\inmodule QtCore More...

#include <qsocketnotifier.h>

Inheritance diagram for QSocketNotifier:

Collaboration diagram for QSocketNotifier:

Public Types
enum	Type { Read , Write , Exception }
	This enum describes the various types of events that a socket notifier can recognize. More...

Public Slots
void	setEnabled (bool)
	If enable is true, the notifier is enabled; otherwise the notifier is disabled.

Public Slots inherited from QObject
void	deleteLater ()
	\threadsafe

Signals
void	activated (QSocketDescriptor socket, QSocketNotifier::Type activationEvent, QPrivateSignal)

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.

Public Member Functions
	QSocketNotifier (Type, QObject *parent=nullptr)

	QSocketNotifier (qintptr socket, Type, QObject *parent=nullptr)
	Constructs a socket notifier with the given parent.

	~QSocketNotifier ()
	Destroys this socket notifier.

void	setSocket (qintptr socket)

qintptr	socket () const
	Returns the socket identifier assigned to this object.

Type	type () const
	Returns the socket event type specified to the constructor.

bool	isValid () const

bool	isEnabled () const
	Returns `true` if the notifier is enabled; otherwise returns `false`.

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	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.

bool	moveToThread (QThread *thread QT6_DECL_NEW_OVERLOAD_TAIL)
	Changes the thread affinity for this object and its children and returns `true` on success.

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::nanoseconds time, Qt::TimerType timerType=Qt::CoarseTimer)

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

void	killTimer (Qt::TimerId id)

template<typename T >
T	findChild (QAnyStringView aName, 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 (QAnyStringView 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 >
T	findChild (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.

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`.

Protected Member Functions
bool	event (QEvent *) override
	\reimp

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)

Additional Inherited Members
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)

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

\inmodule QtCore

The QSocketNotifier class provides support for monitoring activity on a file descriptor.

The QSocketNotifier makes it possible to integrate Qt's event loop with other event loops based on file descriptors. File descriptor action is detected in Qt's main event loop (QCoreApplication::exec()).

\target write notifiers

Once you have opened a device using a low-level (usually platform-specific) API, you can create a socket notifier to monitor the file descriptor. If the descriptor is passed to the notifier's constructor, the socket notifier is enabled by default, i.e. it emits the activated() signal whenever a socket event corresponding to its type occurs. Connect the activated() signal to the slot you want to be called when an event corresponding to your socket notifier's type occurs.

You can create a socket notifier with no descriptor assigned. In this case, you should call the setSocket() function after the descriptor has been obtained.

There are three types of socket notifiers: read, write, and exception. The type is described by the \l Type enum, and must be specified when constructing the socket notifier. After construction it can be determined using the type() function. Note that if you need to monitor both reads and writes for the same file descriptor, you must create two socket notifiers. Note also that it is not possible to install two socket notifiers of the same type (\l Read, \l Write, \l Exception) on the same socket.

The setEnabled() function allows you to disable as well as enable the socket notifier. It is generally advisable to explicitly enable or disable the socket notifier, especially for write notifiers. A disabled notifier ignores socket events (the same effect as not creating the socket notifier). Use the isEnabled() function to determine the notifier's current status.

Finally, you can use the socket() function to retrieve the socket identifier. Although the class is called QSocketNotifier, it is normally used for other types of devices than sockets. QTcpSocket and QUdpSocket provide notification through signals, so there is normally no need to use a QSocketNotifier on them.

See also: QFile, QProcess, QTcpSocket, QUdpSocket

Definition at line 13 of file qsocketnotifier.h.

Member Enumeration Documentation

◆ Type

enum QSocketNotifier::Type

This enum describes the various types of events that a socket notifier can recognize.

The type must be specified when constructing the socket notifier.

Note that if you need to monitor both reads and writes for the same file descriptor, you must create two socket notifiers. Note also that it is not possible to install two socket notifiers of the same type (Read, Write, Exception) on the same socket.

\value Read There is data to be read. \value Write Data can be written. \value Exception An exception has occurred. We recommend against using this.

See also: QSocketNotifier(), type()

Enumerator
Read
Write
Exception

Definition at line 19 of file qsocketnotifier.h.

Constructor & Destructor Documentation

◆ QSocketNotifier() [1/2]

QSocketNotifier::QSocketNotifier	(	Type	type,
		QObject *	parent = nullptr )

explicit

Since: 6.1

Constructs a socket notifier with the given type that has no descriptor assigned. The parent argument is passed to QObject's constructor.

