Emitted when a scroll action is performed on a range.
It allows an application to determine the type of scroll event
that occurred and the resultant new value. The application can
handle the event itself and return
TRUE to prevent further
processing. Or, by returning
FALSE, it can pass the event to
other handlers until the default GTK handler is reached.
The value parameter is unrounded. An application that overrides
the ::change-value signal is responsible for clamping the value
to the desired number of decimal digits; the default GTK
handler clamps the value based on
The default handler is called after the handlers added via
The type of scroll action that was performed.
The data is owned by the caller of the function.
The new value resulting from the scroll action.