QUdpSocket Class Reference

\reentrant More...

#include <qudpsocket.h>

Inheritance diagram for QUdpSocket:

Collaboration diagram for QUdpSocket:

Public Member Functions
	QUdpSocket (QObject *parent=nullptr)
	Creates a QUdpSocket object.
virtual	~QUdpSocket ()
	Destroys the socket, closing the connection if necessary.
bool	joinMulticastGroup (const QHostAddress &groupAddress)
bool	joinMulticastGroup (const QHostAddress &groupAddress, const QNetworkInterface &iface)
bool	leaveMulticastGroup (const QHostAddress &groupAddress)
bool	leaveMulticastGroup (const QHostAddress &groupAddress, const QNetworkInterface &iface)
QNetworkInterface	multicastInterface () const
void	setMulticastInterface (const QNetworkInterface &iface)
bool	hasPendingDatagrams () const
	Returns true if at least one datagram is waiting to be read; otherwise returns false.
qint64	pendingDatagramSize () const
	Returns the size of the first pending UDP datagram.
QNetworkDatagram	receiveDatagram (qint64 maxSize=-1)
qint64	readDatagram (char *data, qint64 maxlen, QHostAddress *host=nullptr, quint16 *port=nullptr)
	Receives a datagram no larger than maxSize bytes and stores it in data.
qint64	writeDatagram (const QNetworkDatagram &datagram)
qint64	writeDatagram (const char *data, qint64 len, const QHostAddress &host, quint16 port)
	Sends the datagram at data of size size to the host address address at port port.
qint64	writeDatagram (const QByteArray &datagram, const QHostAddress &host, quint16 port)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Sends the datagram datagram to the host address host and at port port.
Public Member Functions inherited from QAbstractSocket
	QAbstractSocket (SocketType socketType, QObject *parent)
	Creates a new abstract socket of type socketType.
virtual	~QAbstractSocket ()
	Destroys the socket.
virtual void	resume ()
PauseModes	pauseMode () const
void	setPauseMode (PauseModes pauseMode)
virtual bool	bind (const QHostAddress &address, quint16 port=0, BindMode mode=DefaultForPlatform)
bool	bind (QHostAddress::SpecialAddress addr, quint16 port=0, BindMode mode=DefaultForPlatform)
bool	bind (quint16 port=0, BindMode mode=DefaultForPlatform)
virtual void	connectToHost (const QString &hostName, quint16 port, OpenMode mode=ReadWrite, NetworkLayerProtocol protocol=AnyIPProtocol)
	Attempts to make a connection to hostName on the given port.
void	connectToHost (const QHostAddress &address, quint16 port, OpenMode mode=ReadWrite)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Attempts to make a connection to address on port port.
virtual void	disconnectFromHost ()
	Attempts to close the socket.
bool	isValid () const
	Returns true if the socket is valid and ready for use; otherwise returns false.
qint64	bytesAvailable () const override
	Returns the number of incoming bytes that are waiting to be read.
qint64	bytesToWrite () const override
	Returns the number of bytes that are waiting to be written.
quint16	localPort () const
	Returns the host port number (in native byte order) of the local socket if available; otherwise returns 0.
QHostAddress	localAddress () const
	Returns the host address of the local socket if available; otherwise returns QHostAddress::Null.
quint16	peerPort () const
	Returns the port of the connected peer if the socket is in ConnectedState; otherwise returns 0.
QHostAddress	peerAddress () const
	Returns the address of the connected peer if the socket is in ConnectedState; otherwise returns QHostAddress::Null.
QString	peerName () const
	Returns the name of the peer as specified by connectToHost(), or an empty QString if connectToHost() has not been called.
qint64	readBufferSize () const
	Returns the size of the internal read buffer.
virtual void	setReadBufferSize (qint64 size)
	Sets the size of QAbstractSocket's internal read buffer to be size bytes.
void	abort ()
	Aborts the current connection and resets the socket.
virtual qintptr	socketDescriptor () const
	Returns the native socket descriptor of the QAbstractSocket object if this is available; otherwise returns -1.
virtual bool	setSocketDescriptor (qintptr socketDescriptor, SocketState state=ConnectedState, OpenMode openMode=ReadWrite)
	Initializes QAbstractSocket with the native socket descriptor socketDescriptor.
virtual void	setSocketOption (QAbstractSocket::SocketOption option, const QVariant &value)
virtual QVariant	socketOption (QAbstractSocket::SocketOption option)
SocketType	socketType () const
	Returns the socket type (TCP, UDP, or other).
SocketState	state () const
	Returns the state of the socket.
