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<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>QCopChannel Class Reference</h1>
<p>The QCopChannel class provides communication capabilities between
several clients.
<a href="#details">More...</a>
<p><tt>#include <<a href="qcopchannel_qws-h.html">qcopchannel_qws.h</a>></tt>
<p>Inherits <a href="qobject.html">QObject</a>.
<p><a href="qcopchannel-members.html">List of all member functions.</a>
<h2>Public Members</h2>
<ul>
<li><div class=fn><a href="#QCopChannel"><b>QCopChannel</b></a> ( const QCString & channel, QObject * parent = 0, const char * name = 0 )</div></li>
<li><div class=fn>virtual <a href="#~QCopChannel"><b>~QCopChannel</b></a> ()</div></li>
<li><div class=fn>QCString <a href="#channel"><b>channel</b></a> () const</div></li>
<li><div class=fn>virtual void <a href="#receive"><b>receive</b></a> ( const QCString & msg, const QByteArray & data )</div></li>
</ul>
<h2>Signals</h2>
<ul>
<li><div class=fn>void <a href="#received"><b>received</b></a> ( const QCString & msg, const QByteArray & data )</div></li>
</ul>
<h2>Static Public Members</h2>
<ul>
<li><div class=fn>bool <a href="#isRegistered"><b>isRegistered</b></a> ( const QCString & channel )</div></li>
<li><div class=fn>bool <a href="#send-2"><b>send</b></a> ( const QCString & channel, const QCString & msg )</div></li>
<li><div class=fn>bool <a href="#send"><b>send</b></a> ( const QCString & channel, const QCString & msg, const QByteArray & data )</div></li>
</ul>
<hr><a name="details"></a><h2>Detailed Description</h2>
<p> The QCopChannel class provides communication capabilities between
several clients.
<p> The Qt Cop (QCOP) is a COmmunication Protocol, allowing clients to
communicate both within the same address space and between different
processes.
<p> Currently, this facility is only available on Qt/Embedded. On X11
and Windows we are exploring the use of existing standards such as
DCOP and COM.
<p> QCopChannel provides <a href="#send">send</a>() and <a href="#isRegistered">isRegistered</a>() which are static
functions that are usable without an object.
<p> The <a href="#channel">channel</a>() function returns the name of the channel.
<p> In order to <em>listen</em> to the traffic on a channel, you should either
subclass QCopChannel and reimplement <a href="#receive">receive</a>(), or <a href="qobject.html#connect">connect</a>() to the
<a href="#received">received</a>() signal.
<p>
<hr><h2>Member Function Documentation</h2>
<h3 class=fn><a name="QCopChannel"></a>QCopChannel::QCopChannel ( const <a href="qcstring.html">QCString</a> & channel, <a href="qobject.html">QObject</a> * parent = 0, const char * name = 0 )
</h3>
Constructs a QCop channel and registers it with the server using the name
<em>channel</em>. The standard <em>parent</em> and <em>name</em> arguments are passed on
to the <a href="qobject.html">QObject</a> constructor.
<h3 class=fn><a name="~QCopChannel"></a>QCopChannel::~QCopChannel ()<tt> [virtual]</tt>
</h3>
Destroys the client's end of the channel and notifies the server
that the client has closed its connection. The server will keep the
channel open until the last registered client detaches.
<h3 class=fn><a href="qcstring.html">QCString</a> <a name="channel"></a>QCopChannel::channel () const
</h3>
Returns the name of the channel.
<h3 class=fn>bool <a name="isRegistered"></a>QCopChannel::isRegistered ( const <a href="qcstring.html">QCString</a> & channel )<tt> [static]</tt>
</h3>
Queries the server for the existence of <em>channel</em>.
<p> Returns TRUE if <em>channel</em> is registered.
<h3 class=fn>void <a name="receive"></a>QCopChannel::receive ( const <a href="qcstring.html">QCString</a> & msg, const <a href="qbytearray.html">QByteArray</a> & data )<tt> [virtual]</tt>
</h3>
This virtual function allows subclasses of QCopChannel to
process data received from their channel.
<p> The default implementation emits the <a href="#received">received</a>() signal.
<p> Note that the format of <em>data</em> has to be well defined in order to
extract the information it contains.
<p> Example:
<pre>
void MyClass::receive( const <a href="qcstring.html">QCString</a> &msg, const <a href="qbytearray.html">QByteArray</a> &data )
{
<a href="qdatastream.html">QDataStream</a> stream( data, <a href="qfile.html#open">IO_ReadOnly</a> );
if ( msg == "execute(QString,QString)" ) {
<a href="qstring.html">QString</a> cmd, arg;
stream >> cmd >> arg;
...
} else if ( msg == "delete(QString)" ) {
<a href="qstring.html">QString</a> filenname;
stream >> filename;
...
} else ...
}
</pre>
This example assumes that the <em>msg</em> is a DCOP-style function
signature and the <em>data</em> contains the function's arguments. (See
<a href="#send">send</a>().)
<p> Using the DCOP convention is a recommendation, but not a
requirement. Whatever convention you use the sender and receiver
<em>must</em> agree on the argument types.
<p> <p>See also <a href="#send">send</a>().
<h3 class=fn>void <a name="received"></a>QCopChannel::received ( const <a href="qcstring.html">QCString</a> & msg, const <a href="qbytearray.html">QByteArray</a> & data )<tt> [signal]</tt>
</h3>
<p> This signal is emitted with the <em>msg</em> and <em>data</em> whenever the
<a href="#receive">receive</a>() function gets incoming data.
<h3 class=fn>bool <a name="send"></a>QCopChannel::send ( const <a href="qcstring.html">QCString</a> & channel, const <a href="qcstring.html">QCString</a> & msg, const <a href="qbytearray.html">QByteArray</a> & data )<tt> [static]</tt>
</h3>
Send the message <em>msg</em> on channel <em>channel</em> with data <em>data</em>. The
message will be distributed to all clients subscribed to the
channel.
<p> Note that <a href="qdatastream.html">QDataStream</a> provides a convenient way to fill the byte array
with auxiliary data.
<p> Example:
<pre>
<a href="qbytearray.html">QByteArray</a> ba;
<a href="qdatastream.html">QDataStream</a> stream( ba, <a href="qfile.html#open">IO_WriteOnly</a> );
stream << QString("cat") << QString("file.txt");
QCopChannel::<a href="#send">send</a>( "System/Shell", "execute(QString,QString)", ba );
</pre>
Here the channel is "System/Shell". The <em>msg</em> is an arbitrary
string, but in the example we've used the DCOP convention of passing
a function signature. Such a signature is formatted as
functionname(types) where types is a list of zero or more
comma-separated type names, with no whitespace, no consts and no
pointer or reference marks, i.e. no "*" or "&".
<p> Using the DCOP convention is a recommendation, but not a
requirement. Whatever convention you use the sender and receiver
<em>must</em> agree on the argument types.
<p> <p>See also <a href="#receive">receive</a>().
<h3 class=fn>bool <a name="send-2"></a>QCopChannel::send ( const <a href="qcstring.html">QCString</a> & channel, const <a href="qcstring.html">QCString</a> & msg )<tt> [static]</tt>
</h3>
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
<p> Send the message <em>msg</em> on channel <em>channel</em>. The message will be
distributed to all clients subscribed to the channel.
<p> <p>See also <a href="#receive">receive</a>().
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