QCopChannel(3qt)QCopChannel(3qt)NAMEQCopChannel - Communication capabilities between several clients
SYNOPSIS
#include <qcopchannel_qws.h>
Inherits QObject.
Public Members
QCopChannel ( const QCString & channel, QObject * parent = 0, const
char * name = 0 )
virtual ~QCopChannel ()
QCString channel () const
virtual void receive ( const QCString & msg, const QByteArray & data )
Signals
void received ( const QCString & msg, const QByteArray & data )
Static Public Members
bool isRegistered ( const QCString & channel )
bool send ( const QCString & channel, const QCString & msg )
bool send ( const QCString & channel, const QCString & msg, const
QByteArray & data )
DESCRIPTION
The QCopChannel class provides communication capabilities between
several clients.
The Qt Cop (QCOP) is a COmmunication Protocol, allowing clients to
communicate both within the same address space and between different
processes.
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.
QCopChannel provides send() and isRegistered() which are static
functions usable without an object.
The channel() function returns the name of the channel.
In order to listen to the traffic on a channel, you should either
subclass QCopChannel and reimplement receive(), or connect() to the
received() signal.
MEMBER FUNCTION DOCUMENTATIONQCopChannel::QCopChannel ( const QCString & channel, QObject * parent = 0,
const char * name = 0 )
Constructs a QCop channel and registers it with the server using the
name channel. The standard parent and name arguments are passed on to
the QObject constructor.
QCopChannel::~QCopChannel () [virtual]
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.
QCString QCopChannel::channel () const
Returns the name of the channel.
bool QCopChannel::isRegistered ( const QCString & channel ) [static]
Queries the server for the existence of channel.
Returns TRUE if channel is registered; otherwise returns FALSE.
void QCopChannel::receive ( const QCString & msg, const QByteArray & data )
[virtual]
This virtual function allows subclasses of QCopChannel to process data
received from their channel.
The default implementation emits the received() signal.
Note that the format of data has to be well defined in order to extract
the information it contains.
Example:
void MyClass::receive( const QCString &msg, const QByteArray &data )
{
QDataStream stream( data, IO_ReadOnly );
if ( msg == "execute(QString,QString)" ) {
QString cmd, arg;
stream >> cmd >> arg;
...
} else if ( msg == "delete(QString)" ) {
QString filenname;
stream >> filename;
...
} else ...
}
This example assumes that the msg is a DCOP-style function signature
and the data contains the function's arguments. (See send().)
Using the DCOP convention is a recommendation, but not a requirement.
Whatever convention you use the sender and receiver must agree on the
argument types.
See also send().
void QCopChannel::received ( const QCString & msg, const QByteArray & data )
[signal]
This signal is emitted with the msg and data whenever the receive()
function gets incoming data.
bool QCopChannel::send ( const QCString & channel, const QCString & msg, const
QByteArray & data ) [static]
Send the message msg on channel channel with data data. The message
will be distributed to all clients subscribed to the channel.
Note that QDataStream provides a convenient way to fill the byte array
with auxiliary data.
Example:
QByteArray ba;
QDataStream stream( ba, IO_WriteOnly );
stream << QString("cat") << QString("file.txt");
QCopChannel::send( "System/Shell", "execute(QString,QString)", ba );
Here the channel is "System/Shell". The msg 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
"&".
Using the DCOP convention is a recommendation, but not a requirement.
Whatever convention you use the sender and receiver must agree on the
argument types.
See also receive().
bool QCopChannel::send ( const QCString & channel, const QCString & msg )
[static]
This is an overloaded member function, provided for convenience. It
behaves essentially like the above function.
Send the message msg on channel channel. The message will be
distributed to all clients subscribed to the channel.
See also receive().
SEE ALSO
http://doc.trolltech.com/qcopchannel.html
http://www.trolltech.com/faq/tech.html
COPYRIGHT
Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com. See the
license file included in the distribution for a complete license
statement.
AUTHOR
Generated automatically from the source code.
BUGS
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(qcopchannel.3qt) and the Qt version (3.3.8).
Trolltech AS 2 February 2007 QCopChannel(3qt)