HRESULT XTaskQueueGetPort(  
         XTaskQueueHandle queue,  
         XTaskQueuePort port,  
         XTaskQueuePortHandle* portHandle  
)  

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);
}