SocketError	error () const
	Returns the type of error that last occurred.
void	close () override
	Closes the I/O device for the socket and calls disconnectFromHost() to close the socket's connection.
bool	isSequential () const override
	\reimp
bool	flush ()
	This function writes as much as possible from the internal write buffer to the underlying network socket, without blocking.
virtual bool	waitForConnected (int msecs=30000)
	Waits until the socket is connected, up to msecs milliseconds.
bool	waitForReadyRead (int msecs=30000) override
	This function blocks until new data is available for reading and the \l{QIODevice::}{readyRead()} signal has been emitted.
bool	waitForBytesWritten (int msecs=30000) override
	\reimp
virtual bool	waitForDisconnected (int msecs=30000)
	Waits until the socket has disconnected, up to msecs milliseconds.
void	setProxy (const QNetworkProxy &networkProxy)
QNetworkProxy	proxy () const
QString	protocolTag () const
void	setProtocolTag (const QString &tag)
Public Member Functions inherited from QIODevice
	QIODevice ()
	Constructs a QIODevice object.
	QIODevice (QObject *parent)
	Constructs a QIODevice object with the given parent.
virtual	~QIODevice ()
	The destructor is virtual, and QIODevice is an abstract base class.
QIODeviceBase::OpenMode	openMode () const
	Returns the mode in which the device has been opened; i.e.
void	setTextModeEnabled (bool enabled)
	If enabled is true, this function sets the \l Text flag on the device; otherwise the \l Text flag is removed.
bool	isTextModeEnabled () const
	Returns true if the \l Text flag is enabled; otherwise returns false.
bool	isOpen () const
	Returns true if the device is open; otherwise returns false.
bool	isReadable () const
	Returns true if data can be read from the device; otherwise returns false.
bool	isWritable () const
	Returns true if data can be written to the device; otherwise returns false.
virtual bool	isSequential () const
	Returns true if this device is sequential; otherwise returns false.
int	readChannelCount () const
int	writeChannelCount () const
int	currentReadChannel () const
void	setCurrentReadChannel (int channel)
int	currentWriteChannel () const
void	setCurrentWriteChannel (int channel)
virtual bool	open (QIODeviceBase::OpenMode mode)
	Opens the device and sets its OpenMode to mode.
virtual void	close ()
	First emits aboutToClose(), then closes the device and sets its OpenMode to NotOpen.
virtual qint64	pos () const
	For random-access devices, this function returns the position that data is written to or read from.
virtual qint64	size () const
	For open random-access devices, this function returns the size of the device.
virtual bool	seek (qint64 pos)
	For random-access devices, this function sets the current position to pos, returning true on success, or false if an error occurred.
virtual bool	atEnd () const
	Returns true if the current read and write position is at the end of the device (i.e.
virtual bool	reset ()
	Seeks to the start of input for random-access devices.
virtual qint64	bytesAvailable () const
	Returns the number of bytes that are available for reading.
virtual qint64	bytesToWrite () const
	For buffered devices, this function returns the number of bytes waiting to be written.
qint64	read (char *data, qint64 maxlen)
	Reads at most maxSize bytes from the device into data, and returns the number of bytes read.
QByteArray	read (qint64 maxlen)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Reads at most maxSize bytes from the device, and returns the data read as a QByteArray.
QByteArray	readAll ()
	Reads all remaining data from the device, and returns it as a byte array.
qint64	readLine (char *data, qint64 maxlen)
	This function reads a line of ASCII characters from the device, up to a maximum of maxSize - 1 bytes, stores the characters in data, and returns the number of bytes read.
QByteArray	readLine (qint64 maxlen=0)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Reads a line from the device, but no more than maxSize characters, and returns the result as a byte array.
virtual bool	canReadLine () const
	Returns true if a complete line of data can be read from the device; otherwise returns false.
void	startTransaction ()
void	commitTransaction ()
void	rollbackTransaction ()
bool	isTransactionStarted () const
qint64	write (const char *data, qint64 len)
	Writes at most maxSize bytes of data from data to the device.
qint64	write (const char *data)
qint64	write (const QByteArray &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Writes the content of data to the device.
