Event 21,4 (changes)
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Programmer's Reference Manuals
» Events
» Event Numbers
» Expansion Event
» Event 21,4
Mouse alternate positioning device update
| Entry | |
|---|---|
| R0 | 21 (&15) |
| R1 | 4 |
| R2 | Signed X change in position of alternate device (positive = right) |
| R3 | Signed Y change in position of alternate device (positive = “up”/away from user) |
Use
The OS issues this event when the pointer driver indicates a change in the position of the “alternate positioning device” (i.e. scroll wheel).
Software which receives this event via EventV can claim the vector call in order to prevent the accumulator values returned OS_Pointer 2 from being updated.
Drivers should use PointerV 4 or PointerV 9 to communicate changes in the alternate positioning device to the OS.
See also
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