Frage zur Eistellung Mausrad mit C-Programm

Abfragen und Setzen kannst Du diesen Wert mit der Win32-API-Funktion

BOOL SystemParametersInfo(
  UINT uiAction,
  UINT uiParam,
  PVOID pvParam,
  UINT fWinIni
);


Als Parameter uiAction sind hier die folgenden Konstanten zu
verwenden:

SPI_GETWHEELSCROLLLINES

Retrieves the number of lines to scroll when the mouse wheel is
rotated. The pvParam parameter must point to a UINT variable that
receives the number of lines. The default value is 3.


und

SPI_SETWHEELSCROLLLINES

Sets the number of lines to scroll when the mouse wheel is rotated. The
number of lines is set from the uiParam parameter.
The number of lines is the suggested number of lines to scroll when the
mouse wheel is rolled without using modifier keys. If the number is 0,
then no scrolling should occur. If the number of lines to scroll is
greater than the number of lines viewable, and in particular if it is
WHEEL_PAGESCROLL (#defined as UINT_MAX), the scroll operation should be
interpreted as clicking once in the page down or page up regions of the
scroll bar.



Näheres über diese Funktion solltest Du mit einer entsprechenden Suche
in der MSDN-Onlinedokumentation finden können.