qint64	peek (char *data, qint64 maxlen)
QByteArray	peek (qint64 maxlen)
qint64	skip (qint64 maxSize)
virtual bool	waitForReadyRead (int msecs)
	Blocks until new data is available for reading and the readyRead() signal has been emitted, or until msecs milliseconds have passed.
virtual bool	waitForBytesWritten (int msecs)
	For buffered devices, this function waits until a payload of buffered written data has been written to the device and the bytesWritten() signal has been emitted, or until msecs milliseconds have passed.
void	ungetChar (char c)
	Puts the character c back into the device, and decrements the current position unless the position is 0.
bool	putChar (char c)
	Writes the character c to the device.
bool	getChar (char *c)
	Reads one character from the device and stores it in c.
QString	errorString () const
	Returns a human-readable description of the last device error that occurred.
Public Member Functions inherited from QObject
Q_INVOKABLE	QObject (QObject *parent=nullptr)
	Constructs an object with parent object parent.
virtual	~QObject ()
	Destroys the object, deleting all its child objects.
virtual bool	event (QEvent *event)
	This virtual function receives events to an object and should return true if the event e was recognized and processed.
virtual bool	eventFilter (QObject *watched, QEvent *event)
	Filters events if this object has been installed as an event filter for the watched object.
QString	objectName () const
Q_WEAK_OVERLOAD void	setObjectName (const QString &name)
	Sets the object's name to name.
void	setObjectName (QAnyStringView name)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
QBindable< QString >	bindableObjectName ()
bool	isWidgetType () const
	Returns true if the object is a widget; otherwise returns false.
bool	isWindowType () const
	Returns true if the object is a window; otherwise returns false.
bool	isQuickItemType () const
	Returns true if the object is a QQuickItem; otherwise returns false.
bool	signalsBlocked () const noexcept
	Returns true if signals are blocked; otherwise returns false.
bool	blockSignals (bool b) noexcept
	If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it).
QThread *	thread () const
	Returns the thread in which the object lives.
void	moveToThread (QThread *thread)
	Changes the thread affinity for this object and its children.
int	startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)
	This is an overloaded function that will start a timer of type timerType and a timeout of interval milliseconds.
int	startTimer (std::chrono::milliseconds time, Qt::TimerType timerType=Qt::CoarseTimer)
void	killTimer (int id)
	Kills the timer with timer identifier, id.
template<typename T >
T	findChild (const QString &aName=QString(), Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	Returns the child of this object that can be cast into type T and that is called name, or \nullptr if there is no such object.
template<typename T >
QList< T >	findChildren (const QString &aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) 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.
template<typename T >
QList< T >	findChildren (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
const QObjectList &	children () const
	Returns a list of child objects.
void	setParent (QObject *parent)
	Makes the object a child of parent.
void	installEventFilter (QObject *filterObj)
	Installs an event filter filterObj on this object.
void	removeEventFilter (QObject *obj)
	Removes an event filter object obj from this object.
QMetaObject::Connection	connect (const QObject *sender, const char *signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const
bool	disconnect (const char *signal=nullptr, const QObject *receiver=nullptr, const char *member=nullptr) const
bool	disconnect (const QObject *receiver, const char *member=nullptr) const
void	dumpObjectTree () const
	Dumps a tree of children to the debug output.
void	dumpObjectInfo () const
	Dumps information about signal connections, etc.
bool	setProperty (const char *name, const QVariant &value)
	Sets the value of the object's name property to value.
bool	setProperty (const char *name, QVariant &&value)
QVariant	property (const char *name) const
	Returns the value of the object's name property.
QList< QByteArray >	dynamicPropertyNames () const
QBindingStorage *	bindingStorage ()
const QBindingStorage *	bindingStorage () const
QObject *	parent () const
	Returns a pointer to the parent object.
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.

