you
are doing so <strong>AT YOUR OWN RISK</strong>! I may or may not support this
depending on my time schedule.</p>
<p>
</p>
<hr />
<h1><a name="copyright">COPYRIGHT</a></h1>
<p>Copyright (c) 1996 Dave Roth. All rights reserved.
This program is free software; you can redistribute
it and/or modify it under the same terms as Perl itself.</p>
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