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Qt
Internal/Contributor docs for the Qt SDK. Note: These are NOT official API docs; those are found at https://doc.qt.io/
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Qt
Internal/Contributor docs for the Qt SDK. Note: These are NOT official API docs; those are found at https://doc.qt.io/
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\reentrant More...
#include <qfuturewatcher.h>
Inheritance diagram for QFutureWatcher< T >: Collaboration diagram for QFutureWatcher< T >:Public Member Functions | |
| QFutureWatcher (QObject *_parent=nullptr) | |
| Constructs a new QFutureWatcher with the given parent. | |
| ~QFutureWatcher () | |
| Destroys the QFutureWatcher. | |
| void | setFuture (const QFuture< T > &future) |
| Starts watching the given future. | |
| QFuture< T > | future () const |
| Returns the watched future. | |
| template<typename U = T, typename = QtPrivate::EnableForNonVoid<U>> | |
| T | result () const |
| template<typename U = T, typename = QtPrivate::EnableForNonVoid<U>> | |
| T | resultAt (int index) const |
| Public Member Functions inherited from QFutureWatcherBase | |
| QFutureWatcherBase (QObject *parent=nullptr) | |
| int | progressValue () const |
| int | progressMinimum () const |
| int | progressMaximum () const |
| QString | progressText () const |
| bool | isStarted () const |
| bool | isFinished () const |
| bool | isRunning () const |
| bool | isCanceled () const |
| bool | isSuspending () const |
| bool | isSuspended () const |
| void | waitForFinished () |
| void | setPendingResultsLimit (int limit) |
| bool | event (QEvent *event) override |
| This virtual function receives events to an object and should return true if the event e was recognized and processed. | |
| 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. | |
Private Member Functions | |
| const QFutureInterfaceBase & | futureInterface () const override |
| QFutureInterfaceBase & | futureInterface () override |
Additional Inherited Members | |
| Public Slots inherited from QFutureWatcherBase | |
| void | cancel () |
| void | setSuspended (bool suspend) |
| void | suspend () |
| void | resume () |
| void | toggleSuspended () |
| Public Slots inherited from QObject | |
| void | deleteLater () |
| \threadsafe | |
| Signals inherited from QFutureWatcherBase | |
| void | started () |
| void | finished () |
| void | canceled () |
| void | suspending () |
| void | suspended () |
| void | resumed () |
| void | resultReadyAt (int resultIndex) |
| void | resultsReadyAt (int beginIndex, int endIndex) |
| void | progressRangeChanged (int minimum, int maximum) |
| void | progressValueChanged (int progressValue) |
| void | progressTextChanged (const QString &progressText) |
| 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) |
| Protected Member Functions inherited from QFutureWatcherBase | |
| void | connectNotify (const QMetaMethod &signal) override |
| void | disconnectNotify (const QMetaMethod &signal) override |
| void | connectOutputInterface () |
| void | disconnectOutputInterface (bool pendingAssignment=false) |
| 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. | |
| QObject (QObjectPrivate &dd, QObject *parent=nullptr) | |
| 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) | |
\reentrant
\inmodule QtCore
The QFutureWatcher class allows monitoring a QFuture using signals and slots.
QFutureWatcher provides information and notifications about a QFuture. Use the setFuture() function to start watching a particular QFuture. The future() function returns the future set with setFuture().
For convenience, several of QFuture's functions are also available in QFutureWatcher: progressValue(), progressMinimum(), progressMaximum(), progressText(), isStarted(), isFinished(), isRunning(), isCanceled(), isSuspending(), isSuspended(), waitForFinished(), result(), and resultAt(). The cancel(), setSuspended(), suspend(), resume(), and toggleSuspended() functions are slots in QFutureWatcher.
Status changes are reported via the started(), finished(), canceled(), suspending(), suspended(), resumed(), resultReadyAt(), and resultsReadyAt() signals. Progress information is provided from the progressRangeChanged(), void progressValueChanged(), and progressTextChanged() signals.
Throttling control is provided by the setPendingResultsLimit() function. When the number of pending resultReadyAt() or resultsReadyAt() signals exceeds the limit, the computation represented by the future will be throttled automatically. The computation will resume once the number of pending signals drops below the limit.
Example: Starting a computation and getting a slot callback when it's finished:
Be aware that not all running asynchronous computations can be canceled or suspended. For example, the future returned by QtConcurrent::run() cannot be canceled; but the future returned by QtConcurrent::mappedReduced() can.
QFutureWatcher<void> is specialized to not contain any of the result fetching functions. Any QFuture<T> can be watched by a QFutureWatcher<void> as well. This is useful if only status or progress information is needed; not the actual result data.
Definition at line 99 of file qfuturewatcher.h.
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inlineexplicit |
Constructs a new QFutureWatcher with the given parent.
Until a future is set with setFuture(), the functions isStarted(), isCanceled(), and isFinished() return true.
Definition at line 102 of file qfuturewatcher.h.
Referenced by QFutureWatcher< QQmlXmlListModelQueryResult >::QFutureWatcher().
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inline |
Destroys the QFutureWatcher.
Definition at line 105 of file qfuturewatcher.h.
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inline |
Returns the watched future.
Definition at line 109 of file qfuturewatcher.h.
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inlineoverrideprivatevirtual |
Implements QFutureWatcherBase.
Definition at line 170 of file qfuturewatcher.h.
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inlineoverrideprivatevirtual |
Implements QFutureWatcherBase.
Definition at line 171 of file qfuturewatcher.h.
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inline |
Definition at line 113 of file qfuturewatcher.h.
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inline |
Definition at line 116 of file qfuturewatcher.h.
| Q_INLINE_TEMPLATE void QFutureWatcher< T >::setFuture | ( | const QFuture< T > & | future | ) |
Starts watching the given future.
If future has already started, the watcher will initially emit signals that bring their listeners up to date about the future's state. The following signals will, if applicable, be emitted in the given order: started(), progressRangeChanged(), progressValueChanged(), progressTextChanged(), resultsReadyAt(), resultReadyAt(), suspending(), suspended(), canceled(), and finished(). Of these, resultsReadyAt() and resultReadyAt() may be emitted several times to cover all available results. progressValueChanged() and progressTextChanged() will only be emitted once for the latest available progress value and text.
To avoid a race condition, it is important to call this function after doing the connections.
Definition at line 175 of file qfuturewatcher.h.
1.13.2