> ## Documentation Index
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> Use this file to discover all available pages before exploring further.

# XTaskQueueDispatchMode

> XTaskQueueDispatchMode

# XTaskQueueDispatchMode

Describes how task queue callbacks are processed.

## Syntax

```cpp theme={null}
typedef enum class XTaskQueueDispatchMode  : uint32_t  
{  
    Manual,  
    ThreadPool,  
    SerializedThreadPool,  
    Immediate  
} XTaskQueueDispatchMode  
```

## Constants

| Constant             | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| Manual               | Callbacks are not automatically dispatched. Callbacks submitted to a port using this dispatch mode are queued, but must be dispatched manually by [XTaskQueueDispatch](/reference/system/xtaskqueue/functions/xtaskqueuedispatch).<br />**Note:** If you have a thread that pumps Windows messages:<ul><li>Do not dispatch callbacks for the work port</li><li>If you dispatch callbacks for the completion port, you must continue to pump Windows messages for the thread</li></ul><br />For more information, see [Creating a manual task queue](/build/core-features/common/async/async-task-queue-design-howto/creating-manual-task-queue). |
| ThreadPool           | Callbacks submitted to a port using this dispatch mode are queued and automatically dispatched on the system thread queue. The task queue executes the calls in parallel, taking a call to execute from the task queue in turn as thread pool threads become available.<br />For more information about creating a thread pool task queue, see [Creating a thread pool task queue](/build/core-features/common/async/async-task-queue-design-howto/creating-thread-pool-task-queue).                                                                                                                                                             |
| SerializedThreadPool | Callbacks submitted to a port using this dispatch mode are queued and automatically dispatched on the system thread queue. Unlike `ThreadPool`, the task queue executes the calls in serial, one at a time, on the thread pool.                                                                                                                                                                                                                                                                                                                                                                                                                  |
| Immediate            | Callbacks are not queued at all, but are executed immediately on the thread that submitted them. For an example that implements the immediate dispatch mode, see [Creating a composite task queue](/build/core-features/common/async/async-task-queue-design-howto/creating-composite-task-queue).                                                                                                                                                                                                                                                                                                                                               |

## Remarks

This enumeration is used by [XTaskQueueCreate](/reference/system/xtaskqueue/functions/xtaskqueuecreate) to specify the dispatch modes for the work and completion ports of a task queue.

The work port and completion port can use different dispatch modes. For example, you can use the thread pool dispatch mode for the work port to automatically queue & execute callbacks in parallel on the system thread queue, and use the manual dispatch mode for the completion port to manually queue & execute callbacks on the Windows message loop thread. For more information, see [Using a task queue with a Windows message loop](/build/core-features/common/async/async-task-queue-design-howto/task-queue-windows-msg-loop).

## Requirements

**Header:** XTaskQueue.h

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

## 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)