\inmodule QtCore More...

#include <qchronotimer.h>

Inheritance diagram for QChronoTimer:

Collaboration diagram for QChronoTimer:

Public Slots
void	start ()

void	stop ()
	Stops the timer.

Public Slots inherited from QObject
void	deleteLater ()
	\threadsafe

Signals
void	timeout (QPrivateSignal)
	This signal is emitted when the timer times out.

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
	QChronoTimer (std::chrono::nanoseconds nsec, QObject *parent=nullptr)
	Constructs a timer with the given parent, using an interval of nsec.

	QChronoTimer (QObject *parent=nullptr)
	Constructs a timer with the given parent, using the default interval, `0ns`.

	~QChronoTimer () override
	Destroys the timer.

bool	isActive () const
	Returns `true` if the timer is running; otherwise returns `false`.

QBindable< bool >	bindableActive ()

Qt::TimerId	id () const
	Returns a Qt::TimerId representing the timer ID if the timer is running; otherwise returns `Qt::TimerId::Invalid`.

void	setInterval (std::chrono::nanoseconds nsec)

std::chrono::nanoseconds	interval () const

QBindable< std::chrono::nanoseconds >	bindableInterval ()

std::chrono::nanoseconds	remainingTime () const

void	setTimerType (Qt::TimerType atype)

Qt::TimerType	timerType () const

QBindable< Qt::TimerType >	bindableTimerType ()

void	setSingleShot (bool singleShot)

bool	isSingleShot () const

QBindable< bool >	bindableSingleShot ()

template<typename ... Args>
QMetaObject::Connection	callOnTimeout (Args &&...args)

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.

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
void	timerEvent (QTimerEvent *) 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	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)

Properties
bool	singleShot
	Whether the timer is a single-shot timer.

std::chrono::nanoseconds	interval
	The timeout interval.

std::chrono::nanoseconds	remainingTime
	The remaining time.

Qt::TimerType	timerType
	Controls the accuracy of the timer.

bool	active
	This boolean property is `true` if the timer is running; otherwise `false`.

Properties inherited from QObject
QString	objectName
	the name of this object

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

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

Since: 6.8

The QChronoTimer class provides repetitive and single-shot timers.

The QChronoTimer class provides a high-level programming interface for timers. To use it, create a QChronoTimer, either passing the interval to the constructor, or setting it after construction using setInterval(), connect its timeout() signal to the appropriate slots, and call start(). From then on, it will emit the timeout() signal at constant intervals. For example:

        QChronoTimer *timer = new QChronoTimer(1s, this);
        connect(timer, &QChronoTimer::timeout, this, &MyWidget::processOneThing);
        timer->start();

        QChronoTimer *timer = new QChronoTimer(this);
        connect(timer, &QChronoTimer::timeout, this, &MyWidget::processOneThing);
        timer->setInterval(1s);
        timer->start();

You can set a timer to time out only once by calling setSingleShot(true).

Note: QChronoTimer has no singleShot() static methods, as the ones on QTimer already work with chrono types and nanoseconds resolution.

In multithreaded applications, you can use QChronoTimer in any thread that has an event loop. To start an event loop from a non-GUI thread, use QThread::exec(). Qt uses the timer's \l{QObject::thread()}{thread affinity} to determine which thread will emit the \l{QChronoTimer::}{timeout()} signal. Because of this, you must start and stop the timer in its thread; it is not possible to start a timer from another thread.

As a special case, a QChronoTimer with a timeout of 0ns will time out as soon as possible, though the ordering between zero timers and other sources of events is unspecified. Zero timers can be used to do some work while still providing a responsive user interface:

        // The default interval is 0ns
        QChronoTimer *timer = new QChronoTimer(this);
        connect(timer, &QChronoTimer::timeout, this, &MyWidget::processOneThing);
        timer->start();

From then on, processOneThing() will be called repeatedly. It should be written in such a way that it always returns quickly (for example, after processing one data item) so that Qt can deliver events to the user interface and stop the timer as soon as it has done all its work. This is the traditional way of implementing heavy work in GUI applications, but as multithreading is becoming available on more platforms, a modern alternative is doing the heavy work in a thread other than the GUI (main) thread. Qt has the QThread class, which can be used to achieve that.

Definition at line 20 of file qchronotimer.h.

Constructor & Destructor Documentation

◆ QChronoTimer() [1/2]

QChronoTimer::QChronoTimer	(	std::chrono::nanoseconds	nsec,
		QObject *	parent = nullptr )

explicit

Constructs a timer with the given parent, using an interval of nsec.

Definition at line 121 of file qchronotimer.cpp.

◆ QChronoTimer() [2/2]

QChronoTimer::QChronoTimer ( QObject * parent = nullptr )

explicit

Constructs a timer with the given parent, using the default interval, 0ns.

Definition at line 113 of file qchronotimer.cpp.

◆ ~QChronoTimer()

QChronoTimer::~QChronoTimer ( )

override

Destroys the timer.

Definition at line 130 of file qchronotimer.cpp.

Member Function Documentation

◆ bindableActive()

QBindable< bool > QChronoTimer::bindableActive ( )

Definition at line 159 of file qchronotimer.cpp.

