Struct qt_core::QThreadPool

#[repr(C)]
pub struct QThreadPool { /* private fields */ }

The QThreadPool class manages a collection of QThreads.

C++ class: QThreadPool.

C++ documentation:

The QThreadPool class manages a collection of QThreads.

QThreadPool manages and recyles individual QThread objects to help reduce thread creation costs in programs that use threads. Each Qt application has one global QThreadPool object, which can be accessed by calling globalInstance().

To use one of the QThreadPool threads, subclass QRunnable and implement the run() virtual function. Then create an object of that class and pass it to QThreadPool::start().

class HelloWorldTask : public QRunnable
{
      void run()
      {
          qDebug() << “Hello world from thread” << QThread::currentThread();
      }
};
HelloWorldTask *hello = new HelloWorldTask();
// QThreadPool takes ownership and deletes ‘hello’ automatically
QThreadPool::globalInstance()->start(hello);

QThreadPool deletes the QRunnable automatically by default. Use QRunnable::setAutoDelete() to change the auto-deletion flag.

QThreadPool supports executing the same QRunnable more than once by calling tryStart(this) from within QRunnable::run(). If autoDelete is enabled the QRunnable will be deleted when the last thread exits the run function. Calling start() multiple times with the same QRunnable when autoDelete is enabled creates a race condition and is not recommended.

Threads that are unused for a certain amount of time will expire. The default expiry timeout is 30000 milliseconds (30 seconds). This can be changed using setExpiryTimeout(). Setting a negative expiry timeout disables the expiry mechanism.

Call maxThreadCount() to query the maximum number of threads to be used. If needed, you can change the limit with setMaxThreadCount(). The default maxThreadCount() is QThread::idealThreadCount(). The activeThreadCount() function returns the number of threads currently doing work.

The reserveThread() function reserves a thread for external use. Use releaseThread() when your are done with the thread, so that it may be reused. Essentially, these functions temporarily increase or reduce the active thread count and are useful when implementing time-consuming operations that are not visible to the QThreadPool.

Note that QThreadPool is a low-level class for managing threads, see the Qt Concurrent module for higher level alternatives.

Implementations

impl QThreadPool

pub unsafe fn active_thread_count(&self) -> c_int

This property represents the number of active threads in the thread pool.

Calls C++ function: int QThreadPool::activeThreadCount() const.

C++ documentation:

This property represents the number of active threads in the thread pool.

Note: It is possible for this function to return a value that is greater than maxThreadCount(). See reserveThread() for more details.

Access functions:

int	activeThreadCount() const

See also reserveThread() and releaseThread().

pub unsafe fn cancel(&self, runnable: impl CastInto<Ptr<QRunnable>>)

Removes the specified runnable from the queue if it is not yet started. The runnables for which runnable->autoDelete() returns true are deleted.

Calls C++ function: void QThreadPool::cancel(QRunnable* runnable).

C++ documentation:

Removes the specified runnable from the queue if it is not yet started. The runnables for which runnable->autoDelete() returns true are deleted.

This function was introduced in Qt 5.5.

See also start() and tryTake().

pub unsafe fn clear(&self)

Removes the runnables that are not yet started from the queue. The runnables for which runnable->autoDelete() returns true are deleted.

Calls C++ function: void QThreadPool::clear().

C++ documentation:

Removes the runnables that are not yet started from the queue. The runnables for which runnable->autoDelete() returns true are deleted.

This function was introduced in Qt 5.2.

See also start().

pub unsafe fn expiry_timeout(&self) -> c_int

Threads that are unused for expiryTimeout milliseconds are considered to have expired and will exit. Such threads will be restarted as needed. The default expiryTimeout is 30000 milliseconds (30 seconds). If expiryTimeout is negative, newly created threads will not expire, e.g., they will not exit until the thread pool is destroyed.

Calls C++ function: int QThreadPool::expiryTimeout() const.

C++ documentation:

Threads that are unused for expiryTimeout milliseconds are considered to have expired and will exit. Such threads will be restarted as needed. The default expiryTimeout is 30000 milliseconds (30 seconds). If expiryTimeout is negative, newly created threads will not expire, e.g., they will not exit until the thread pool is destroyed.

Note that setting expiryTimeout has no effect on already running threads. Only newly created threads will use the new expiryTimeout. We recommend setting the expiryTimeout immediately after creating the thread pool, but before calling start().

Access functions:

int	expiryTimeout() const
void	setExpiryTimeout(int expiryTimeout)

pub unsafe fn global_instance() -> QPtr<QThreadPool>

Returns the global QThreadPool instance.

Calls C++ function: static QThreadPool* QThreadPool::globalInstance().

C++ documentation:

Returns the global QThreadPool instance.

pub unsafe fn max_thread_count(&self) -> c_int

This property represents the maximum number of threads used by the thread pool.

Calls C++ function: int QThreadPool::maxThreadCount() const.

C++ documentation:

This property represents the maximum number of threads used by the thread pool.

Note: The thread pool will always use at least 1 thread, even if maxThreadCount limit is zero or negative.

The default maxThreadCount is QThread::idealThreadCount().

Access functions:

int	maxThreadCount() const
void	setMaxThreadCount(int maxThreadCount)

pub unsafe fn meta_object(&self) -> Ptr<QMetaObject>

Calls C++ function: virtual const QMetaObject* QThreadPool::metaObject() const.

pub unsafe fn new_1a(parent: impl CastInto<Ptr<QObject>>) -> QBox<QThreadPool>

Constructs a thread pool with the given parent.

Calls C++ function: [constructor] void QThreadPool::QThreadPool(QObject* parent = …).

C++ documentation:

Constructs a thread pool with the given parent.

pub unsafe fn new_0a() -> QBox<QThreadPool>

The QThreadPool class manages a collection of QThreads.

Calls C++ function: [constructor] void QThreadPool::QThreadPool().

C++ documentation:

The QThreadPool class manages a collection of QThreads.

QThreadPool manages and recyles individual QThread objects to help reduce thread creation costs in programs that use threads. Each Qt application has one global QThreadPool object, which can be accessed by calling globalInstance().

To use one of the QThreadPool threads, subclass QRunnable and implement the run() virtual function. Then create an object of that class and pass it to QThreadPool::start().

class HelloWorldTask : public QRunnable
{
      void run()
      {
          qDebug() << “Hello world from thread” << QThread::currentThread();
      }
};
HelloWorldTask *hello = new HelloWorldTask();
// QThreadPool takes ownership and deletes ‘hello’ automatically
QThreadPool::globalInstance()->start(hello);

QThreadPool deletes the QRunnable automatically by default. Use QRunnable::setAutoDelete() to change the auto-deletion flag.

