QRunnable Class Reference

\inmodule QtCore More...

#include <qrunnable.h>

Inheritance diagram for QRunnable:

Collaboration diagram for QRunnable:

Public Types
template<typename Callable >
using	if_callable = std::enable_if_t< std::is_invocable_r_v< void, Callable >, bool >

Public Member Functions
virtual void	run ()=0
	Implement this pure virtual function in your subclass.
constexpr	QRunnable () noexcept=default
	Constructs a QRunnable.
virtual	~QRunnable ()
	QRunnable virtual destructor.
bool	autoDelete () const
	Returns true is auto-deletion is enabled; false otherwise.
void	setAutoDelete (bool autoDelete)
	Enables auto-deletion if autoDelete is true; otherwise auto-deletion is disabled.
template<typename Callable , if_callable< Callable > = true>
	QGenericRunnable (Callable &&c)
	~QGenericRunnable () override
void	run () override

Static Public Member Functions
template<typename Callable , if_callable< Callable > = true>
static QRunnable *	create (Callable &&functionToRun)
static QRunnable *	create (std::nullptr_t)=delete

Detailed Description

\inmodule QtCore

Since

4.4

The QRunnable class is the base class for all runnable objects.

The QRunnable class is an interface for representing a task or piece of code that needs to be executed, represented by your reimplementation of the run() function.

You can use QThreadPool to execute your code in a separate thread. QThreadPool deletes the QRunnable automatically if autoDelete() returns true (the default). Use setAutoDelete() to change the auto-deletion flag.

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

See also

QThreadPool

Definition at line 17 of file qrunnable.h.

Member Typedef Documentation

if_callable

template<typename Callable >

using QRunnable::if_callable = std::enable_if_t<std::is_invocable_r_v<void, Callable>, bool>

Definition at line 31 of file qrunnable.h.

Constructor & Destructor Documentation

QRunnable()

QRunnable::QRunnable ( )

constexprdefaultnoexcept

Constructs a QRunnable.

Auto-deletion is enabled by default.

See also

autoDelete(), setAutoDelete()

~QRunnable()

QRunnable::~QRunnable ( )

virtual

QRunnable virtual destructor.

Definition at line 10 of file qrunnable.cpp.

~QGenericRunnable()

QRunnable::~QGenericRunnable ( )

override

Member Function Documentation

autoDelete()

bool QRunnable::autoDelete ( ) const

inline

Returns true is auto-deletion is enabled; false otherwise.

If auto-deletion is enabled, QThreadPool will automatically delete this runnable after calling run(); otherwise, ownership remains with the application programmer.

See also

setAutoDelete(), QThreadPool

Definition at line 37 of file qrunnable.h.

Referenced by QThreadPoolThread::run(), and QThreadPoolPrivate::stealAndRunRunnable().

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create() [1/2]

template<typename Callable , QRunnable::if_callable< Callable > >

QRunnable * QRunnable::create ( Callable &&  functionToRun )

static

Definition at line 114 of file qrunnable.h.

References QGenericRunnable().

Referenced by QThreadPool::start(), QThreadPool::startOnReservedThread(), and QThreadPool::tryStart().

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create() [2/2]

static QRunnable * QRunnable::create ( std::nullptr_t  )

staticdelete

QGenericRunnable()

template<typename Callable , if_callable< Callable > = true>

QRunnable::QGenericRunnable ( Callable &&  c )

inlineexplicit

Definition at line 90 of file qrunnable.h.

Referenced by create().

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run() [1/2]

void QRunnable::run ( )

override

run() [2/2]

QRunnable::run ( )

pure virtual

Implement this pure virtual function in your subclass.

Implemented in QtConcurrent::RunFunctionTaskBase< T >, QtConcurrent::RunFunctionTaskBase< InvokeResultType< Function, Args... > >, QtConcurrent::RunFunctionTaskBase< PromiseType >, QtConcurrent::ThreadEngineBase, HelloWorldTask, QtPrivate::AsyncContinuation< Function, ResultType, ParentResultType >, QDnsLookupRunnable, QHostInfoRunnable, QQmlXmlListModelQueryRunnable, QQuickShaderEffectSourceCleanup, QQuickWindowQObjectCleanupJob, QQuickShapeFillRunnable, QQuickShapeStrokeRunnable, QGeoCodeJsonParser, QGeoRouteXmlParser, and CleanupJob.

Referenced by QSGRenderThread::event(), QSGSoftwareRenderThread::event(), QSGRenderLoop::postJob(), and QThreadPoolPrivate::stealAndRunRunnable().

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setAutoDelete()

bool QRunnable::setAutoDelete ( bool  autoDelete )

inline

Enables auto-deletion if autoDelete is true; otherwise auto-deletion is disabled.

If auto-deletion is enabled, QThreadPool will automatically delete this runnable after calling run(); otherwise, ownership remains with the application programmer.

Note that this flag must be set before calling QThreadPool::start(). Calling this function after QThreadPool::start() results in undefined behavior.

See also

autoDelete(), QThreadPool

Definition at line 38 of file qrunnable.h.

Referenced by QHostInfoRunnable::QHostInfoRunnable(), QQmlXmlListModelQueryRunnable::QQmlXmlListModelQueryRunnable(), QtConcurrent::ThreadEngineBase::ThreadEngineBase(), and QQuickShapeGenericRenderer::endSync().

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

• qtbase/src/corelib/thread/qrunnable.h
• qtbase/src/corelib/thread/qrunnable.cpp