Getting the selection from GtkText

[Anders Melchiorsen <and kampsax dtu dk>]

Isn't there a simple way to get the selection from a GtkText widget? I
am thinking of something with an interface as simple as
gtk_editable_select_region() but I cannot seem to find anything?

I have a function that is acting upon the contents of a GtkText
widget, but if the user has marked a region I only want the function
to act upon that part of the widget. What is the easiest way to
achieve this?
-- 
Mvh. Anders