QThreadPool supports executing the same QRunnable more than once by calling tryStart(this) from within QRunnable::run(). If autoDelete is enabled the QRunnable will be deleted when the last thread exits the run function. Calling start() multiple times with the same QRunnable when autoDelete is enabled creates a race condition and is not recommended.

Threads that are unused for a certain amount of time will expire. The default expiry timeout is 30000 milliseconds (30 seconds). This can be changed using setExpiryTimeout(). Setting a negative expiry timeout disables the expiry mechanism.

Call maxThreadCount() to query the maximum number of threads to be used. If needed, you can change the limit with setMaxThreadCount(). The default maxThreadCount() is QThread::idealThreadCount(). The activeThreadCount() function returns the number of threads currently doing work.

The reserveThread() function reserves a thread for external use. Use releaseThread() when your are done with the thread, so that it may be reused. Essentially, these functions temporarily increase or reduce the active thread count and are useful when implementing time-consuming operations that are not visible to the QThreadPool.

Note that QThreadPool is a low-level class for managing threads, see the Qt Concurrent module for higher level alternatives.

pub unsafe fn qt_metacall( &self, arg1: Call, arg2: c_int, arg3: *mut *mut c_void ) -> c_int

Calls C++ function: virtual int QThreadPool::qt_metacall(QMetaObject::Call arg1, int arg2, void** arg3).

pub unsafe fn qt_metacast(&self, arg1: *const c_char) -> *mut c_void

Calls C++ function: virtual void* QThreadPool::qt_metacast(const char* arg1).

pub unsafe fn release_thread(&self)

Releases a thread previously reserved by a call to reserveThread().

Calls C++ function: void QThreadPool::releaseThread().

C++ documentation:

Releases a thread previously reserved by a call to reserveThread().

Note: Calling this function without previously reserving a thread temporarily increases maxThreadCount(). This is useful when a thread goes to sleep waiting for more work, allowing other threads to continue. Be sure to call reserveThread() when done waiting, so that the thread pool can correctly maintain the activeThreadCount().

See also reserveThread().

pub unsafe fn reserve_thread(&self)

Reserves one thread, disregarding activeThreadCount() and maxThreadCount().

Calls C++ function: void QThreadPool::reserveThread().

C++ documentation:

Reserves one thread, disregarding activeThreadCount() and maxThreadCount().

Once you are done with the thread, call releaseThread() to allow it to be reused.

Note: This function will always increase the number of active threads. This means that by using this function, it is possible for activeThreadCount() to return a value greater than maxThreadCount() .

See also releaseThread().

pub unsafe fn set_expiry_timeout(&self, expiry_timeout: c_int)

Threads that are unused for expiryTimeout milliseconds are considered to have expired and will exit. Such threads will be restarted as needed. The default expiryTimeout is 30000 milliseconds (30 seconds). If expiryTimeout is negative, newly created threads will not expire, e.g., they will not exit until the thread pool is destroyed.

Calls C++ function: void QThreadPool::setExpiryTimeout(int expiryTimeout).

C++ documentation:

Threads that are unused for expiryTimeout milliseconds are considered to have expired and will exit. Such threads will be restarted as needed. The default expiryTimeout is 30000 milliseconds (30 seconds). If expiryTimeout is negative, newly created threads will not expire, e.g., they will not exit until the thread pool is destroyed.

Note that setting expiryTimeout has no effect on already running threads. Only newly created threads will use the new expiryTimeout. We recommend setting the expiryTimeout immediately after creating the thread pool, but before calling start().

Access functions:

int	expiryTimeout() const
void	setExpiryTimeout(int expiryTimeout)

pub unsafe fn set_max_thread_count(&self, max_thread_count: c_int)

This property represents the maximum number of threads used by the thread pool.

Calls C++ function: void QThreadPool::setMaxThreadCount(int maxThreadCount).

C++ documentation:

This property represents the maximum number of threads used by the thread pool.

Note: The thread pool will always use at least 1 thread, even if maxThreadCount limit is zero or negative.

The default maxThreadCount is QThread::idealThreadCount().

Access functions:

int	maxThreadCount() const
void	setMaxThreadCount(int maxThreadCount)

pub unsafe fn set_stack_size(&self, stack_size: c_uint)

Available on cpp_lib_version="5.11.3" or cpp_lib_version="5.12.2" or cpp_lib_version="5.13.0" or cpp_lib_version="5.14.0" only.

This property contains the stack size for the thread pool worker threads.

Calls C++ function: void QThreadPool::setStackSize(unsigned int stackSize).

C++ documentation:

This property contains the stack size for the thread pool worker threads.

The value of the property is only used when the thread pool creates new threads. Changing it has no effect for already created or running threads.

The default value is 0, which makes QThread use the operating system default stack size.

This property was introduced in Qt 5.10.

Access functions:

uint	stackSize() const
void	setStackSize(uint stackSize)

pub unsafe fn stack_size(&self) -> c_uint

Available on cpp_lib_version="5.11.3" or cpp_lib_version="5.12.2" or cpp_lib_version="5.13.0" or cpp_lib_version="5.14.0" only.

This property contains the stack size for the thread pool worker threads.

Calls C++ function: unsigned int QThreadPool::stackSize() const.

C++ documentation:

This property contains the stack size for the thread pool worker threads.

The value of the property is only used when the thread pool creates new threads. Changing it has no effect for already created or running threads.

The default value is 0, which makes QThread use the operating system default stack size.

This property was introduced in Qt 5.10.

Access functions:

uint	stackSize() const
void	setStackSize(uint stackSize)

pub unsafe fn start_2a( &self, runnable: impl CastInto<Ptr<QRunnable>>, priority: c_int )

Reserves a thread and uses it to run runnable, unless this thread will make the current thread count exceed maxThreadCount(). In that case, runnable is added to a run queue instead. The priority argument can be used to control the run queue's order of execution.

Calls C++ function: void QThreadPool::start(QRunnable* runnable, int priority = …).

C++ documentation:

Reserves a thread and uses it to run runnable, unless this thread will make the current thread count exceed maxThreadCount(). In that case, runnable is added to a run queue instead. The priority argument can be used to control the run queue’s order of execution.

Note that the thread pool takes ownership of the runnable if runnable->autoDelete() returns true, and the runnable will be deleted automatically by the thread pool after the runnable->run() returns. If runnable->autoDelete() returns false, ownership of runnable remains with the caller. Note that changing the auto-deletion on runnable after calling this functions results in undefined behavior.

pub unsafe fn start_1a(&self, runnable: impl CastInto<Ptr<QRunnable>>)

Reserves a thread and uses it to run runnable, unless this thread will make the current thread count exceed maxThreadCount(). In that case, runnable is added to a run queue instead. The priority argument can be used to control the run queue's order of execution.

