Contents

• Public Functions
• Signals
• Static Public Members
• Protected Functions
• Detailed Description

Detailed Description

TheQLocalServer class provides a local socket based server.

This class makes it possible to accept incoming local socket connections.

Calllisten() to have the server start listening for incoming connections on a specified key. ThenewConnection() signal is then emitted each time a client connects to the server.

CallnextPendingConnection() to accept the pending connection as a connectedQLocalSocket. The function returns a pointer to aQLocalSocket that can be used for communicating with the client.

If an error occurs,serverError() returns the type of error, anderrorString() can be called to get a human readable description of what happened.

When listening for connections, the name which the server is listening on is available throughserverName().

Callingclose() makesQLocalServer stop listening for incoming connections.

AlthoughQLocalServer is designed for use with an event loop, it's possible to use it without one. In that case, you must usewaitForNewConnection(), which blocks until either a connection is available or a timeout expires.

Member Function Documentation

QLocalServer::QLocalServer(QObject * parent = 0)

Create a new local socket server with the givenparent.

See alsolisten().

QLocalServer::~QLocalServer()

Destroys theQLocalServer object. If the server is listening for connections, it is automatically closed.

Any client QLocalSockets that are still connected must either disconnect or be reparented before the server is deleted.

See alsoclose().

void QLocalServer::close()

Stop listening for incoming connections. Existing connections are not effected, but any new connections will be refused.

See alsoisListening() andlisten().

QString QLocalServer::errorString() const

Returns the human-readable message appropriate to the current error reported byserverError(). If no suitable string is available, an empty string is returned.

See alsoserverError().

QString QLocalServer::fullServerName() const

Returns the full path that the server is listening on.

Note: This is platform specific

See alsolisten() andserverName().

[virtual]bool QLocalServer::hasPendingConnections() const

Returns true if the server has a pending connection; otherwise returns false.

See alsonextPendingConnection() andsetMaxPendingConnections().

[virtual protected]void QLocalServer::incomingConnection(quintptr socketDescriptor)

This virtual function is called byQLocalServer when a new connection is available.socketDescriptor is the native socket descriptor for the accepted connection.

The base implementation creates aQLocalSocket, sets the socket descriptor and then stores theQLocalSocket in an internal list of pending connections. FinallynewConnection() is emitted.

Reimplement this function to alter the server's behavior when a connection is available.

See alsonewConnection(),nextPendingConnection(), andQLocalSocket::setSocketDescriptor().

bool QLocalServer::isListening() const

Returns true if the server is listening for incoming connections otherwise false.

See alsolisten() andclose().

bool QLocalServer::listen(constQString & name)

Tells the server to listen for incoming connections onname. If the server is currently listening then it will return false. Return true on success otherwise false.

name can be a single name andQLocalServer will determine the correct platform specific path.serverName() will return the name that is passed into listen.

Usually you would just pass in a name like "foo", but on Unix this could also be a path such as "/tmp/foo" and on Windows this could be a pipe path such as "\\.\pipe\foo"

Note: On Unix if the server crashes without closing listen will fail with AddressInUseError. To create a new server the file should be removed. On Windows two local servers can listen to the same pipe at the same time, but any connections will go to one of the server.

See alsoserverName(),isListening(), andclose().

int QLocalServer::maxPendingConnections() const

Returns the maximum number of pending accepted connections. The default is 30.

See alsosetMaxPendingConnections() andhasPendingConnections().

[signal]void QLocalServer::newConnection()

This signal is emitted every time a new connection is available.

See alsohasPendingConnections() andnextPendingConnection().

[virtual]QLocalSocket * QLocalServer::nextPendingConnection()

Returns the next pending connection as a connectedQLocalSocket object.

The socket is created as a child of the server, which means that it is automatically deleted when theQLocalServer object is destroyed. It is still a good idea to delete the object explicitly when you are done with it, to avoid wasting memory.

0 is returned if this function is called when there are no pending connections.

See alsohasPendingConnections(),newConnection(), andincomingConnection().

[static]bool QLocalServer::removeServer(constQString & name)

Removes any server instance that might cause a call tolisten() to fail and returns true if successful; otherwise returns false. This function is meant to recover from a crash, when the previous server instance has not been cleaned up.

On Windows, this function does nothing; on Unix, it removes the socket file given byname.

Warning: Be careful to avoid removing sockets of running instances.

This function was introduced in Qt 4.5.

QAbstractSocket::SocketError QLocalServer::serverError() const

Returns the type of error that occurred last or NoError.

See alsoerrorString().

QString QLocalServer::serverName() const

Returns the server name if the server is listening for connections; otherwise returns QString()

See alsolisten() andfullServerName().

void QLocalServer::setMaxPendingConnections(int numConnections)

Sets the maximum number of pending accepted connections tonumConnections.QLocalServer will accept no more thannumConnections incoming connections beforenextPendingConnection() is called.

Note: Even thoughQLocalServer will stop accepting new connections after it has reached its maximum number of pending connections, the operating system may still keep them in queue which will result in clients signaling that it is connected.

See alsomaxPendingConnections() andhasPendingConnections().

bool QLocalServer::waitForNewConnection(int msec = 0,bool * timedOut = 0)

Waits for at mostmsec milliseconds or until an incoming connection is available. Returns true if a connection is available; otherwise returns false. If the operation timed out andtimedOut is not 0, *timedOut will be set to true.

This is a blocking function call. Its use is ill-advised in a single-threaded GUI application, since the whole application will stop responding until the function returns. waitForNewConnection() is mostly useful when there is no event loop available.

The non-blocking alternative is to connect to thenewConnection() signal.

If msec is -1, this function will not time out.

See alsohasPendingConnections() andnextPendingConnection().