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

# XblAchievementsAddAchievementProgressChangeHandler

> XblAchievementsAddAchievementProgressChangeHandler

Registers an event handler for achievement progress change notifications.

## Syntax

```cpp theme={null}
XblFunctionContext XblAchievementsAddAchievementProgressChangeHandler(  
         XblContextHandle xblContextHandle,  
         XblAchievementsProgressChangeHandler handler,  
         void* handlerContext  
)  
```

### Parameters

*xblContextHandle*   \_In\_\
Type: [XblContextHandle](https://docs.xbox.com/reference/live/xsapi-c/types_c/handles/xblcontexthandle.md)

An XBOX services context handle created with XblContextCreateHandle.

*handler*   \_In\_\
Type: XblAchievementsProgressChangeHandler

The callback function that receives notifications.

*handlerContext*   \_In\_opt\_\
Type: void\*

Client context pointer to be passed back to the handler.

### Return value

Type: XblFunctionContext

A XblFunctionContext used to remove the handler.

## Remarks

Call [XblAchievementsRemoveAchievementProgressChangeHandler](https://docs.xbox.com/reference/live/xsapi-c/achievements_c/functions/xblachievementsremoveachievementprogresschangehandler.md) to un-register event handler.

## Requirements

**Header:** achievements\_c.h

**Library:** Microsoft.Xbox.Services.142.C.lib or Microsoft.Xbox.Services.143.C.lib

## See also

[achievements\_c](https://docs.xbox.com/reference/live/xsapi-c/achievements_c/achievements_c_members.md)


## Related topics

- [XblAchievementsRemoveAchievementProgressChangeHandler](https://docs.xbox.com/reference/live/xsapi-c/achievements_c/functions/xblachievementsremoveachievementprogresschangehandler.md)
- [achievements_c (contents)](https://docs.xbox.com/reference/live/xsapi-c/achievements_c/achievements_c_members.md)
- [XblAchievementsProgressChangeHandler](https://docs.xbox.com/reference/live/xsapi-c/achievements_c/functions/xblachievementsprogresschangehandler.md)
- [XblAchievementProgressChangeEntry](https://docs.xbox.com/reference/live/xsapi-c/achievements_c/structs/xblachievementprogresschangeentry.md)
- [XblAchievementUnlockAddNotificationHandler](https://docs.xbox.com/reference/live/xsapi-c/achievements_c/functions/xblachievementunlockaddnotificationhandler.md)