Calls C++ function: void QThreadPool::start(QRunnable* runnable).

C++ documentation:

Reserves a thread and uses it to run runnable, unless this thread will make the current thread count exceed maxThreadCount(). In that case, runnable is added to a run queue instead. The priority argument can be used to control the run queue’s order of execution.

Note that the thread pool takes ownership of the runnable if runnable->autoDelete() returns true, and the runnable will be deleted automatically by the thread pool after the runnable->run() returns. If runnable->autoDelete() returns false, ownership of runnable remains with the caller. Note that changing the auto-deletion on runnable after calling this functions results in undefined behavior.

pub unsafe fn static_meta_object() -> Ref<QMetaObject>

Returns a reference to the staticMetaObject field.

pub unsafe fn tr( s: *const c_char, c: *const c_char, n: c_int ) -> CppBox<QString>

Calls C++ function: static QString QThreadPool::tr(const char* s, const char* c, int n).

pub unsafe fn tr_utf8( s: *const c_char, c: *const c_char, n: c_int ) -> CppBox<QString>

Calls C++ function: static QString QThreadPool::trUtf8(const char* s, const char* c, int n).

pub unsafe fn try_start(&self, runnable: impl CastInto<Ptr<QRunnable>>) -> bool

Attempts to reserve a thread to run runnable.

Calls C++ function: bool QThreadPool::tryStart(QRunnable* runnable).

C++ documentation:

Attempts to reserve a thread to run runnable.

If no threads are available at the time of calling, then this function does nothing and returns false. Otherwise, runnable is run immediately using one available thread and this function returns true.

Note that the thread pool takes ownership of the runnable if runnable->autoDelete() returns true, and the runnable will be deleted automatically by the thread pool after the runnable->run() returns. If runnable->autoDelete() returns false, ownership of runnable remains with the caller. Note that changing the auto-deletion on runnable after calling this function results in undefined behavior.

pub unsafe fn try_take(&self, runnable: impl CastInto<Ptr<QRunnable>>) -> bool

Attempts to remove the specified runnable from the queue if it is not yet started. If the runnable had not been started, returns true, and ownership of runnable is transferred to the caller (even when runnable->autoDelete() == true). Otherwise returns false.

Calls C++ function: bool QThreadPool::tryTake(QRunnable* runnable).

C++ documentation:

Attempts to remove the specified runnable from the queue if it is not yet started. If the runnable had not been started, returns true, and ownership of runnable is transferred to the caller (even when runnable->autoDelete() == true). Otherwise returns false.

Note: If runnable->autoDelete() == true, this function may remove the wrong runnable. This is known as the ABA problem: the original runnable may already have executed and has since been deleted. The memory is re-used for another runnable, which then gets removed instead of the intended one. For this reason, we recommend calling this function only for runnables that are not auto-deleting.

This function was introduced in Qt 5.9.

See also start() and QRunnable::autoDelete().

pub unsafe fn wait_for_done_1a(&self, msecs: c_int) -> bool

Waits up to msecs milliseconds for all threads to exit and removes all threads from the thread pool. Returns true if all threads were removed; otherwise it returns false. If msecs is -1 (the default), the timeout is ignored (waits for the last thread to exit).

Calls C++ function: bool QThreadPool::waitForDone(int msecs = …).

C++ documentation:

Waits up to msecs milliseconds for all threads to exit and removes all threads from the thread pool. Returns true if all threads were removed; otherwise it returns false. If msecs is -1 (the default), the timeout is ignored (waits for the last thread to exit).

pub unsafe fn wait_for_done_0a(&self) -> bool

Waits up to msecs milliseconds for all threads to exit and removes all threads from the thread pool. Returns true if all threads were removed; otherwise it returns false. If msecs is -1 (the default), the timeout is ignored (waits for the last thread to exit).

Calls C++ function: bool QThreadPool::waitForDone().

C++ documentation:

Waits up to msecs milliseconds for all threads to exit and removes all threads from the thread pool. Returns true if all threads were removed; otherwise it returns false. If msecs is -1 (the default), the timeout is ignored (waits for the last thread to exit).

Methods from Deref<Target = QObject>

pub unsafe fn find_child<T>( &self, name: &str ) -> Result<QPtr<T>, FindChildError>

where QObject: DynamicCast<T>, T: StaticUpcast<QObject>,

Finds a child of self with the specified object name and casts it to type T.

The search is performed recursively. If there is more than one child matching the search, the most direct ancestor is returned. If there are several direct ancestors, it is undefined which one will be returned.

Returns an error if there is no child object with object name name or the found object cannot be cast to T.

pub fn destroyed(&self) -> Signal<(*mut QObject,)>

This signal is emitted immediately before the object obj is destroyed, and can not be blocked.

Returns a built-in Qt signal QObject::destroyed that can be passed to qt_core::Signal::connect.

C++ documentation:

This signal is emitted immediately before the object obj is destroyed, and can not be blocked.

All the objects's children are destroyed immediately after this signal is emitted.

See also deleteLater() and QPointer.

pub fn object_name_changed(&self) -> Signal<(*const QString,)>

This signal is emitted after the object's name has been changed. The new object name is passed as objectName.

Returns a built-in Qt signal QObject::objectNameChanged that can be passed to qt_core::Signal::connect.

C++ documentation:

This signal is emitted after the object’s name has been changed. The new object name is passed as objectName.

Note: This is a private signal. It can be used in signal connections but cannot be emitted by the user.

Note: Notifier signal for property objectName.

See also QObject::objectName.

pub fn slot_delete_later(&self) -> Receiver<()>

Schedules this object for deletion.

Returns a built-in Qt slot QObject::deleteLater that can be passed to qt_core::Signal::connect.

C++ documentation:

Schedules this object for deletion.

The object will be deleted when control returns to the event loop. If the event loop is not running when this function is called (e.g. deleteLater() is called on an object before QCoreApplication::exec()), the object will be deleted once the event loop is started. If deleteLater() is called after the main event loop has stopped, the object will not be deleted. Since Qt 4.8, if deleteLater() is called on an object that lives in a thread with no running event loop, the object will be destroyed when the thread finishes.

Note that entering and leaving a new event loop (e.g., by opening a modal dialog) will not perform the deferred deletion; for the object to be deleted, the control must return to the event loop from which deleteLater() was called.

Note: It is safe to call this function more than once; when the first deferred deletion event is delivered, any pending events for the object are removed from the event queue.

