---
title: dispatchRelativeScrollWheelEvent
framework: hiddriverkit
role: symbol
role_heading: Instance Method
path: hiddriverkit/iohideventservice/dispatchrelativescrollwheelevent
---

# dispatchRelativeScrollWheelEvent

Dispatches a relative scroll wheel event to the system.

## Declaration

```occ
virtual kern_return_t dispatchRelativeScrollWheelEvent(uint64_t timeStamp, IOFixed dx, IOFixed dy, IOFixed dz, IOOptionBits options, bool accelerate);
```

## Parameters

- `timeStamp`: The timestamp of the event. Use the timestamp of the report element that is the source of the event.
- `dx`: The delta X value.
- `dy`: The delta Y value.
- `dz`: The delta Z value.
- `options`: Additional options for scrolling-related events. Specify 0 for no options. For a list of other values, see doc://com.apple.hiddriverkit/documentation/HIDDriverKit/IOHIDScrollEventOptions.
- `accelerate`: Scroll events are subject to an acceleration algorithm. Pass in false if you don’t wish to have acceleration logic applied to the scroll event.

## Return Value

Return Value kIOReturnSuccess on success, or another value if an error occurs. See Error Codes.

## Discussion

Discussion Call this method from your event service to dispatch a scroll-wheel event to the system. Typically, you call this method when handling a report from the device, after you determine that the report originated from scroll-wheel hardware or otherwise represents a scrolling event.

## See Also

### Dispatching Events

- [dispatchKeyboardEvent](hiddriverkit/iohideventservice/dispatchkeyboardevent.md)
- [dispatchRelativePointerEvent](hiddriverkit/iohideventservice/dispatchrelativepointerevent.md)
- [dispatchAbsolutePointerEvent](hiddriverkit/iohideventservice/dispatchabsolutepointerevent.md)
- [dispatchDigitizerStylusEvent](hiddriverkit/iohideventservice/dispatchdigitizerstylusevent.md)
- [dispatchDigitizerTouchEvent](hiddriverkit/iohideventservice/dispatchdigitizertouchevent.md)
- [dispatchEvent](hiddriverkit/iohideventservice/dispatchevent.md)
- [IOHIDKeyboardEventOptions](hiddriverkit/iohidkeyboardeventoptions.md)
- [IOHIDPointerEventOptions](hiddriverkit/iohidpointereventoptions.md)
- [IOHIDScrollEventOptions](hiddriverkit/iohidscrolleventoptions.md)