> ## 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：提交回调

> 如何：提交回调

## 示例

以下示例展示了如何将回调提交到任务队列的工作端口或完成端口。首先，它提交一个工作回调。然后，在工作回调的末尾，它再提交一个完成回调。这是典型的用法。为简洁起见，`SubmitCallbacks` 函数在后续的场景中被复用。

```c++ theme={null}
void CALLBACK SampleCompletionCallback(void*, bool cancel)
{
    printf("Completion invoked on thread %d. Cancel? %d.\r\n",
    GetCurrentThreadId(), cancel);
}

void CALLBACK SampleWorkCallback(void* context, bool cancel)
{
    printf("Worker invoked on thread %d. Cancel? %d.\r\n",
    GetCurrentThreadId(), cancel);

    XTaskQueueHandle queueFromContext = static_cast<XTaskQueueHandle>(context);

    HRESULT hrCompletion = XTaskQueueSubmitCallback(
        queueFromContext,
        XTaskQueuePort::Completion,
        nullptr,
        SampleCompletionCallback);

    if (FAILED(hrCompletion))
    {
        printf("Error 0x%x submitting completion.\r\n", hrCompletion);
    }
}

void SubmitCallbacks(XTaskQueueHandle queue)
{
    HRESULT hrWork = XTaskQueueSubmitCallback(
        queue,
        XTaskQueuePort::Work,
        queue,
        SampleWorkCallback);

    if (FAILED(hrWork))
    {
        printf("Error 0x%x submitting work.\r\n", hrWork);
    }
}
```

## 另请参阅

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


## Related topics

- [如何：使用延迟回调](/zh-CN/build/core-features/common/async/async-task-queue-design-howto/using-delayed-callbacks.md)
- [XTaskQueue](/zh-CN/reference/system/xtaskqueue/xtaskqueue_members.md)
- [XTaskQueueRegisterMonitor](/zh-CN/reference/system/xtaskqueue/functions/xtaskqueueregistermonitor.md)
- [XTaskQueueSubmitCallback](/zh-CN/reference/system/xtaskqueue/functions/xtaskqueuesubmitcallback.md)
- [XTaskQueuePort](/zh-CN/reference/system/xtaskqueue/enums/xtaskqueueport.md)