See also destroyed() and QPointer.

pub unsafe fn block_signals(&self, b: bool) -> bool

If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it). If block is false, no such blocking will occur.

Calls C++ function: bool QObject::blockSignals(bool b).

C++ documentation:

If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it). If block is false, no such blocking will occur.

The return value is the previous value of signalsBlocked().

Note that the destroyed() signal will be emitted even if the signals for this object have been blocked.

Signals emitted while being blocked are not buffered.

See also signalsBlocked() and QSignalBlocker.

pub unsafe fn children(&self) -> Ref<QListOfQObject>

Returns a list of child objects. The QObjectList class is defined in the <QObject> header file as the following:

Calls C++ function: const QList<QObject*>& QObject::children() const.

C++ documentation:

Returns a list of child objects. The QObjectList class is defined in the <QObject> header file as the following:

  typedef QList<QObject*> QObjectList;

The first child added is the first object in the list and the last child added is the last object in the list, i.e. new children are appended at the end.

Note that the list order changes when QWidget children are raised or lowered. A widget that is raised becomes the last object in the list, and a widget that is lowered becomes the first object in the list.

See also findChild(), findChildren(), parent(), and setParent().

pub unsafe fn delete_later(&self)

Schedules this object for deletion.

Calls C++ function: [slot] void QObject::deleteLater().

C++ documentation:

Schedules this object for deletion.

The object will be deleted when control returns to the event loop. If the event loop is not running when this function is called (e.g. deleteLater() is called on an object before QCoreApplication::exec()), the object will be deleted once the event loop is started. If deleteLater() is called after the main event loop has stopped, the object will not be deleted. Since Qt 4.8, if deleteLater() is called on an object that lives in a thread with no running event loop, the object will be destroyed when the thread finishes.

Note that entering and leaving a new event loop (e.g., by opening a modal dialog) will not perform the deferred deletion; for the object to be deleted, the control must return to the event loop from which deleteLater() was called.

Note: It is safe to call this function more than once; when the first deferred deletion event is delivered, any pending events for the object are removed from the event queue.

See also destroyed() and QPointer.

pub unsafe fn disconnect_char_q_object_char( &self, signal: *const c_char, receiver: impl CastInto<Ptr<QObject>>, member: *const c_char ) -> bool

This function overloads disconnect().

Calls C++ function: bool QObject::disconnect(const char* signal = …, const QObject* receiver = …, const char* member = …) const.

C++ documentation:

This function overloads disconnect().

Disconnects signal from method of receiver.

A signal-slot connection is removed when either of the objects involved are destroyed.

Note: This function is thread-safe.

pub unsafe fn disconnect_q_object_char( &self, receiver: impl CastInto<Ptr<QObject>>, member: *const c_char ) -> bool

This function overloads disconnect().

Calls C++ function: bool QObject::disconnect(const QObject* receiver, const char* member = …) const.

C++ documentation:

This function overloads disconnect().

Disconnects all signals in this object from receiver's method.

A signal-slot connection is removed when either of the objects involved are destroyed.

pub unsafe fn disconnect_char_q_object( &self, signal: *const c_char, receiver: impl CastInto<Ptr<QObject>> ) -> bool

This function overloads disconnect().

Calls C++ function: bool QObject::disconnect(const char* signal = …, const QObject* receiver = …) const.

C++ documentation:

This function overloads disconnect().

Disconnects signal from method of receiver.

A signal-slot connection is removed when either of the objects involved are destroyed.

Note: This function is thread-safe.

pub unsafe fn disconnect_char(&self, signal: *const c_char) -> bool

This function overloads disconnect().

Calls C++ function: bool QObject::disconnect(const char* signal = …) const.

C++ documentation:

This function overloads disconnect().

Disconnects signal from method of receiver.

A signal-slot connection is removed when either of the objects involved are destroyed.

Note: This function is thread-safe.

pub unsafe fn disconnect(&self) -> bool

This function overloads disconnect().

Calls C++ function: bool QObject::disconnect() const.

C++ documentation:

This function overloads disconnect().

Disconnects signal from method of receiver.

A signal-slot connection is removed when either of the objects involved are destroyed.

Note: This function is thread-safe.

pub unsafe fn disconnect_q_object( &self, receiver: impl CastInto<Ptr<QObject>> ) -> bool

This function overloads disconnect().

Calls C++ function: bool QObject::disconnect(const QObject* receiver) const.

C++ documentation:

This function overloads disconnect().

Disconnects all signals in this object from receiver's method.

A signal-slot connection is removed when either of the objects involved are destroyed.

pub unsafe fn dump_object_info_mut(&self)

Dumps information about signal connections, etc. for this object to the debug output.

Calls C++ function: void QObject::dumpObjectInfo().

C++ documentation:

Dumps information about signal connections, etc. for this object to the debug output.

Note: before Qt 5.9, this function was not const.

See also dumpObjectTree().

pub unsafe fn dump_object_info(&self)

Dumps information about signal connections, etc. for this object to the debug output.

Calls C++ function: void QObject::dumpObjectInfo() const.

C++ documentation:

Dumps information about signal connections, etc. for this object to the debug output.

Note: before Qt 5.9, this function was not const.

See also dumpObjectTree().

pub unsafe fn dump_object_tree_mut(&self)

Dumps a tree of children to the debug output.

Calls C++ function: void QObject::dumpObjectTree().

C++ documentation:

Dumps a tree of children to the debug output.

Note: before Qt 5.9, this function was not const.

See also dumpObjectInfo().

pub unsafe fn dump_object_tree(&self)

Dumps a tree of children to the debug output.

Calls C++ function: void QObject::dumpObjectTree() const.

C++ documentation:

Dumps a tree of children to the debug output.

Note: before Qt 5.9, this function was not const.

See also dumpObjectInfo().

pub unsafe fn dynamic_property_names(&self) -> CppBox<QListOfQByteArray>

Returns the names of all properties that were dynamically added to the object using setProperty().

Calls C++ function: QList<QByteArray> QObject::dynamicPropertyNames() const.

C++ documentation:

Returns the names of all properties that were dynamically added to the object using setProperty().

This function was introduced in Qt 4.2.

pub unsafe fn eq(&self, p: impl CastInto<Ref<QPointerOfQObject>>) -> bool

Returns true if c1 and c2 are the same Unicode character; otherwise returns false.

Calls C++ function: bool operator==(QObject* o, const QPointer<QObject>& p).

