changing keyboard on the fly

["Boncek, John" <jboncek Hunter COM>]

I've searched high and low and can't find any information about how to
change keyboard layout within a GTK application.  I don't need to remap
keys or anything similar.  I want everything to be standard wrt the
keyboard in question, but I need to allow a user to select which of a
number of standard keyboard layouts they are using, including US, Greek,
Russian, etc.  I've found some information about GdkKeymap and how it's
used to interpret keyboard state but nothing about selecting a different
keyboard.  The application needs to do this because it's an embedded
turnkey app running under IceWM; the IceWM environment will not be exposed
to the user.