Provides a TCP-based server. More...

Inheritance diagram for QTcpServer:

Public Signals
void	acceptError (QAbstractSocket::SocketError socketError)

void	newConnection ()

Public Signals inherited from QObject
void	destroyed (QObject *obj=nullptr)

void	objectNameChanged (const QString &objectName)

Public Methods
	QTcpServer (QObject *parent=nullptr)

virtual	~QTcpServer ()

void	close ()

QString	errorString () const

virtual bool	hasPendingConnections () const

bool	isListening () const

bool	listen (const QHostAddress &address=QHostAddress::Any, quint16 port=0)

int	maxPendingConnections () const

virtual QTcpSocket *	nextPendingConnection ()

void	pauseAccepting ()

QNetworkProxy	proxy () const

void	resumeAccepting ()

QHostAddress	serverAddress () const

QAbstractSocket::SocketError	serverError () const

quint16	serverPort () const

void	setMaxPendingConnections (int numConnections)

void	setProxy (const QNetworkProxy &networkProxy)

bool	setSocketDescriptor (qintptr socketDescriptor)

qintptr	socketDescriptor () const

bool	waitForNewConnection (int msec=0, bool *timedOut=nullptr)

Public Methods inherited from QObject
	QObject (QObject *parent=nullptr)

	~QObject ()

bool	blockSignals (bool block)

const QList< QObject * > &	children () const

bool	connect (const QObject *sender, const QString &signalMethod, const QString &location, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

bool	connect (const QObject *sender, const QString &signalMethod, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

bool	disconnect (const QObject *receiver, const QString &slotMethod=QString ()) const

bool	disconnect (const QString &signalMethod, const QString &location, const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const

bool	disconnect (const QString &signalMethod=QString (), const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const

void	dumpObjectInfo ()

void	dumpObjectTree ()

QList< QString >	dynamicPropertyNames () const

virtual bool	event (QEvent *event)

virtual bool	eventFilter (QObject watched, QEvent event)

template<typename T >
T	findChild (const QString &childName=QString ()) const

template<class T >
QList< T >	findChildren (const QRegularExpression &regExp, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

template<class T >
QList< T >	findChildren (const QString &childName=QString (), Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

bool	inherits (const QString &className) const

void	installEventFilter (QObject *filterObj)

bool	isWidgetType () const

bool	isWindowType () const

void	killTimer (int id)

const QMetaObject *	metaObject () const

void	moveToThread (QThread *targetThread)

QString	objectName () const

QObject *	parent () const

template<class T = QVariant>
T	property (const QString &name) const

void	removeEventFilter (QObject *obj)

void	setObjectName (const QString &name)

void	setParent (QObject *parent)

bool	setProperty (const QString &name, const QVariant &value)

bool	signalsBlocked () const

int	startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)

QThread *	thread () const

Protected Methods
void	addPendingConnection (QTcpSocket *socket)

virtual void	incomingConnection (qintptr socketDescriptor)

Protected Methods inherited from QObject
virtual void	childEvent (QChildEvent *event)

virtual void	connectNotify (const QMetaMethod &signalMethod) const

virtual void	customEvent (QEvent *event)

virtual void	disconnectNotify (const QMetaMethod &signalMethod) const

bool	isSignalConnected (const QMetaMethod &signalMethod) const

int	receivers (const QString &signal) const

QObject *	sender () const

int	senderSignalIndex () const

virtual void	timerEvent (QTimerEvent *event)

Additional Inherited Members
Public Slots inherited from QObject
void	deleteLater ()

Static Public Methods inherited from QObject
static bool	connect (const QObject sender, const QMetaMethod &signalMethod, const QObject receiver, const QMetaMethod &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

static bool	connect (const QObject sender, const QString &signalMethod, const QObject receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection, const QString &location=QString ())

static bool	connect (const QObject sender, const QString &signalMethod, const QString &location, const QObject receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn >
static bool	connect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver receiver, SlotReturn (SlotClass::slotMethod)(SlotArgs...), Qt::ConnectionType type=Qt::AutoConnection)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T >
static bool	connect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, T slotLambda, Qt::ConnectionType type=Qt::AutoConnection)

static bool	disconnect (const QObject sender, const QMetaMethod &signalMethod, const QObject receiver, const QMetaMethod &slotMethod)

static bool	disconnect (const QObject sender, const QString &signalMethod, const QObject receiver, const QString &slotMethod)

static bool	disconnect (const QObject sender, const QString &signalMethod, const QString &location, const QObject receiver, const QString &slotMethod)

static bool	disconnect (const QObject sender, std::nullptr_t, const QObject receiver, std::nullptr_t)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver receiver, SlotReturn (SlotClass::slotMethod)(SlotArgs...))

template<class Sender , class SignalClass , class... SignalArgs, class Receiver >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, std::nullptr_t slotMethod=nullptr)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, T slotMethod)

static QMetaObject &	staticMetaObject ()

static QString	tr (const char text, const char comment=nullptr, std::optional< int > numArg=std::optional< int >())

Properties inherited from QObject
	objectName

Related Functions inherited from QObject
T	qobject_cast (QObject *object)

	QObjectList

Detailed Description

The QTcpServer class provides a TCP-based server. This class makes it possible to accept incoming TCP connections. You can specify the port or have QTcpServer pick one automatically. You can listen on a specific address or on all the machine's addresses.

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

Call nextPendingConnection() to accept the pending connection as a connected QTcpSocket. The function returns a pointer to a QTcpSocket in QAbstractSocket::ConnectedState that you can use 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 address and port on which the server is listening are available as serverAddress() and serverPort().