Additional Inherited Members
Public Types inherited from QAbstractSocket
enum	SocketType { TcpSocket , UdpSocket , SctpSocket , UnknownSocketType = -1 }
	This enum describes the transport layer protocol. More...
enum	SocketError {   ConnectionRefusedError , RemoteHostClosedError , HostNotFoundError , SocketAccessError ,   SocketResourceError , SocketTimeoutError , DatagramTooLargeError , NetworkError ,   AddressInUseError , SocketAddressNotAvailableError , UnsupportedSocketOperationError , UnfinishedSocketOperationError ,   ProxyAuthenticationRequiredError , SslHandshakeFailedError , ProxyConnectionRefusedError , ProxyConnectionClosedError ,   ProxyConnectionTimeoutError , ProxyNotFoundError , ProxyProtocolError , OperationError ,   SslInternalError , SslInvalidUserDataError , TemporaryError , UnknownSocketError = -1 }
	This enum describes the socket errors that can occur. More...
enum	SocketState {   UnconnectedState , HostLookupState , ConnectingState , ConnectedState ,   BoundState , ListeningState , ClosingState }
	This enum describes the different states in which a socket can be. More...
enum	SocketOption {   LowDelayOption , KeepAliveOption , MulticastTtlOption , MulticastLoopbackOption ,   TypeOfServiceOption , SendBufferSizeSocketOption , ReceiveBufferSizeSocketOption , PathMtuSocketOption }
enum	BindFlag { DefaultForPlatform = 0x0 , ShareAddress = 0x1 , DontShareAddress = 0x2 , ReuseAddressHint = 0x4 }
enum	PauseMode { PauseNever = 0x0 , PauseOnSslErrors = 0x1 }
using	NetworkLayerProtocol = QHostAddress::NetworkLayerProtocol
Public Types inherited from QIODeviceBase
enum	OpenModeFlag {   NotOpen = 0x0000 , ReadOnly = 0x0001 , WriteOnly = 0x0002 , ReadWrite = ReadOnly | WriteOnly ,   Append = 0x0004 , Truncate = 0x0008 , Text = 0x0010 , Unbuffered = 0x0020 ,   NewOnly = 0x0040 , ExistingOnly = 0x0080 }
	This enum is used with QIODevice::open() to describe the mode in which a device is opened. More...
Public Slots inherited from QObject
void	deleteLater ()
	\threadsafe
Signals inherited from QAbstractSocket
void	hostFound ()
	This signal is emitted after connectToHost() has been called and the host lookup has succeeded.
void	connected ()
	This signal is emitted after connectToHost() has been called and a connection has been successfully established.
void	disconnected ()
	This signal is emitted when the socket has been disconnected.
void	stateChanged (QAbstractSocket::SocketState)
	This signal is emitted whenever QAbstractSocket's state changes.
void	errorOccurred (QAbstractSocket::SocketError)
void	proxyAuthenticationRequired (const QNetworkProxy &proxy, QAuthenticator *authenticator)
Signals inherited from QIODevice
void	readyRead ()
	This signal is emitted once every time new data is available for reading from the device's current read channel.
void	channelReadyRead (int channel)
void	bytesWritten (qint64 bytes)
	This signal is emitted every time a payload of data has been written to the device's current write channel.
void	channelBytesWritten (int channel, qint64 bytes)
void	aboutToClose ()
	This signal is emitted when the device is about to close.
void	readChannelFinished ()
Signals inherited from QObject
void	destroyed (QObject *=nullptr)
	This signal is emitted immediately before the object obj is destroyed, after any instances of QPointer have been notified, and cannot be blocked.
void	objectNameChanged (const QString &objectName, QPrivateSignal)
	This signal is emitted after the object's name has been changed.
Static Public Member Functions inherited from QObject
static QMetaObject::Connection	connect (const QObject *sender, const char *signal, const QObject *receiver, const char *member, Qt::ConnectionType=Qt::AutoConnection)
	\threadsafe
static QMetaObject::Connection	connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)
template<typename Func1 , typename Func2 >
static QMetaObject::Connection	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const typename QtPrivate::ContextTypeForFunctor< Func2 >::ContextType *context, Func2 &&slot, Qt::ConnectionType type=Qt::AutoConnection)
template<typename Func1 , typename Func2 >
