> ## Documentation Index
> Fetch the complete documentation index at: https://devdocs.xbox.com/llms.txt
> Use this file to discover all available pages before exploring further.

# 如何：使用事件控制手动队列分派

> 如何：使用事件控制手动队列分派

## 示例

游戏可能希望将其用于任务队列的线程与游戏中的其他工作共享。以下示例展示了如何使用任务队列在队列中有可分派的项时发出条件变量信号。

```c++ theme={null}
// We use condition variables to signal when there's something for us  
// in the queue and a bool to signal when we want the whole thing to close.  
// Keep all this in a struct for convenient access.  
struct QueueControl  
{  
    std::condition_variable workActivity;  
    std::mutex workMutex;  
    std::condition_variable completionActivity;  
    std::mutex completionMutex;  
    bool terminate = false;  
} queueControl;  
  
void CALLBACK TaskQueueNewItemSubmitted(  
    void* context, XTaskQueueHandle, XTaskQueuePort port)  
{  
    // A new callback has been submitted. Notify the correct condition variable.  
    QueueControl* queueControl = static_cast<QueueControl*>(context);  
    switch (port)  
    {  
    case XTaskQueuePort::Work:  
        queueControl->workActivity.notify_all();  
        break;  
  
    case XTaskQueuePort::Completion:  
        queueControl->completionActivity.notify_all();  
        break;  
    }  
}  
  
void CreatingTaskQueueWithManualSignaling()  
{  
    // Create a manual task queue.  
    XTaskQueueHandle queue;  
    HRESULT hr = XTaskQueueCreate(  
        XTaskQueueDispatchMode::Manual,  
        XTaskQueueDispatchMode::Manual,  
        &queue);  
  
    if (FAILED(hr))  
    {  
        printf("Creating queue failed: 0x%x\r\n", hr);  
        return;  
    }  
  
    // Listen to callback-submitted notifications to signal  
    // our condition variable.  
    XTaskQueueRegistrationToken token;  
    hr = XTaskQueueRegisterMonitor(  
        queue, &queueControl,  
        TaskQueueNewItemSubmitted, &token);  
  
    std::thread workThread([&]()  
    {  
        std::unique_lock<std::mutex> lock(queueControl.workMutex);  
        while (!queueControl.terminate)  
        {  
            queueControl.workActivity.wait(lock);  
            XTaskQueueDispatch(queue, XTaskQueuePort::Work, 0);  
        }  
    });  
  
    std::thread completionThread([&]()  
    {  
        std::unique_lock<std::mutex> lock(queueControl.completionMutex);  
        while (!queueControl.terminate)  
        {  
            queueControl.completionActivity.wait(lock);  
            XTaskQueueDispatch(queue, XTaskQueuePort::Completion, 0);  
        }  
    });  
  
    SubmitCallbacks(queue);  
  
    // Wait a while for the callbacks to run.  
    Sleep(1000);  
  
    XTaskQueueTerminate(queue, true, nullptr, nullptr);  
  
    queueControl.terminate = true; 
    queueControl.workActivity.notify_all(); 
    queueControl.completionActivity.notify_all();  
  
    workThread.join();  
    completionThread.join();  
}  
```

## 另请参阅

[设计任务队列](/build/core-features/common/async/async-task-queue-design)


## Related topics

- [XTaskQueueMonitorCallback](/zh-CN/reference/system/xtaskqueue/functions/xtaskqueuemonitorcallback.md)
- [异步任务队列设计](/zh-CN/build/core-features/common/async/async-task-queue-design.md)
- [在 XSAPI C API 中进行异步调用](/zh-CN/services/xbox-services/fundamentals/xbox-services-api/live-flatc-async-patterns.md)
- [如何：创建手动任务队列](/zh-CN/build/core-features/common/async/async-task-queue-design-howto/creating-manual-task-queue.md)
- [异步编程模型](/zh-CN/build/core-features/common/async/async-programming-model.md)