Warning: no exact match found in C++ documentation. Below is the C++ documentation for bool operator==(QChar c1, QChar c2):

Returns true if c1 and c2 are the same Unicode character; otherwise returns false.

pub unsafe fn event(&self, event: impl CastInto<Ptr<QEvent>>) -> bool

This virtual function receives events to an object and should return true if the event e was recognized and processed.

Calls C++ function: virtual bool QObject::event(QEvent* event).

C++ documentation:

This virtual function receives events to an object and should return true if the event e was recognized and processed.

The event() function can be reimplemented to customize the behavior of an object.

Make sure you call the parent event class implementation for all the events you did not handle.

Example:

class MyClass : public QWidget
{
      Q_OBJECT
public:
      MyClass(QWidget *parent = 0);
      ~MyClass();
      bool event(QEvent* ev)
      {
          if (ev->type() == QEvent::PolishRequest) {
              // overwrite handling of PolishRequest if any
              doThings();
              return true;
          } else  if (ev->type() == QEvent::Show) {
              // complement handling of Show if any
              doThings2();
              QWidget::event(ev);
              return true;
          }
          // Make sure the rest of events are handled
          return QWidget::event(ev);
      }
};

See also installEventFilter(), timerEvent(), QCoreApplication::sendEvent(), and QCoreApplication::postEvent().

pub unsafe fn event_filter( &self, watched: impl CastInto<Ptr<QObject>>, event: impl CastInto<Ptr<QEvent>> ) -> bool

Filters events if this object has been installed as an event filter for the watched object.

Calls C++ function: virtual bool QObject::eventFilter(QObject* watched, QEvent* event).

C++ documentation:

Filters events if this object has been installed as an event filter for the watched object.

In your reimplementation of this function, if you want to filter the event out, i.e. stop it being handled further, return true; otherwise return false.

Example:

class MainWindow : public QMainWindow
{
public:
      MainWindow();
protected:
      bool eventFilter(QObject obj, QEvent ev);
private:
      QTextEdit *textEdit;
};
MainWindow::MainWindow()
{
      textEdit = new QTextEdit;
      setCentralWidget(textEdit);
      textEdit->installEventFilter(this);
}
bool MainWindow::eventFilter(QObject obj, QEvent event)
{
      if (obj == textEdit) {
          if (event->type() == QEvent::KeyPress) {
              QKeyEvent keyEvent = static_cast<QKeyEvent>(event);
              qDebug() << “Ate key press” << keyEvent->key();
              return true;
          } else {
              return false;
          }
      } else {
          // pass the event on to the parent class
          return QMainWindow::eventFilter(obj, event);
      }
}

Notice in the example above that unhandled events are passed to the base class's eventFilter() function, since the base class might have reimplemented eventFilter() for its own internal purposes.

Warning: If you delete the receiver object in this function, be sure to return true. Otherwise, Qt will forward the event to the deleted object and the program might crash.

See also installEventFilter().

pub unsafe fn find_child_q_object_2a( &self, a_name: impl CastInto<Ref<QString>>, options: QFlags<FindChildOption> ) -> QPtr<QObject>

Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

Calls C++ function: QObject* QObject::findChild<QObject*>(const QString& aName = …, QFlags<Qt::FindChildOption> options = …) const.

C++ documentation:

Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

If there is more than one child matching the search, the most direct ancestor is returned. If there are several direct ancestors, it is undefined which one will be returned. In that case, findChildren() should be used.

This example returns a child QPushButton of parentWidget named "button1", even if the button isn't a direct child of the parent:

QPushButton button = parentWidget->findChild<QPushButton >(“button1”);

This example returns a QListWidget child of parentWidget:

QListWidget list = parentWidget->findChild<QListWidget >();

This example returns a child QPushButton of parentWidget (its direct parent) named "button1":

QPushButton button = parentWidget->findChild<QPushButton >(“button1”, Qt::FindDirectChildrenOnly);

This example returns a QListWidget child of parentWidget, its direct parent:

QListWidget list = parentWidget->findChild<QListWidget >(QString(), Qt::FindDirectChildrenOnly);

See also findChildren().

pub unsafe fn find_child_q_object_1a( &self, a_name: impl CastInto<Ref<QString>> ) -> QPtr<QObject>

Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

Calls C++ function: QObject* QObject::findChild<QObject*>(const QString& aName = …) const.

C++ documentation:

Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

If there is more than one child matching the search, the most direct ancestor is returned. If there are several direct ancestors, it is undefined which one will be returned. In that case, findChildren() should be used.

This example returns a child QPushButton of parentWidget named "button1", even if the button isn't a direct child of the parent:

QPushButton button = parentWidget->findChild<QPushButton >(“button1”);

This example returns a QListWidget child of parentWidget:

QListWidget list = parentWidget->findChild<QListWidget >();

This example returns a child QPushButton of parentWidget (its direct parent) named "button1":

QPushButton button = parentWidget->findChild<QPushButton >(“button1”, Qt::FindDirectChildrenOnly);

This example returns a QListWidget child of parentWidget, its direct parent:

QListWidget list = parentWidget->findChild<QListWidget >(QString(), Qt::FindDirectChildrenOnly);

See also findChildren().

pub unsafe fn find_child_q_object_0a(&self) -> QPtr<QObject>

Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

Calls C++ function: QObject* QObject::findChild<QObject*>() const.

C++ documentation:

Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

If there is more than one child matching the search, the most direct ancestor is returned. If there are several direct ancestors, it is undefined which one will be returned. In that case, findChildren() should be used.

This example returns a child QPushButton of parentWidget named "button1", even if the button isn't a direct child of the parent:

QPushButton button = parentWidget->findChild<QPushButton >(“button1”);

This example returns a QListWidget child of parentWidget:

QListWidget list = parentWidget->findChild<QListWidget >();

This example returns a child QPushButton of parentWidget (its direct parent) named "button1":

QPushButton button = parentWidget->findChild<QPushButton >(“button1”, Qt::FindDirectChildrenOnly);

This example returns a QListWidget child of parentWidget, its direct parent:

QListWidget list = parentWidget->findChild<QListWidget >(QString(), Qt::FindDirectChildrenOnly);

See also findChildren().

pub unsafe fn find_children_q_object_q_string_q_flags_find_child_option( &self, a_name: impl CastInto<Ref<QString>>, options: QFlags<FindChildOption> ) -> CppBox<QListOfQObject>

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. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QString& aName = …, QFlags<Qt::FindChildOption> options = …) const.

