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How to: Duplicating a task queue handle

Example

If you have long-running work, you might want to duplicate the task queue handle for the duration of the work. In this way, anyone calling XTaskQueueCloseHandle won't close the queue while you still need it. This is shown in the following example.

void DuplicatingTaskQueueHandle() 
{ 
    XTaskQueueHandle queue; 
 
    HRESULT hr = XTaskQueueCreate( 
        XTaskQueueDispatchMode::Manual,  
        XTaskQueueDispatchMode::Manual,  
        &queue); 
 
    if (FAILED(hr)) 
    { 
        printf("Failed to create task queue: 0x%x\r\n", hr); 
        return; 
    } 
 
    class LongRunningWork 
    { 
    public: 
        HRESULT Initialize(XTaskQueueHandle queue) 
        { 
            return XTaskQueueDuplicateHandle(queue, &m_queue); 
        } 
         
        ~LongRunningWork() 
        { 
            if (m_queue != nullptr) 
            { 
                XTaskQueueCloseHandle(m_queue); 
            } 
        } 
 
    private: 
        XTaskQueueHandle m_queue = nullptr; 
    }; 
 
    LongRunningWork work; 
    hr = work.Initialize(queue); 
     
    // Note that the queue handle for LongRunningWork is still valid. 
    XTaskQueueCloseHandle(queue); 
 
    if (FAILED(hr)) 
    { 
        printf("Failed to duplicate queue handle: 0x%x\r\n", hr); 
    } 
} 

See also

Designing the task queue