confused about arrow key syms

[Skip Montanaro <skip pobox com>]

What keys do the following similar keysyms correspond to (all names from
gdkkeysyms.h):

    GDK_Up
    GDK_Page_Up
    GDK_KP_Up
    GDK_KP_Page_Up

The up arrow key on my laptop (it only has an inverted T set of arrow keys)
generates GDK_Up.  I presume if it had a separate numeric keypad with
embedded arrow keys, the up arrow key there would generate GDK_KP_Up.  Where
do the Page_Up variations come into play?  What keys might generate them?

Thx,

Skip (whose trying to figure out what events he needs to listen to...)