C++ documentation:

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. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

The following example shows how to find a list of child QWidgets of the specified parentWidget named widgetname:

QList<QWidget > widgets = parentWidget.findChildren<QWidget >(“widgetname”);

This example returns all QPushButtons that are children of parentWidget:

QList<QPushButton > allPButtons = parentWidget.findChildren<QPushButton >();

This example returns all QPushButtons that are immediate children of parentWidget:

QList<QPushButton > childButtons = parentWidget.findChildren<QPushButton >(QString(), Qt::FindDirectChildrenOnly);

See also findChild().

pub unsafe fn find_children_q_object_q_reg_exp_q_flags_find_child_option( &self, re: impl CastInto<Ref<QRegExp>>, options: QFlags<FindChildOption> ) -> CppBox<QListOfQObject>

This function overloads findChildren().

Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QRegExp& re, QFlags<Qt::FindChildOption> options = …) const.

C++ documentation:

This function overloads findChildren().

Returns the children of this object that can be cast to type T and that have names matching the regular expression regExp, or an empty list if there are no such objects. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

pub unsafe fn find_children_q_object_q_regular_expression_q_flags_find_child_option( &self, re: impl CastInto<Ref<QRegularExpression>>, options: QFlags<FindChildOption> ) -> CppBox<QListOfQObject>

This function overloads findChildren().

Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QRegularExpression& re, QFlags<Qt::FindChildOption> options = …) const.

C++ documentation:

This function overloads findChildren().

Returns the children of this object that can be cast to type T and that have names matching the regular expression re, or an empty list if there are no such objects. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

This function was introduced in Qt 5.0.

pub unsafe fn find_children_q_object_q_string( &self, a_name: impl CastInto<Ref<QString>> ) -> CppBox<QListOfQObject>

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. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QString& aName = …) const.

C++ documentation:

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. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

The following example shows how to find a list of child QWidgets of the specified parentWidget named widgetname:

QList<QWidget > widgets = parentWidget.findChildren<QWidget >(“widgetname”);

This example returns all QPushButtons that are children of parentWidget:

QList<QPushButton > allPButtons = parentWidget.findChildren<QPushButton >();

This example returns all QPushButtons that are immediate children of parentWidget:

QList<QPushButton > childButtons = parentWidget.findChildren<QPushButton >(QString(), Qt::FindDirectChildrenOnly);

See also findChild().

pub unsafe fn find_children_q_object(&self) -> CppBox<QListOfQObject>

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. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>() const.

C++ documentation:

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. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

The following example shows how to find a list of child QWidgets of the specified parentWidget named widgetname:

QList<QWidget > widgets = parentWidget.findChildren<QWidget >(“widgetname”);

This example returns all QPushButtons that are children of parentWidget:

QList<QPushButton > allPButtons = parentWidget.findChildren<QPushButton >();

This example returns all QPushButtons that are immediate children of parentWidget:

QList<QPushButton > childButtons = parentWidget.findChildren<QPushButton >(QString(), Qt::FindDirectChildrenOnly);

See also findChild().

pub unsafe fn find_children_q_object_q_reg_exp( &self, re: impl CastInto<Ref<QRegExp>> ) -> CppBox<QListOfQObject>

This function overloads findChildren().

Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QRegExp& re) const.

C++ documentation:

This function overloads findChildren().

Returns the children of this object that can be cast to type T and that have names matching the regular expression regExp, or an empty list if there are no such objects. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

pub unsafe fn find_children_q_object_q_regular_expression( &self, re: impl CastInto<Ref<QRegularExpression>> ) -> CppBox<QListOfQObject>

This function overloads findChildren().

Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QRegularExpression& re) const.

C++ documentation:

This function overloads findChildren().

Returns the children of this object that can be cast to type T and that have names matching the regular expression re, or an empty list if there are no such objects. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

This function was introduced in Qt 5.0.

pub unsafe fn inherits(&self, classname: *const c_char) -> bool

Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false.

Calls C++ function: bool QObject::inherits(const char* classname) const.

C++ documentation:

Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false.

A class is considered to inherit itself.

Example:

QTimer *timer = new QTimer;         // QTimer inherits QObject
timer->inherits(“QTimer”);          // returns true
timer->inherits(“QObject”);         // returns true
timer->inherits(“QAbstractButton”); // returns false
// QVBoxLayout inherits QObject and QLayoutItem
QVBoxLayout *layout = new QVBoxLayout;
layout->inherits(“QObject”);        // returns true
layout->inherits(“QLayoutItem”);    // returns true (even though QLayoutItem is not a QObject)

If you need to determine whether an object is an instance of a particular class for the purpose of casting it, consider using qobject_cast<Type *>(object) instead.

See also metaObject() and qobject_cast().

pub unsafe fn install_event_filter( &self, filter_obj: impl CastInto<Ptr<QObject>> )

Installs an event filter filterObj on this object. For example:

Calls C++ function: void QObject::installEventFilter(QObject* filterObj).

C++ documentation:

Installs an event filter filterObj on this object. For example:

  monitoredObj->installEventFilter(filterObj);

An event filter is an object that receives all events that are sent to this object. The filter can either stop the event or forward it to this object. The event filter filterObj receives events via its eventFilter() function. The eventFilter() function must return true if the event should be filtered, (i.e. stopped); otherwise it must return false.

If multiple event filters are installed on a single object, the filter that was installed last is activated first.

Here's a KeyPressEater class that eats the key presses of its monitored objects:

class KeyPressEater : public QObject
{
      Q_OBJECT
      ...
protected:
      bool eventFilter(QObject obj, QEvent event);
};
bool KeyPressEater::eventFilter(QObject obj, QEvent event)
{
      if (event->type() == QEvent::KeyPress) {
          QKeyEvent keyEvent = static_cast<QKeyEvent >(event);
          qDebug(“Ate key press %d”, keyEvent->key());
          return true;
      } else {
          // standard event processing
          return QObject::eventFilter(obj, event);
      }
}

And here's how to install it on two widgets:

KeyPressEater keyPressEater = new KeyPressEater(this);
QPushButton pushButton = new QPushButton(this);
QListView *listView = new QListView(this);
pushButton->installEventFilter(keyPressEater);
listView->installEventFilter(keyPressEater);

The QShortcut class, for example, uses this technique to intercept shortcut key presses.

Warning: If you delete the receiver object in your eventFilter() function, be sure to return true. If you return false, Qt sends the event to the deleted object and the program will crash.

Note that the filtering object must be in the same thread as this object. If filterObj is in a different thread, this function does nothing. If either filterObj or this object are moved to a different thread after calling this function, the event filter will not be called until both objects have the same thread affinity again (it is not removed).

See also removeEventFilter(), eventFilter(), and event().

pub unsafe fn is_widget_type(&self) -> bool

Returns true if the object is a widget; otherwise returns false.

Calls C++ function: bool QObject::isWidgetType() const.