static QMetaObject::Connection	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 &&slot)
static bool	disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *member)
	\threadsafe
static bool	disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &member)
static bool	disconnect (const QMetaObject::Connection &)
	Disconnect a connection.
template<typename Func1 , typename Func2 >
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const typename QtPrivate::FunctionPointer< Func2 >::Object *receiver, Func2 slot)
template<typename Func1 >
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const QObject *receiver, void **zero)
Static Public Attributes inherited from QAbstractSocket
static constexpr auto	IPv4Protocol = QHostAddress::IPv4Protocol
static constexpr auto	IPv6Protocol = QHostAddress::IPv6Protocol
static constexpr auto	AnyIPProtocol = QHostAddress::AnyIPProtocol
static constexpr auto	UnknownNetworkLayerProtocol = QHostAddress::UnknownNetworkLayerProtocol
Protected Member Functions inherited from QAbstractSocket
qint64	readData (char *data, qint64 maxlen) override
	\reimp
qint64	readLineData (char *data, qint64 maxlen) override
	\reimp
qint64	skipData (qint64 maxSize) override
	\reimp
qint64	writeData (const char *data, qint64 len) override
	\reimp
void	setSocketState (SocketState state)
	Sets the state of the socket to state.
void	setSocketError (SocketError socketError)
	Sets the type of error that last occurred to socketError.
void	setLocalPort (quint16 port)
void	setLocalAddress (const QHostAddress &address)
void	setPeerPort (quint16 port)
void	setPeerAddress (const QHostAddress &address)
void	setPeerName (const QString &name)
	QAbstractSocket (SocketType socketType, QAbstractSocketPrivate &dd, QObject *parent=nullptr)
Protected Member Functions inherited from QIODevice
	QIODevice (QIODevicePrivate &dd, QObject *parent=nullptr)
virtual qint64	readData (char *data, qint64 maxlen)=0
	Reads up to maxSize bytes from the device into data, and returns the number of bytes read or -1 if an error occurred.
virtual qint64	readLineData (char *data, qint64 maxlen)
	Reads up to maxSize characters into data and returns the number of characters read.
virtual qint64	skipData (qint64 maxSize)
virtual qint64	writeData (const char *data, qint64 len)=0
	Writes up to maxSize bytes from data to the device.
void	setOpenMode (QIODeviceBase::OpenMode openMode)
	Sets the OpenMode of the device to openMode.
void	setErrorString (const QString &errorString)
	Sets the human readable description of the last device error that occurred to str.
Protected Member Functions inherited from QObject
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 \nullptr.
int	senderSignalIndex () const
int	receivers (const char *signal) const
	Returns the number of receivers connected to the signal.
bool	isSignalConnected (const QMetaMethod &signal) const
virtual void	timerEvent (QTimerEvent *event)
	This event handler can be reimplemented in a subclass to receive timer events for the object.
virtual void	childEvent (QChildEvent *event)
	This event handler can be reimplemented in a subclass to receive child events.
virtual void	customEvent (QEvent *event)
	This event handler can be reimplemented in a subclass to receive custom events.
virtual void	connectNotify (const QMetaMethod &signal)
virtual void	disconnectNotify (const QMetaMethod &signal)
	QObject (QObjectPrivate &dd, QObject *parent=nullptr)
Protected Member Functions inherited from QIODeviceBase
	~QIODeviceBase ()=default
Protected Attributes inherited from QObject
QScopedPointer< QObjectData >	d_ptr
Properties inherited from QObject
QString	objectName
	the name of this object
Related Symbols inherited from QObject
template< class T > T	qobject_cast (const QObject *object)
	Returns the given object cast to type T if the object is of type T (or of a subclass); otherwise returns \nullptr.
template< typename T > T	qFindChildqFindChildren (const QObject *obj, const QString &name)()
template< typename T > QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()
	QObjectList
	\macro Q_CLASSINFO(Name, Value)

