- Qt 6.9
- Qt Concurrent
- C++ Classes
- QTaskBuilder
- Qt 6.9.3 Reference Documentation

# QtConcurrent::QTaskBuilder Class

template <typename Task, typename... Args> class QtConcurrent::QTaskBuilder

The QTaskBuilder class is used for adjusting task parameters. More...

Header: | `#include <QTaskBuilder>`
CMake: | `find_package(Qt6 REQUIRED COMPONENTS Concurrent)` `target_link_libraries(mytarget PRIVATE Qt6::Concurrent)`
qmake: | `QT += concurrent`
Since: | Qt 6.0

- List of all members, including inherited members

## Public Functions

QtConcurrent::QTaskBuilder<Task, Args...> & | onThreadPool(QThreadPool &newThreadPool)
QFuture<QtConcurrent::InvokeResultType> | spawn()
void | spawn(QtConcurrent::FutureResult)
QtConcurrent::QTaskBuilder<Task, ExtraArgs...> | withArguments(ExtraArgs &&... args)
QtConcurrent::QTaskBuilder<Task, Args...> & | withPriority(int newPriority)

## Related Non-Members

| InvokeResultType

## Detailed Description

It's not possible to create an object of this class manually. See Concurrent Task for more details and usage examples.

## Member Function Documentation

### QtConcurrent::QTaskBuilder<Task, Args...> &QTaskBuilder::onThreadPool(QThreadPool &newThreadPool)

Sets the thread pool newThreadPool that the task will be invoked on.

### QFuture<QtConcurrent::InvokeResultType> QTaskBuilder::spawn()

Runs the task in a separate thread and returns a future object immediately. This is a non-blocking call. The task might not start immediately.

### void QTaskBuilder::spawn(QtConcurrent::FutureResult)

Runs the task in a separate thread. This is a non-blocking call. The task might not start immediately.

### template <typename... ExtraArgs> QtConcurrent::QTaskBuilder<Task, ExtraArgs...> QTaskBuilder::withArguments(ExtraArgs &&... args)

Sets the arguments args the task will be invoked with. The code is ill-formed (causes compilation errors) if:

- This function is invoked more than once.
- The arguments count is zero.

### QtConcurrent::QTaskBuilder<Task, Args...> &QTaskBuilder::withPriority(int newPriority)

Sets the priority newPriority that the task will be invoked with.

## Related Non-Members

### `[alias]` InvokeResultType

The simplified definition of this type looks like this:

     template <class Task, class ...Args>
     using InvokeResultType = std::invoke_result_t<std::decay_t<Task>, std::decay_t<Args>...>;

The real implementation also contains a compile-time check for whether the task can be invoked with the specified arguments or not.