C++ documentation:

Returns true if the object is a widget; otherwise returns false.

Calling this function is equivalent to calling inherits("QWidget"), except that it is much faster.

pub unsafe fn is_window_type(&self) -> bool

Returns true if the object is a window; otherwise returns false.

Calls C++ function: bool QObject::isWindowType() const.

C++ documentation:

Returns true if the object is a window; otherwise returns false.

Calling this function is equivalent to calling inherits("QWindow"), except that it is much faster.

pub unsafe fn kill_timer(&self, id: c_int)

Kills the timer with timer identifier, id.

Calls C++ function: void QObject::killTimer(int id).

C++ documentation:

Kills the timer with timer identifier, id.

The timer identifier is returned by startTimer() when a timer event is started.

See also timerEvent() and startTimer().

pub unsafe fn meta_object(&self) -> Ptr<QMetaObject>

Returns a pointer to the meta-object of this object.

Calls C++ function: virtual const QMetaObject* QObject::metaObject() const.

C++ documentation:

Returns a pointer to the meta-object of this object.

A meta-object contains information about a class that inherits QObject, e.g. class name, superclass name, properties, signals and slots. Every QObject subclass that contains the Q_OBJECT macro will have a meta-object.

The meta-object information is required by the signal/slot connection mechanism and the property system. The inherits() function also makes use of the meta-object.

If you have no pointer to an actual object instance but still want to access the meta-object of a class, you can use staticMetaObject.

Example:

QObject *obj = new QPushButton;
obj->metaObject()->className();             // returns “QPushButton”
QPushButton::staticMetaObject.className();  // returns “QPushButton”

See also staticMetaObject.

pub unsafe fn move_to_thread(&self, thread: impl CastInto<Ptr<QThread>>)

Changes the thread affinity for this object and its children. The object cannot be moved if it has a parent. Event processing will continue in the targetThread.

Calls C++ function: void QObject::moveToThread(QThread* thread).

C++ documentation:

Changes the thread affinity for this object and its children. The object cannot be moved if it has a parent. Event processing will continue in the targetThread.

To move an object to the main thread, use QApplication::instance() to retrieve a pointer to the current application, and then use QApplication::thread() to retrieve the thread in which the application lives. For example:

myObject->moveToThread(QApplication::instance()->thread());

If targetThread is zero, all event processing for this object and its children stops.

Note that all active timers for the object will be reset. The timers are first stopped in the current thread and restarted (with the same interval) in the targetThread. As a result, constantly moving an object between threads can postpone timer events indefinitely.

A QEvent::ThreadChange event is sent to this object just before the thread affinity is changed. You can handle this event to perform any special processing. Note that any new events that are posted to this object will be handled in the targetThread.

Warning: This function is not thread-safe; the current thread must be same as the current thread affinity. In other words, this function can only "push" an object from the current thread to another thread, it cannot "pull" an object from any arbitrary thread to the current thread.

See also thread().

pub unsafe fn object_name(&self) -> CppBox<QString>

This property holds the name of this object

Calls C++ function: QString QObject::objectName() const.

C++ documentation:

This property holds the name of this object

You can find an object by name (and type) using findChild(). You can find a set of objects with findChildren().

qDebug(“MyClass::setPrecision(): (%s) invalid precision %f”,
         qPrintable(objectName()), newPrecision);

By default, this property contains an empty string.

Access functions:

QString	objectName() const
void	setObjectName(const QString &name)

Notifier signal:

void

objectNameChanged(const QString &objectName)

[see note below]

Note: This is a private signal. It can be used in signal connections but cannot be emitted by the user.

See also metaObject() and QMetaObject::className().

pub unsafe fn parent(&self) -> QPtr<QObject>

Returns a pointer to the parent object.

Calls C++ function: QObject* QObject::parent() const.

C++ documentation:

Returns a pointer to the parent object.

See also setParent() and children().

pub unsafe fn property(&self, name: *const c_char) -> CppBox<QVariant>

Returns the value of the object's name property.

Calls C++ function: QVariant QObject::property(const char* name) const.

C++ documentation:

Returns the value of the object’s name property.

If no such property exists, the returned variant is invalid.

Information about all available properties is provided through the metaObject() and dynamicPropertyNames().

See also setProperty(), QVariant::isValid(), metaObject(), and dynamicPropertyNames().

pub unsafe fn qt_metacall( &self, arg1: Call, arg2: c_int, arg3: *mut *mut c_void ) -> c_int

Calls C++ function: virtual int QObject::qt_metacall(QMetaObject::Call arg1, int arg2, void** arg3).

pub unsafe fn qt_metacast(&self, arg1: *const c_char) -> *mut c_void

Calls C++ function: virtual void* QObject::qt_metacast(const char* arg1).

pub unsafe fn remove_event_filter(&self, obj: impl CastInto<Ptr<QObject>>)

Removes an event filter object obj from this object. The request is ignored if such an event filter has not been installed.

Calls C++ function: void QObject::removeEventFilter(QObject* obj).

C++ documentation:

Removes an event filter object obj from this object. The request is ignored if such an event filter has not been installed.

All event filters for this object are automatically removed when this object is destroyed.

It is always safe to remove an event filter, even during event filter activation (i.e. from the eventFilter() function).

See also installEventFilter(), eventFilter(), and event().

pub unsafe fn set_object_name(&self, name: impl CastInto<Ref<QString>>)

This property holds the name of this object

Calls C++ function: void QObject::setObjectName(const QString& name).

C++ documentation:

This property holds the name of this object

You can find an object by name (and type) using findChild(). You can find a set of objects with findChildren().

qDebug(“MyClass::setPrecision(): (%s) invalid precision %f”,
         qPrintable(objectName()), newPrecision);

By default, this property contains an empty string.

Access functions:

QString	objectName() const
void	setObjectName(const QString &name)

Notifier signal:

void

objectNameChanged(const QString &objectName)

[see note below]

Note: This is a private signal. It can be used in signal connections but cannot be emitted by the user.

See also metaObject() and QMetaObject::className().

pub unsafe fn set_parent(&self, parent: impl CastInto<Ptr<QObject>>)

Makes the object a child of parent.

Calls C++ function: void QObject::setParent(QObject* parent).

C++ documentation:

Makes the object a child of parent.

See also parent() and children().

pub unsafe fn set_property( &self, name: *const c_char, value: impl CastInto<Ref<QVariant>> ) -> bool

Sets the value of the object's name property to value.

Calls C++ function: bool QObject::setProperty(const char* name, const QVariant& value).

C++ documentation:

Sets the value of the object’s name property to value.