Detailed Description

\reentrant

The QUdpSocket class provides a UDP socket.

\inmodule QtNetwork

UDP (User Datagram Protocol) is a lightweight, unreliable, datagram-oriented, connectionless protocol. It can be used when reliability isn't important. QUdpSocket is a subclass of QAbstractSocket that allows you to send and receive UDP datagrams.

The most common way to use this class is to bind to an address and port using bind(), then call writeDatagram() and readDatagram() / receiveDatagram() to transfer data. If you want to use the standard QIODevice functions read(), readLine(), write(), etc., you must first connect the socket directly to a peer by calling connectToHost().

The socket emits the bytesWritten() signal every time a datagram is written to the network. If you just want to send datagrams, you don't need to call bind().

The readyRead() signal is emitted whenever datagrams arrive. In that case, hasPendingDatagrams() returns true. Call pendingDatagramSize() to obtain the size of the first pending datagram, and readDatagram() or receiveDatagram() to read it.

Note

An incoming datagram should be read when you receive the readyRead() signal, otherwise this signal will not be emitted for the next datagram.

Example:

void Server::initSocket()
{
    udpSocket = new QUdpSocket(this);
    udpSocket->bind(QHostAddress::LocalHost, 7755);
 
    connect(udpSocket, &QUdpSocket::readyRead,
            this, &Server::readPendingDatagrams);
}
 
void Server::readPendingDatagrams()
{
    while (udpSocket->hasPendingDatagrams()) {
        QNetworkDatagram datagram = udpSocket->receiveDatagram();
        processTheDatagram(datagram);
    }
}

QUdpSocket also supports UDP multicast. Use joinMulticastGroup() and leaveMulticastGroup() to control group membership, and QAbstractSocket::MulticastTtlOption and QAbstractSocket::MulticastLoopbackOption to set the TTL and loopback socket options. Use setMulticastInterface() to control the outgoing interface for multicast datagrams, and multicastInterface() to query it.

With QUdpSocket, you can also establish a virtual connection to a UDP server using connectToHost() and then use read() and write() to exchange datagrams without specifying the receiver for each datagram.

The \l{broadcastsender}{Broadcast Sender}, \l{broadcastreceiver}{Broadcast Receiver}, \l{multicastsender}{Multicast Sender}, and \l{multicastreceiver}{Multicast Receiver} examples illustrate how to use QUdpSocket in applications.

See also

QTcpSocket, QNetworkDatagram

Definition at line 20 of file qudpsocket.h.

Constructor & Destructor Documentation

QUdpSocket()

QUdpSocket::QUdpSocket ( QObject *  parent = nullptr )

explicit

Creates a QUdpSocket object.

parent is passed to the QObject constructor.

See also

socketType()

Definition at line 121 of file qudpsocket.cpp.

~QUdpSocket()

QUdpSocket::~QUdpSocket ( )

virtual

Destroys the socket, closing the connection if necessary.

See also

close()

Definition at line 132 of file qudpsocket.cpp.

Member Function Documentation

hasPendingDatagrams()

bool QUdpSocket::hasPendingDatagrams

(

)

const

Returns true if at least one datagram is waiting to be read; otherwise returns false.

See also

pendingDatagramSize(), readDatagram()

Definition at line 266 of file qudpsocket.cpp.

References QT_CHECK_BOUND.

Referenced by QSocks5SocketEnginePrivate::_q_udpSocketReadNotification().

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joinMulticastGroup() [1/2]

bool QUdpSocket::joinMulticastGroup

(

const QHostAddress &

groupAddress

)

Since

4.8

Joins the multicast group specified by groupAddress on the default interface chosen by the operating system. The socket must be in BoundState, otherwise an error occurs.

Note that if you are attempting to join an IPv4 group, your socket must not be bound using IPv6 (or in dual mode, using QHostAddress::Any). You must use QHostAddress::AnyIPv4 instead.

This function returns true if successful; otherwise it returns false and sets the socket error accordingly.

Note

Joining IPv6 multicast groups without an interface selection is not supported in all operating systems. Consider using the overload where the interface is specified.

See also

leaveMulticastGroup()

Definition at line 158 of file qudpsocket.cpp.

