The QLocalServer class provides a local socket based server. More...

#include <qlocalserver.h>

Inheritance diagram for QLocalServer:

Signals
void	newConnection ()
	This signal is emitted every time a new connection is available. More...

Signals inherited from QObject
void	destroyed (QObject *=0)
	This signal is emitted immediately before the object obj is destroyed, and can not be blocked. More...

Public Functions
void	close ()
	Stop listening for incoming connections. More...

QString	errorString () const
	Returns the human-readable message appropriate to the current error reported by serverError(). More...

QString	fullServerName () const
	Returns the full path that the server is listening on. More...

virtual bool	hasPendingConnections () const
	Returns true if the server has a pending connection; otherwise returns false. More...

bool	isListening () const
	Returns true if the server is listening for incoming connections otherwise false. More...

bool	listen (const QString &name)
	Tells the server to listen for incoming connections on name. More...

int	maxPendingConnections () const
	Returns the maximum number of pending accepted connections. More...

virtual QLocalSocket *	nextPendingConnection ()
	Returns the next pending connection as a connected QLocalSocket object. More...

	QLocalServer (QObject *parent=0)
	Create a new local socket server with the given parent. More...

QAbstractSocket::SocketError	serverError () const
	Returns the type of error that occurred last or NoError. More...

QString	serverName () const
	Returns the server name if the server is listening for connections; otherwise returns QString() More...

void	setMaxPendingConnections (int numConnections)
	Sets the maximum number of pending accepted connections to numConnections. More...

bool	waitForNewConnection (int msec=0, bool *timedOut=0)
	Waits for at most msec milliseconds or until an incoming connection is available. More...

	~QLocalServer ()
	Destroys the QLocalServer object. More...

Public Functions inherited from QObject
bool	blockSignals (bool b)
	If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it). More...

const QObjectList &	children () const
	Returns a list of child objects. More...

bool	connect (const QObject sender, const char signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const

bool	disconnect (const char signal=0, const QObject receiver=0, const char *member=0)

bool	disconnect (const QObject receiver, const char member=0)

void	dumpObjectInfo ()
	Dumps information about signal connections, etc. More...

void	dumpObjectTree ()
	Dumps a tree of children to the debug output. More...

QList< QByteArray >	dynamicPropertyNames () const
	Returns the names of all properties that were dynamically added to the object using setProperty(). More...

virtual bool	event (QEvent *)
	This virtual function receives events to an object and should return true if the event e was recognized and processed. More...

virtual bool	eventFilter (QObject , QEvent )
	Filters events if this object has been installed as an event filter for the watched object. More...

template<typename T >
T	findChild (const QString &aName=QString()) const
	Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. More...

template<typename T >
QList< T >	findChildren (const QString &aName=QString()) const
	Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects. More...

template<typename T >
QList< T >	findChildren (const QRegExp &re) const

bool	inherits (const char *classname) const
	Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false. More...

void	installEventFilter (QObject *)
	Installs an event filter filterObj on this object. More...

bool	isWidgetType () const
	Returns true if the object is a widget; otherwise returns false. More...

void	killTimer (int id)
	Kills the timer with timer identifier, id. More...

virtual const QMetaObject *	metaObject () const
	Returns a pointer to the meta-object of this object. More...

void	moveToThread (QThread *thread)
	Changes the thread affinity for this object and its children. More...

QString	objectName () const

QObject *	parent () const
	Returns a pointer to the parent object. More...

QVariant	property (const char *name) const
	Returns the value of the object's name property. More...

Q_INVOKABLE	QObject (QObject *parent=0)
	Constructs an object with parent object parent. More...

void	removeEventFilter (QObject *)
	Removes an event filter object obj from this object. More...

void	setObjectName (const QString &name)

void	setParent (QObject *)
	Makes the object a child of parent. More...

bool	setProperty (const char *name, const QVariant &value)
	Sets the value of the object's name property to value. More...

void	setUserData (uint id, QObjectUserData *data)

bool	signalsBlocked () const
	Returns true if signals are blocked; otherwise returns false. More...

int	startTimer (int interval)
	Starts a timer and returns a timer identifier, or returns zero if it could not start a timer. More...

QThread *	thread () const
	Returns the thread in which the object lives. More...

QObjectUserData *	userData (uint id) const

virtual	~QObject ()
	Destroys the object, deleting all its child objects. More...

Static Public Functions
static bool	removeServer (const QString &name)
	Removes any server instance that might cause a call to listen() to fail and returns true if successful; otherwise returns false. More...

Static Public Functions inherited from QObject
static bool	connect (const QObject sender, const char signal, const QObject receiver, const char member, Qt::ConnectionType=Qt::AutoConnection)
	Creates a connection of the given type from the signal in the sender object to the method in the receiver object. More...

static bool	connect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)

static bool	disconnect (const QObject sender, const char signal, const QObject receiver, const char member)
	Disconnects signal in object sender from method in object receiver. More...

static bool	disconnect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &member)

static uint	registerUserData ()

static QString	tr (const char sourceText, const char comment=0, int n=-1)

static QString	trUtf8 (const char sourceText, const char comment=0, int n=-1)

Protected Functions
virtual void	incomingConnection (quintptr socketDescriptor)
	This virtual function is called by QLocalServer when a new connection is available. More...