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

Although QTcpServer is mostly designed for use with an event loop, it is 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: QTcpSocket

Constructor & Destructor Documentation

QTcpServer::QTcpServer ( QObject * parent = nullptr )

explicit

Constructs a QTcpServer object using the given parent.

See also: listen(), setSocketDescriptor()

QTcpServer::~QTcpServer ( )

virtual

Destroys the QTcpServer object.

If the server is listening for connections, the socket is automatically closed. Any client QTcpSockets that are still connected must either disconnect or be reparented before the server is deleted.

See also: close()

Method Documentation

void QTcpServer::acceptError ( QAbstractSocket::SocketError socketError )

signal

This signal is emitted when accepting a new connection results in an error. The socketError parameter describes the type of error that occurred.

See also: pauseAccepting(), resumeAccepting()

void QTcpServer::addPendingConnection ( QTcpSocket * socket )

protected

This method is called by QTcpServer::incomingConnection() to add the socket to the list of pending incoming connections.

Note: Do not forget to call this member from reimplemented incomingConnection() if you do not want to break the Pending Connections mechanism.

See also: incomingConnection()

void QTcpServer::close ( )

Closes the server. The server will no longer listen for incoming connections.

See also: listen()

QString QTcpServer::errorString ( ) const

Returns a human readable description of the last error that occurred.

See also: serverError()

bool QTcpServer::hasPendingConnections ( ) const

virtual

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

See also: nextPendingConnection(), setMaxPendingConnections()

void QTcpServer::incomingConnection ( qintptr socketDescriptor )

protectedvirtual

This method is called by QTcpServer when a new connection is available. The socketDescriptor argument is the native socket descriptor for the accepted connection.

The base implementation creates a QTcpSocket, sets the socket descriptor and then stores the QTcpSocket 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.

If this server is using QNetworkProxy then the socketDescriptor may not be usable with native socket functions, and should only be used with QTcpSocket::setSocketDescriptor().

Note: If you want to handle an incoming connection as a new QTcpSocket object in another thread you have to pass the socketDescriptor to the other thread and create the QTcpSocket object there and use its setSocketDescriptor() method.

See also: newConnection(), nextPendingConnection(), addPendingConnection()

bool QTcpServer::isListening ( ) const

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

See also: listen()

bool QTcpServer::listen	(	const QHostAddress &	address = `QHostAddress::Any`,
		quint16	port = `0`
	)

Tells the server to listen for incoming connections using the given address and port. If port is 0, a port is chosen automatically. If address is QHostAddress::Any, the server will listen on all network interfaces.

Returns true on success, otherwise returns false.

See also: isListening()

int QTcpServer::maxPendingConnections ( ) const

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

See also: setMaxPendingConnections(), hasPendingConnections()

void QTcpServer::newConnection ( )

signal

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

See also: hasPendingConnections(), nextPendingConnection()

QTcpSocket * QTcpServer::nextPendingConnection ( )

virtual

Returns the next pending connection as a connected QTcpSocket object. If there are no pending connection nullptr is returned.

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

Note: The returned QTcpSocket object can not be used from another thread. If you want to use an incoming connection from another thread, you need to override incomingConnection().

See also: hasPendingConnections()

void QTcpServer::pauseAccepting ( )

Pauses accepting new connections. Queued connections will remain in queue.

See also: resumeAccepting()

QNetworkProxy QTcpServer::proxy ( ) const

Returns the network proxy for this socket. By default QNetworkProxy::DefaultProxy is used.

See also: setProxy(), QNetworkProxy

void QTcpServer::resumeAccepting ( )

Resumes accepting new connections.

See also: pauseAccepting()

QHostAddress QTcpServer::serverAddress ( ) const

Returns the server's address if the server is listening for connections, otherwise returns QHostAddress::Null.

See also: serverPort(), listen()

QAbstractSocket::SocketError QTcpServer::serverError ( ) const

Returns an error code for the last error that occurred.

See also: errorString()

quint16 QTcpServer::serverPort ( ) const

Returns the server's port if the server is listening for connections, otherwise returns 0.

See also: serverAddress(), listen()

void QTcpServer::setMaxPendingConnections ( int numConnections )

Sets the maximum number of pending accepted connections to numConnections. QTcpServer will accept no more than numConnections incoming connections before nextPendingConnection() is called. By default, the limit is 30 pending connections.

Clients may still able to connect after the server has reached its maximum number of pending connections (i.e., QTcpSocket can still emit the connected() signal). QTcpServer will stop accepting the new connections, but the operating system may still keep them in queue.

See also: maxPendingConnections(), hasPendingConnections()

void QTcpServer::setProxy ( const QNetworkProxy & networkProxy )

Sets the explicit network proxy for this socket to networkProxy. To disable the use of a proxy for this socket use the QNetworkProxy::NoProxy proxy type.

server->setProxy(QNetworkProxy::NoProxy);

See also: proxy(), QNetworkProxy

bool QTcpServer::setSocketDescriptor ( qintptr socketDescriptor )

Sets the socket descriptor this server should use when listening for incoming connections to socketDescriptor. Returns true if the socket is set successfully, otherwise returns false.

The socket is assumed to be in listening state.

See also: socketDescriptor(), isListening()

qintptr QTcpServer::socketDescriptor ( ) const

Returns the native socket descriptor the server uses to listen for incoming instructions, or -1 if the server is not listening. If the server is using QNetworkProxy, the returned descriptor may not be usable with native socket functions.

See also: setSocketDescriptor(), isListening()

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

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

This is a blocking function call. Its use is disadvised 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.

See also: hasPendingConnections(), nextPendingConnection()

Public Signals

Public Methods

Protected Methods

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Method Documentation