References joinMulticastGroup().

Referenced by joinMulticastGroup().

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joinMulticastGroup() [2/2]

bool QUdpSocket::joinMulticastGroup	(	const QHostAddress &	groupAddress,
		const QNetworkInterface &	iface
	)

Since

4.8 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Joins the multicast group address groupAddress on the interface iface.

See also

leaveMulticastGroup()

Definition at line 172 of file qudpsocket.cpp.

References d, and QT_CHECK_BOUND.

leaveMulticastGroup() [1/2]

bool QUdpSocket::leaveMulticastGroup

(

const QHostAddress &

groupAddress

)

Since

4.8

Leaves the multicast group specified by groupAddress on the default interface chosen by the operating system. The socket must be in BoundState, otherwise an error occurs.

This function returns true if successful; otherwise it returns false and sets the socket error accordingly.

Note

This function should be called with the same arguments as were passed to joinMulticastGroup().

See also

joinMulticastGroup()

Definition at line 195 of file qudpsocket.cpp.

References leaveMulticastGroup().

Referenced by leaveMulticastGroup().

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leaveMulticastGroup() [2/2]

bool QUdpSocket::leaveMulticastGroup	(	const QHostAddress &	groupAddress,
		const QNetworkInterface &	iface
	)

Since

4.8 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Leaves the multicast group specified by groupAddress on the interface iface.

Note

This function should be called with the same arguments as were passed to joinMulticastGroup().

See also

joinMulticastGroup()

Definition at line 212 of file qudpsocket.cpp.

References QT_CHECK_BOUND.

multicastInterface()

QNetworkInterface QUdpSocket::multicastInterface

(

)

const

Since

4.8

Returns the interface for the outgoing interface for multicast datagrams. This corresponds to the IP_MULTICAST_IF socket option for IPv4 sockets and the IPV6_MULTICAST_IF socket option for IPv6 sockets. If no interface has been previously set, this function returns an invalid QNetworkInterface. The socket must be in BoundState, otherwise an invalid QNetworkInterface is returned.

See also

setMulticastInterface()

Definition at line 231 of file qudpsocket.cpp.

References d, and QT_CHECK_BOUND.

pendingDatagramSize()

qint64 QUdpSocket::pendingDatagramSize

(

)

const

Returns the size of the first pending UDP datagram.

If there is no datagram available, this function returns -1.

See also

hasPendingDatagrams(), readDatagram()

Definition at line 278 of file qudpsocket.cpp.

References QT_CHECK_BOUND.

Referenced by QSocks5SocketEnginePrivate::_q_udpSocketReadNotification().

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readDatagram()

qint64 QUdpSocket::readDatagram	(	char *	data,
		qint64	maxSize,
		QHostAddress *	address = nullptr,
		quint16 *	port = nullptr
	)

Receives a datagram no larger than maxSize bytes and stores it in data.

The sender's host address and port is stored in address and *port (unless the pointers are \nullptr).

Returns the size of the datagram on success; otherwise returns -1.

If maxSize is too small, the rest of the datagram will be lost. To avoid loss of data, call pendingDatagramSize() to determine the size of the pending datagram before attempting to read it. If maxSize is 0, the datagram will be discarded.

See also

writeDatagram(), hasPendingDatagrams(), pendingDatagramSize()

Definition at line 458 of file qudpsocket.cpp.

References d, header(), qDebug, QT_CHECK_BOUND, QAbstractSocket::TemporaryError, tr, and QAbstractSocketEngine::WantDatagramSender.

Referenced by QSocks5SocketEnginePrivate::_q_udpSocketReadNotification().

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receiveDatagram()

QNetworkDatagram QUdpSocket::receiveDatagram

(

qint64

maxSize = -1

)

Since

5.8

Receives a datagram no larger than maxSize bytes and returns it in the QNetworkDatagram object, along with the sender's host address and port. If possible, this function will also try to determine the datagram's destination address, port, and the number of hop counts at reception time.

On failure, returns a QNetworkDatagram that reports \l {QNetworkDatagram::isValid()}{not valid}.