Protected Functions inherited from QObject
virtual void	childEvent (QChildEvent *)
	This event handler can be reimplemented in a subclass to receive child events. More...

virtual void	connectNotify (const char *signal)
	This virtual function is called when something has been connected to signal in this object. More...

virtual void	customEvent (QEvent *)
	This event handler can be reimplemented in a subclass to receive custom events. More...

virtual void	disconnectNotify (const char *signal)
	This virtual function is called when something has been disconnected from signal in this object. More...

	QObject (QObjectPrivate &dd, QObject *parent=0)

int	receivers (const char *signal) const
	Returns the number of receivers connected to the signal. More...

QObject *	sender () const
	Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns 0. More...

int	senderSignalIndex () const

virtual void	timerEvent (QTimerEvent *)
	This event handler can be reimplemented in a subclass to receive timer events for the object. More...

Additional Inherited Members
Public Slots inherited from QObject
void	deleteLater ()
	Schedules this object for deletion. More...

Static Public Variables inherited from QObject
static const QMetaObject	staticMetaObject
	This variable stores the meta-object for the class. More...

Protected Variables inherited from QObject
QScopedPointer< QObjectData >	d_ptr

Static Protected Variables inherited from QObject
static const QMetaObject	staticQtMetaObject

Related Functions inherited from QObject
T	qFindChildqFindChildren (const QObject *obj, const QString &name)()

QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()

QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QRegExp &regExp)()

T *	qobject_cast (QObject *object)

	QObjectList

void *	qt_find_obj_child (QObject parent, const char type, const QString &name)
	Returns a pointer to the object named name that inherits type and with a given parent. More...

Detailed Description

The QLocalServer class provides a local socket based server.

Since: 4.4

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

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

Call nextPendingConnection() to accept the pending connection as a connected QLocalSocket. The function returns a pointer to a QLocalSocket that can be used for communicating with the client.

If an error occurs, serverError() returns the type of error, and errorString() 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 through serverName().

Calling close() makes QLocalServer stop listening for incoming connections.

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

See also: QLocalSocket, QTcpServer

Definition at line 58 of file qlocalserver.h.

Constructors and Destructors

◆ QLocalServer()

QLocalServer::QLocalServer ( QObject * parent = 0 )

Create a new local socket server with the given parent.

See also: listen()

Definition at line 92 of file qlocalserver.cpp.

         : QObject(*new QLocalServerPrivate, parent)
 {
     Q_D(QLocalServer);
     d->init();
 }

◆ ~QLocalServer()

QLocalServer::~QLocalServer ( )

Destroys the QLocalServer 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 also: close()

Definition at line 108 of file qlocalserver.cpp.

 {
     if (isListening())
     close();
 }

Functions

◆ close()

void QLocalServer::close ( )

Stop listening for incoming connections.

Existing connections are not effected, but any new connections will be refused.

See also: isListening(), listen()

Definition at line 120 of file qlocalserver.cpp.

Referenced by ~QLocalServer().

 {
     Q_D(QLocalServer);
     if (!isListening())
         return;
     qDeleteAll(d->pendingConnections);
     d->pendingConnections.clear();
     d->closeServer();
     d->serverName.clear();
     d->fullServerName.clear();
     d->errorString.clear();
     d->error = QAbstractSocket::UnknownSocketError;
 }

◆ errorString()

QString QLocalServer::errorString ( ) const

Returns the human-readable message appropriate to the current error reported by serverError().

If no suitable string is available, an empty string is returned.

See also: serverError()

Definition at line 141 of file qlocalserver.cpp.

 {
     Q_D(const QLocalServer);
     return d->errorString;
 }

◆ fullServerName()

QString QLocalServer::fullServerName ( ) const

Returns the full path that the server is listening on.

Note: This is platform specific

See also: listen(), serverName()

Definition at line 338 of file qlocalserver.cpp.

 {
     Q_D(const QLocalServer);
     return d->fullServerName;
 }

◆ hasPendingConnections()

bool QLocalServer::hasPendingConnections ( ) const

virtual

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

See also: nextPendingConnection(), setMaxPendingConnections()

Definition at line 153 of file qlocalserver.cpp.

 {
     Q_D(const QLocalServer);
     return !(d->pendingConnections.isEmpty());
 }

◆ incomingConnection()

void QLocalServer::incomingConnection ( quintptr socketDescriptor )

protectedvirtual

This virtual function is called by QLocalServer when a new connection is available.

socketDescriptor is the native socket descriptor for the accepted connection.

The base implementation creates a QLocalSocket, sets the socket descriptor and then stores the QLocalSocket in an internal list of pending connections. Finally newConnection() is emitted.

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

See also: newConnection(), nextPendingConnection(), QLocalSocket::setSocketDescriptor()

Definition at line 174 of file qlocalserver.cpp.

