swick@ATHENA.MIT.EDU (Ralph R. Swick) (10/24/88)
> Floating point variables can not be used directly in callbacks
Correct. Unfortunately this is a major interface change for
applications, though admittedly, they are currently non-portable.
In R3, Scrollbar will provide an additional callback list,
XtNjumpProc, which has the same semantics as XtNthumbProc but
passes the percent by reference. This way we won't break all
applications on day 1.