If maxSize is too small, the rest of the datagram will be lost. If maxSize is 0, the datagram will be discarded. If maxSize is -1 (the default), this function will attempt to read the entire datagram.

See also

writeDatagram(), hasPendingDatagrams(), pendingDatagramSize()

Definition at line 415 of file qudpsocket.cpp.

References d, qDebug, QT_CHECK_BOUND, Qt::Uninitialized, and QAbstractSocketEngine::WantAll.

setMulticastInterface()

void QUdpSocket::setMulticastInterface

(

const QNetworkInterface &

iface

)

Since

4.8

Sets the outgoing interface for multicast datagrams to the interface iface. This corresponds to the IP_MULTICAST_IF socket option for IPv4 sockets and the IPV6_MULTICAST_IF socket option for IPv6 sockets. The socket must be in BoundState, otherwise this function does nothing.

See also

multicastInterface(), joinMulticastGroup(), leaveMulticastGroup()

Definition at line 248 of file qudpsocket.cpp.

References d, QAbstractSocket::isValid(), and qWarning.

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writeDatagram() [1/3]

qint64 QUdpSocket::writeDatagram	(	const char *	data,
		qint64	size,
		const QHostAddress &	address,
		quint16	port
	)

Sends the datagram at data of size size to the host address address at port port.

Returns the number of bytes sent on success; otherwise returns -1.

Datagrams are always written as one block. The maximum size of a datagram is highly platform-dependent, but can be as low as 8192 bytes. If the datagram is too large, this function will return -1 and error() will return DatagramTooLargeError.

Sending datagrams larger than 512 bytes is in general disadvised, as even if they are sent successfully, they are likely to be fragmented by the IP layer before arriving at their final destination.

Warning

Calling this function on a connected UDP socket may result in an error and no packet being sent. If you are using a connected socket, use write() to send datagrams.

See also

readDatagram(), write()

Definition at line 305 of file qudpsocket.cpp.

References QHostAddress::Any, QAbstractSocket::bind(), QIODevice::bytesWritten(), d, emit, qDebug, QAbstractSocket::state(), QAbstractSocket::TemporaryError, tr, and QAbstractSocket::UnconnectedState.

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writeDatagram() [2/3]

qint64 QUdpSocket::writeDatagram ( const QByteArray &  datagram, const QHostAddress &  host, quint16  port  )

inline

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Sends the datagram datagram to the host address host and at port port.

The function returns the number of bytes sent if it succeeded or -1 if it encountered an error.

Definition at line 53 of file qudpsocket.h.

References QByteArray::constData(), QByteArray::size(), and writeDatagram().

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writeDatagram() [3/3]

qint64 QUdpSocket::writeDatagram

(

const QNetworkDatagram &

datagram

)

Since

5.8 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Sends the datagram datagram to the host address and port numbers contained in datagram, using the network interface and hop count limits also set there. If the destination address and port numbers are unset, this function will send to the address that was passed to connectToHost().

If the destination address is IPv6 with a non-empty \l{QHostAddress::scopeId()}{scope id} but differs from the interface index in datagram, it is undefined which interface the operating system will choose to send on.

The function returns the number of bytes sent if it succeeded or -1 if it encountered an error.

Warning

Calling this function on a connected UDP socket may result in an error and no packet being sent. If you are using a connected socket, use write() to send datagrams.

See also

QNetworkDatagram::setDestination(), QNetworkDatagram::setHopLimit(), QNetworkDatagram::setInterfaceIndex()

Definition at line 370 of file qudpsocket.cpp.

References QHostAddress::Any, QAbstractSocket::bind(), QIODevice::bytesWritten(), QByteArray::constData(), d, QNetworkDatagramPrivate::data, QNetworkDatagram::destinationAddress(), QNetworkDatagram::destinationPort(), emit, QNetworkDatagramPrivate::header, qDebug, QByteArray::size(), QAbstractSocket::state(), QString::toLatin1(), QHostAddress::toString(), and QAbstractSocket::UnconnectedState.

Referenced by dtlsbio::q_dgram_write().

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---

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

• qtbase/src/network/socket/qudpsocket.h
• qtbase/src/network/socket/qudpsocket.cpp