 {
     Q_D(QLocalServer);
     QLocalSocket *socket = new QLocalSocket(this);
     socket->setSocketDescriptor(socketDescriptor);
     d->pendingConnections.enqueue(socket);
     emit newConnection();
 }

◆ isListening()

bool QLocalServer::isListening ( ) const

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

See also: listen(), close()

Definition at line 189 of file qlocalserver.cpp.

Referenced by close(), listen(), waitForNewConnection(), and ~QLocalServer().

 {
     Q_D(const QLocalServer);
     return !(d->serverName.isEmpty());
 }

◆ listen()

bool QLocalServer::listen ( const QString & name )

Tells the server to listen for incoming connections on name.

If the server is currently listening then it will return false. Return true on success otherwise false.

name can be a single name and QLocalServer 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 also: serverName(), isListening(), close()

Definition at line 216 of file qlocalserver.cpp.

 {
     Q_D(QLocalServer);
     if (isListening()) {
         qWarning("QLocalServer::listen() called when already listening");
         return false;
     }
 
     if (name.isEmpty()) {
         d->error = QAbstractSocket::HostNotFoundError;
         QString function = QLatin1String("QLocalServer::listen");
         d->errorString = tr("%1: Name error").arg(function);
         return false;
     }
 
     if (!d->listen(name)) {
         d->serverName.clear();
         d->fullServerName.clear();
         return false;
     }
 
     d->serverName = name;
     return true;
 }

◆ maxPendingConnections()

int QLocalServer::maxPendingConnections ( ) const

Returns the maximum number of pending accepted connections.

The default is 30.

See also: setMaxPendingConnections(), hasPendingConnections()

Definition at line 247 of file qlocalserver.cpp.

 {
     Q_D(const QLocalServer);
     return d->maxPendingConnections;
 }

◆ newConnection

void QLocalServer::newConnection ( )

signal

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

See also: hasPendingConnections(), nextPendingConnection()

Referenced by incomingConnection().

◆ nextPendingConnection()

QLocalSocket * QLocalServer::nextPendingConnection ( )

virtual

Returns the next pending connection as a connected QLocalSocket object.

The socket is created as a child of the server, which means that it is automatically deleted when the QLocalServer 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 also: hasPendingConnections(), newConnection(), incomingConnection()

Definition at line 277 of file qlocalserver.cpp.

 {
     Q_D(QLocalServer);
     if (d->pendingConnections.isEmpty())
         return 0;
     QLocalSocket *nextSocket = d->pendingConnections.dequeue();
 #ifndef QT_LOCALSOCKET_TCP
 #ifdef Q_OS_SYMBIAN
     if(!d->socketNotifier)
         return nextSocket;
 #endif
     if (d->pendingConnections.size() <= d->maxPendingConnections)
 #ifndef Q_OS_WIN
         d->socketNotifier->setEnabled(true);
 #else
         d->connectionEventNotifier->setEnabled(true);
 #endif
 #endif
     return nextSocket;
 }

◆ removeServer()

bool QLocalServer::removeServer ( const QString & name )

static

Removes any server instance that might cause a call to listen() to fail and returns true if successful; otherwise returns false.

Since: 4.5

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 by name.

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

Definition at line 314 of file qlocalserver.cpp.

 {
     return QLocalServerPrivate::removeServer(name);
 }

◆ serverError()

QAbstractSocket::SocketError QLocalServer::serverError ( ) const

Returns the type of error that occurred last or NoError.

See also: errorString()

Definition at line 349 of file qlocalserver.cpp.

 {
     Q_D(const QLocalServer);
     return d->error;
 }

◆ serverName()

QString QLocalServer::serverName ( ) const

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

See also: listen(), fullServerName()

Definition at line 325 of file qlocalserver.cpp.

 {
     Q_D(const QLocalServer);
     return d->serverName;
 }

◆ setMaxPendingConnections()

void QLocalServer::setMaxPendingConnections ( int numConnections )

Sets the maximum number of pending accepted connections to numConnections.

QLocalServer will accept no more than numConnections incoming connections before nextPendingConnection() is called.

Note: Even though QLocalServer 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 also: maxPendingConnections(), hasPendingConnections()

Definition at line 368 of file qlocalserver.cpp.

 {
     Q_D(QLocalServer);
     d->maxPendingConnections = numConnections;
 }

◆ waitForNewConnection()

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

Waits for at most msec milliseconds or until an incoming connection is available.

Returns true if a connection is available; otherwise returns false. If the operation timed out and timedOut 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 the newConnection() signal.

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

See also: hasPendingConnections(), nextPendingConnection()

Definition at line 391 of file qlocalserver.cpp.

 {
     Q_D(QLocalServer);
     if (timedOut)
         *timedOut = false;
 
     if (!isListening())
         return false;
 
     d->waitForNewConnection(msec, timedOut);
 
     return !d->pendingConnections.isEmpty();
 }

The documentation for this class was generated from the following files:

/src/network/socket/qlocalserver.h
/src/network/socket/qlocalserver.cpp

Signals

Public Functions

Static Public Functions

Protected Functions

Additional Inherited Members