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

#include <qsocketnotifier.h>

Inheritance diagram for QSocketNotifier:

Collaboration diagram for QSocketNotifier:

Public Types
enum	Type { Read , Write , Exception }

Public Slots
void	setEnabled (bool)

Public Slots inherited from QObject
void	deleteLater ()

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

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

void	objectNameChanged (const QString &objectName, QPrivateSignal)

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

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

	~QSocketNotifier ()

void	setSocket (qintptr socket)

qintptr	socket () const

Type	type () const

bool	isValid () const

bool	isEnabled () const

Public Member Functions inherited from QObject
Q_INVOKABLE	QObject (QObject *parent=nullptr)

virtual	~QObject ()

virtual bool	eventFilter (QObject watched, QEvent event)

QString	objectName () const

void	setObjectName (const QString &name)

QBindable< QString >	bindableObjectName ()

bool	isWidgetType () const

bool	isWindowType () const

bool	signalsBlocked () const noexcept

bool	blockSignals (bool b) noexcept

QThread *	thread () const

void	moveToThread (QThread *thread)

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

void	killTimer (int id)

template<typename T >
T	findChild (const QString &aName=QString(), Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

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

template<typename T >
QList< T >	findChildren (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

const QObjectList &	children () const

void	setParent (QObject *parent)

void	installEventFilter (QObject *filterObj)

void	removeEventFilter (QObject *obj)

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

void	dumpObjectInfo () const

bool	setProperty (const char *name, const QVariant &value)

QVariant	property (const char *name) const

QList< QByteArray >	dynamicPropertyNames () const

QBindingStorage *	bindingStorage ()

const QBindingStorage *	bindingStorage () const

QObject *	parent () const

bool	inherits (const char *classname) const

Protected Member Functions
bool	event (QEvent *) override

Protected Member Functions inherited from QObject
QObject *	sender () const

int	senderSignalIndex () const

int	receivers (const char *signal) const

bool	isSignalConnected (const QMetaMethod &signal) const

virtual void	timerEvent (QTimerEvent *event)

virtual void	childEvent (QChildEvent *event)

virtual void	customEvent (QEvent *event)

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)

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::FunctionPointer< Func2 >::Object receiver, Func2 slot, Qt::ConnectionType type=Qt::AutoConnection)

static QMetaObject::Connection ::type	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 slot)

static QMetaObject::Connection ::type	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const QObject context, Func2 slot, Qt::ConnectionType type=Qt::AutoConnection)

template<typename Func1 , typename Func2 >
static std::enable_if< QtPrivate::FunctionPointer< Func2 >::ArgumentCount==-1 &&!std::is_convertible_v< Func2, const char * >, QMetaObject::Connection >::type	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 slot)

template<typename Func1 , typename Func2 >
static std::enable_if< QtPrivate::FunctionPointer< Func2 >::ArgumentCount==-1 &&!std::is_convertible_v< Func2, const char * >, QMetaObject::Connection >::type	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const QObject context, Func2 slot, Qt::ConnectionType type=Qt::AutoConnection)

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

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

static bool	disconnect (const QMetaObject::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 More...

Related Functions inherited from QObject
template< class T > T	qobject_cast (const QObject *object)

template< typename T > T	qFindChildqFindChildren (const QObject *obj, const QString &name)()

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

	QObjectList

Detailed Description

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

\inmodule QtCore

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 49 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 55 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 158 of file qsocketnotifier.cpp.

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◆ 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 182 of file qsocketnotifier.cpp.

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◆ ~QSocketNotifier()

QSocketNotifier::~QSocketNotifier ( )

Destroys this socket notifier.

Definition at line 204 of file qsocketnotifier.cpp.

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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()

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◆ event()

bool QSocketNotifier::event ( QEvent * e )

overrideprotectedvirtual

\reimp

Reimplemented from QObject.

Reimplemented in QExceptionNotifier, QWriteNotifier, and QReadNotifier.

Definition at line 345 of file qsocketnotifier.cpp.

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◆ isEnabled()

bool QSocketNotifier::isEnabled ( ) const

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

See also: setEnabled()

Definition at line 297 of file qsocketnotifier.cpp.

◆ 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 286 of file qsocketnotifier.cpp.

◆ 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

See also: isEnabled(), activated()

Definition at line 318 of file qsocketnotifier.cpp.

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◆ setSocket()

void QSocketNotifier::setSocket ( qintptr socket )

Since: 6.1

Assigns the socket to this notifier.

Note: The notifier will be disabled as a side effect and needs to be re-enabled.

See also: setEnabled(), isValid()

Definition at line 248 of file qsocketnotifier.cpp.

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◆ socket()

qintptr QSocketNotifier::socket ( ) const

Returns the socket identifier assigned to this object.

See also: isValid(), type()

Definition at line 261 of file qsocketnotifier.cpp.

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◆ type()

QSocketNotifier::Type QSocketNotifier::type ( ) const

Returns the socket event type specified to the constructor.

See also: socket()

Definition at line 272 of file qsocketnotifier.cpp.

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

src/corelib/kernel/qsocketnotifier.h
src/corelib/kernel/qsocketnotifier.cpp

Public Types

Public Slots

Signals

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ Type

Constructor & Destructor Documentation

◆ QSocketNotifier() [1/2]

◆ QSocketNotifier() [2/2]

◆ ~QSocketNotifier()

Member Function Documentation

◆ activated

◆ event()

◆ isEnabled()

◆ isValid()

◆ setEnabled

◆ setSocket()

◆ socket()

◆ type()