If the property is defined in the class using Q_PROPERTY then true is returned on success and false otherwise. If the property is not defined using Q_PROPERTY, and therefore not listed in the meta-object, it is added as a dynamic property and false is returned.

Information about all available properties is provided through the metaObject() and dynamicPropertyNames().

Dynamic properties can be queried again using property() and can be removed by setting the property value to an invalid QVariant. Changing the value of a dynamic property causes a QDynamicPropertyChangeEvent to be sent to the object.

Note: Dynamic properties starting with "_q_" are reserved for internal purposes.

See also property(), metaObject(), dynamicPropertyNames(), and QMetaProperty::write().

pub unsafe fn signals_blocked(&self) -> bool

Returns true if signals are blocked; otherwise returns false.

Calls C++ function: bool QObject::signalsBlocked() const.

C++ documentation:

Returns true if signals are blocked; otherwise returns false.

Signals are not blocked by default.

See also blockSignals() and QSignalBlocker.

pub unsafe fn start_timer_2a( &self, interval: c_int, timer_type: TimerType ) -> c_int

Starts a timer and returns a timer identifier, or returns zero if it could not start a timer.

Calls C++ function: int QObject::startTimer(int interval, Qt::TimerType timerType = …).

C++ documentation:

Starts a timer and returns a timer identifier, or returns zero if it could not start a timer.

A timer event will occur every interval milliseconds until killTimer() is called. If interval is 0, then the timer event occurs once every time there are no more window system events to process.

The virtual timerEvent() function is called with the QTimerEvent event parameter class when a timer event occurs. Reimplement this function to get timer events.

If multiple timers are running, the QTimerEvent::timerId() can be used to find out which timer was activated.

Example:

class MyObject : public QObject
{
      Q_OBJECT
public:
      MyObject(QObject *parent = 0);
protected:
      void timerEvent(QTimerEvent *event);
};
MyObject::MyObject(QObject *parent)
      : QObject(parent)
{
      startTimer(50);     // 50-millisecond timer
      startTimer(1000);   // 1-second timer
      startTimer(60000);  // 1-minute timer
      using namespace std::chrono;
      startTimer(milliseconds(50));
      startTimer(seconds(1));
      startTimer(minutes(1));
      // since C++14 we can use std::chrono::duration literals, e.g.:
      startTimer(100ms);
      startTimer(5s);
      startTimer(2min);
      startTimer(1h);
}
void MyObject::timerEvent(QTimerEvent *event)
{
      qDebug() << “Timer ID:” << event->timerId();
}

Note that QTimer's accuracy depends on the underlying operating system and hardware. The timerType argument allows you to customize the accuracy of the timer. See Qt::TimerType for information on the different timer types. Most platforms support an accuracy of 20 milliseconds; some provide more. If Qt is unable to deliver the requested number of timer events, it will silently discard some.

The QTimer class provides a high-level programming interface with single-shot timers and timer signals instead of events. There is also a QBasicTimer class that is more lightweight than QTimer and less clumsy than using timer IDs directly.

See also timerEvent(), killTimer(), and QTimer::singleShot().

pub unsafe fn start_timer_1a(&self, interval: c_int) -> c_int

Starts a timer and returns a timer identifier, or returns zero if it could not start a timer.

Calls C++ function: int QObject::startTimer(int interval).

C++ documentation:

Starts a timer and returns a timer identifier, or returns zero if it could not start a timer.

A timer event will occur every interval milliseconds until killTimer() is called. If interval is 0, then the timer event occurs once every time there are no more window system events to process.

The virtual timerEvent() function is called with the QTimerEvent event parameter class when a timer event occurs. Reimplement this function to get timer events.

If multiple timers are running, the QTimerEvent::timerId() can be used to find out which timer was activated.

Example:

class MyObject : public QObject
{
      Q_OBJECT
public:
      MyObject(QObject *parent = 0);
protected:
      void timerEvent(QTimerEvent *event);
};
MyObject::MyObject(QObject *parent)
      : QObject(parent)
{
      startTimer(50);     // 50-millisecond timer
      startTimer(1000);   // 1-second timer
      startTimer(60000);  // 1-minute timer
      using namespace std::chrono;
      startTimer(milliseconds(50));
      startTimer(seconds(1));
      startTimer(minutes(1));
      // since C++14 we can use std::chrono::duration literals, e.g.:
      startTimer(100ms);
      startTimer(5s);
      startTimer(2min);
      startTimer(1h);
}
void MyObject::timerEvent(QTimerEvent *event)
{
      qDebug() << “Timer ID:” << event->timerId();
}

Note that QTimer's accuracy depends on the underlying operating system and hardware. The timerType argument allows you to customize the accuracy of the timer. See Qt::TimerType for information on the different timer types. Most platforms support an accuracy of 20 milliseconds; some provide more. If Qt is unable to deliver the requested number of timer events, it will silently discard some.

The QTimer class provides a high-level programming interface with single-shot timers and timer signals instead of events. There is also a QBasicTimer class that is more lightweight than QTimer and less clumsy than using timer IDs directly.

See also timerEvent(), killTimer(), and QTimer::singleShot().

pub unsafe fn thread(&self) -> QPtr<QThread>

Returns the thread in which the object lives.

Calls C++ function: QThread* QObject::thread() const.

C++ documentation:

Returns the thread in which the object lives.

See also moveToThread().

Trait Implementations

impl CppDeletable for QThreadPool

unsafe fn delete(&self)

Destroys the QThreadPool. This function will block until all runnables have been completed.

Calls C++ function: virtual [destructor] void QThreadPool::~QThreadPool().

C++ documentation:

Destroys the QThreadPool. This function will block until all runnables have been completed.

impl Deref for QThreadPool

fn deref(&self) -> &QObject

Calls C++ function: QObject* static_cast<QObject*>(QThreadPool* ptr).

type Target = QObject

The resulting type after dereferencing.

impl DynamicCast<QThreadPool> for QObject

unsafe fn dynamic_cast(ptr: Ptr<QObject>) -> Ptr<QThreadPool>

Calls C++ function: QThreadPool* dynamic_cast<QThreadPool*>(QObject* ptr).

impl StaticDowncast<QThreadPool> for QObject

unsafe fn static_downcast(ptr: Ptr<QObject>) -> Ptr<QThreadPool>

Calls C++ function: QThreadPool* static_cast<QThreadPool*>(QObject* ptr).

impl StaticUpcast<QObject> for QThreadPool

unsafe fn static_upcast(ptr: Ptr<QThreadPool>) -> Ptr<QObject>

Calls C++ function: QObject* static_cast<QObject*>(QThreadPool* ptr).