◆ bindableInterval()

QBindable< std::chrono::nanoseconds > QChronoTimer::bindableInterval ( )

Definition at line 312 of file qchronotimer.cpp.

◆ bindableSingleShot()

QBindable< bool > QChronoTimer::bindableSingleShot ( )

Definition at line 264 of file qchronotimer.cpp.

◆ bindableTimerType()

QBindable< Qt::TimerType > QChronoTimer::bindableTimerType ( )

Definition at line 354 of file qchronotimer.cpp.

◆ callOnTimeout()

template<typename ... Args>

QMetaObject::Connection QChronoTimer::callOnTimeout ( Args &&... args )

inline

Definition at line 64 of file qchronotimer.h.

◆ id()

Qt::TimerId QChronoTimer::id ( ) const

Returns a Qt::TimerId representing the timer ID if the timer is running; otherwise returns Qt::TimerId::Invalid.

See also: Qt::TimerId

Definition at line 170 of file qchronotimer.cpp.

◆ interval()

std::chrono::nanoseconds QChronoTimer::interval ( ) const

Definition at line 307 of file qchronotimer.cpp.

◆ isActive()

bool QChronoTimer::isActive ( ) const

Returns true if the timer is running; otherwise returns false.

Definition at line 154 of file qchronotimer.cpp.

◆ isSingleShot()

bool QChronoTimer::isSingleShot ( ) const

Definition at line 259 of file qchronotimer.cpp.

◆ remainingTime()

std::chrono::nanoseconds QChronoTimer::remainingTime ( ) const

Definition at line 329 of file qchronotimer.cpp.

◆ setInterval()

void QChronoTimer::setInterval ( std::chrono::nanoseconds nsec )

Definition at line 284 of file qchronotimer.cpp.

◆ setSingleShot()

void QChronoTimer::setSingleShot ( bool singleShot )

Definition at line 254 of file qchronotimer.cpp.

◆ setTimerType()

void QChronoTimer::setTimerType ( Qt::TimerType atype )

Definition at line 344 of file qchronotimer.cpp.

◆ start

void QChronoTimer::start ( )

slot

Definition at line 187 of file qchronotimer.cpp.

◆ stop

void QChronoTimer::stop ( )

slot

Stops the timer.

See also: start()

Definition at line 204 of file qchronotimer.cpp.

◆ timeout

void QChronoTimer::timeout ( QPrivateSignal )

signal

This signal is emitted when the timer times out.

See also: interval, start(), stop()

◆ timerEvent()

void QChronoTimer::timerEvent ( QTimerEvent * e )

overrideprotectedvirtual

\reimp

Reimplemented from QObject.

Definition at line 217 of file qchronotimer.cpp.

◆ timerType()

Qt::TimerType QChronoTimer::timerType ( ) const

Definition at line 349 of file qchronotimer.cpp.

Property Documentation

◆ active

bool QChronoTimer::active

read

This boolean property is true if the timer is running; otherwise false.

Definition at line 30 of file qchronotimer.h.

◆ interval

std::chrono::nanoseconds QChronoTimer::interval

readwrite

The timeout interval.

The default value for this property is 0ns.

A QChronoTimer with a timeout of 0ns will time out as soon as all the events in the window system's event queue have been processed.

Setting the interval of a running timer will change the interval, stop() and then start() the timer, and acquire a new id(). If the timer is not running, only the interval is changed.

See also: singleShot

Definition at line 25 of file qchronotimer.h.

◆ remainingTime

std::chrono::nanoseconds QChronoTimer::remainingTime

read

The remaining time.

Returns the remaining duration until the timeout.

If the timer is inactive, the returned duration will be negative.

If the timer is overdue, the returned duration will be 0ns.

See also: interval

Definition at line 27 of file qchronotimer.h.

◆ singleShot

bool QChronoTimer::singleShot

readwrite

Whether the timer is a single-shot timer.

A single-shot timer fires only once, non-single-shot timers fire every \l interval.

The default value for this property is false.

See also: interval, QChronoTimer::singleShot()

Definition at line 23 of file qchronotimer.h.

◆ timerType

Qt::TimerType QChronoTimer::timerType

readwrite

Controls the accuracy of the timer.

The default value for this property is Qt::CoarseTimer.

See also: Qt::TimerType

Definition at line 28 of file qchronotimer.h.

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

qtbase/src/corelib/kernel/qchronotimer.h (6e5eb082c934cb94c45f3e13b3f7c2deb2e7b2e6)
qtbase/src/corelib/kernel/qchronotimer.cpp (e1fdfe9da8ccdeed9af602897232a513884b0515)

Public Slots

Signals

Public Member Functions

Protected Member Functions

Properties

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ QChronoTimer() [1/2]

◆ QChronoTimer() [2/2]

◆ ~QChronoTimer()

Member Function Documentation

◆ bindableActive()

◆ bindableInterval()

◆ bindableSingleShot()

◆ bindableTimerType()

◆ callOnTimeout()

◆ id()

◆ interval()

◆ isActive()

◆ isSingleShot()

◆ remainingTime()

◆ setInterval()

◆ setSingleShot()

◆ setTimerType()

◆ start

◆ stop

◆ timeout

◆ timerEvent()

◆ timerType()

Property Documentation

◆ active

◆ interval

◆ remainingTime

◆ singleShot

◆ timerType