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# XTaskQueueCreateComposite

> XTaskQueueCreateComposite

# XTaskQueueCreateComposite

Creates a task queue composed of ports of other task queues.

## Syntax

```cpp theme={null}
HRESULT XTaskQueueCreateComposite(  
         XTaskQueuePortHandle workPort,  
         XTaskQueuePortHandle completionPort,  
         XTaskQueueHandle* queue  
)  
```

### Parameters

*workPort*   \_In\_\
Type: XTaskQueuePortHandle

The port to use for queuing work callbacks.

*completionPort*   \_In\_\
Type: XTaskQueuePortHandle

The port to use for queuing completion callbacks.

*queue*   \_Out\_\
Type: XTaskQueueHandle\*

The newly created queue.

### Return value

Type: HRESULT

HRESULT success or error code.

## Remarks

<Note>This function isn't safe to call on a time-sensitive thread. For more information, see [Time-sensitive threads](https://learn.microsoft.com/gaming/gdk/docs/gdk-dev/console-dev/overviews/threads/time-sensitive-threads).</Note>

Task queues are reference counted objects. Release the reference by calling [XTaskQueueCloseHandle](/reference/system/xtaskqueue/functions/xtaskqueueclosehandle).

A task queue has work and completion ports and tasks can be queued to either port. Each port can be configured with its own dispatch mode.

For most scenarios, you create a task queue with the [XTaskQueueCreate](/reference/system/xtaskqueue/functions/xtaskqueuecreate) API. If you are chaining multiple asynchronous calls together, however, sometimes it is useful to create a composite queue via **XTaskQueueCreateComposite**. Consider an API whose implementation needs to invoke another API that uses a task queue. You may want to redirect the completion callback of the API so it doesn't tie up the completion thread of the caller. In this case, you can create a composite task queue whose work and completion ports are built from the work port of another queue.

The following example creates a composite task queue.

```cpp theme={null}
void CreatingCompositeQueue()
{
    XTaskQueueHandle queue;

    HRESULT hr = XTaskQueueCreate(
        XTaskQueueDispatchMode::ThreadPool, 
        XTaskQueueDispatchMode::Manual, 
        &queue);

    if (FAILED(hr))
    {
        printf("failed to create task queue: 0x%x\r\n", hr);
        return;
    }

    XTaskQueuePortHandle workPort;

    // Create a composite queue that uses the work port from
    // another queue for both work and completion ports.

    hr = XTaskQueueGetPort(queue, XTaskQueuePort::Work, &workPort);
    if (FAILED(hr))
    {
        printf("failed to get work port 0x%x\r\n", hr);
        XTaskQueueCloseHandle(queue);
        return;
    }

    XTaskQueueHandle compositeQueue;
    hr = XTaskQueueCreateComposite(workPort, workPort, &compositeQueue);
    if (FAILED(hr))
    {
        printf("failed to create composiute queue 0x%x\r\n", hr);
        XTaskQueueCloseHandle(queue);
        return;
    }

    // Use the queue as needed
    SubmitCallbacks(compositeQueue);

    // Wait a while for the callbacks to run
    Sleep(1000);

    XTaskQueueCloseHandle(compositeQueue);
    XTaskQueueCloseHandle(queue);
}
```

## Requirements

**Header:** XTaskQueue.h

**Library:** xgameruntime.lib

**Supported platforms:** Windows, XBOX One family consoles and XBOX Series consoles

## Conceptual documentation

* [Time-sensitive threads](https://learn.microsoft.com/gaming/gdk/docs/gdk-dev/console-dev/overviews/threads/time-sensitive-threads)

## See also

[XTaskQueue members](/reference/system/xtaskqueue/xtaskqueue_members)\
[Asynchronous Programming Model](/build/core-features/common/async/async-programming-model)\
[Async Task Queue Design](/build/core-features/common/async/async-task-queue-design)


## Related topics

- [XTaskQueueCreate](/reference/system/xtaskqueue/functions/xtaskqueuecreate.md)
- [XTaskQueue](/reference/system/xtaskqueue/xtaskqueue_members.md)
- [Async task queue design](/build/core-features/common/async/async-task-queue-design.md)
- [How to: Creating a composite task queue](/build/core-features/common/async/async-task-queue-design-howto/creating-composite-task-queue.md)
- [Create task queue example](/build/core-features/common/async/async-libraries/async-library-xtaskqueue-example-create-task-queue.md)