Call the setSocket() function to set the descriptor for monitoring.

See also: setSocket(), isValid(), isEnabled()

Definition at line 123 of file qsocketnotifier.cpp.

References d, and type().

Here is the call graph for this function:

◆ QSocketNotifier() [2/2]

QSocketNotifier::QSocketNotifier	(	qintptr	socket,
		Type	type,
		QObject *	parent = nullptr )

Constructs a socket notifier with the given parent.

It enables the socket, and watches for events of the given type.

It is generally advisable to explicitly enable or disable the socket notifier, especially for write notifiers.

{Note for Windows users:} The socket passed to QSocketNotifier will become non-blocking, even if it was created as a blocking socket.

See also: setEnabled(), isEnabled()

Definition at line 147 of file qsocketnotifier.cpp.

References d, qWarning, and socket().

Here is the call graph for this function:

◆ ~QSocketNotifier()

QSocketNotifier::~QSocketNotifier ( )

Destroys this socket notifier.

Definition at line 169 of file qsocketnotifier.cpp.

References setEnabled().

Here is the call graph for this function:

Member Function Documentation

◆ activated

void QSocketNotifier::activated	(	QSocketDescriptor	socket,
		QSocketNotifier::Type	activationEvent,
		QPrivateSignal	)

signal

Deprecated: To avoid unintended truncation of the descriptor, use the QSocketDescriptor overload of this function. If you need compatibility with versions older than 5.15 you need to change the slot to accept qintptr if it currently accepts an int, and then connect using Functor-Based Connection.

This signal is emitted whenever the socket notifier is enabled and a socket event corresponding to its \l {Type}{type} occurs.

The socket identifier is passed in the socket parameter.

See also: type(), socket()

Since: 5.15

This signal is emitted whenever the socket notifier is enabled and a socket event corresponding to its type occurs.

The socket identifier is passed in the socket parameter.

See also: type(), socket()

Referenced by BluetoothManagement::BluetoothManagement(), QBsdKeyboardHandler::QBsdKeyboardHandler(), QBsdMouseHandler::QBsdMouseHandler(), QEvdevKeyboardHandler::QEvdevKeyboardHandler(), QEvdevTabletHandler::QEvdevTabletHandler(), QEvdevTouchScreenHandler::QEvdevTouchScreenHandler(), QFbVtHandler::QFbVtHandler(), QLibInputHandler::QLibInputHandler(), QTsLibMouseHandler::QTsLibMouseHandler(), QPSQLDriver::close(), event(), qDBusAddWatch(), QEglFSKmsEventReaderThread::run(), QLowEnergyControllerPrivateBluez::startAdvertising(), QPSQLDriver::subscribeToNotification(), and QPSQLDriver::unsubscribeFromNotification().

Here is the caller graph for this function:

◆ event()

bool QSocketNotifier::event ( QEvent * e )

overrideprotectedvirtual

\reimp

Reimplemented from QObject.

Reimplemented in QWriteNotifier.

Definition at line 310 of file qsocketnotifier.cpp.

References activated(), d, emit, QObject::event(), QMetaObject::invokeMethod(), Q_ARG, Qt::QueuedConnection, setEnabled(), QEvent::SockAct, QEvent::SockClose, QEvent::ThreadChange, and QEvent::type().

Referenced by QReadNotifier::event(), QWriteNotifier::event(), and QExceptionNotifier::event().

Here is the call graph for this function:

Here is the caller graph for this function:

◆ isEnabled()

bool QSocketNotifier::isEnabled ( ) const

Returns true if the notifier is enabled; otherwise returns false.

See also: setEnabled()

Definition at line 262 of file qsocketnotifier.cpp.

References d.

◆ isValid()

bool QSocketNotifier::isValid ( ) const

Since: 6.1

Returns true if the notifier is valid (that is, it has a descriptor assigned); otherwise returns false.

See also: setSocket()

Definition at line 251 of file qsocketnotifier.cpp.

References d.

◆ setEnabled

void QSocketNotifier::setEnabled ( bool enable )

slot

If enable is true, the notifier is enabled; otherwise the notifier is disabled.

When the notifier is enabled, it emits the activated() signal whenever a socket event corresponding to its \l{type()}{type} occurs. When it is disabled, it ignores socket events (the same effect as not creating the socket notifier).

Write notifiers should normally be disabled immediately after the activated() signal has been emitted