Status for long-running operation

[Jeffrey Barish <jeff_barish earthlink net>]

My application has one operation that runs for a long time (~1 minute).  
During this time, the user is not allowed to do anything.  Nevertheless, I 
felt that it was important to give the user some feedback that the 
application is still alive and that the operation is running.  My solution 
was to print a message in a TextBuffer and follow the message with a string 
of dots that grows in length by one every second.  To get the TextView to 
update, I used events_pending/main_iteration.  This all works nicely.  
However, because of the events_pending/main_iteration statements, the entire 
GUI is now alive.  Thus, the user is able to do things that disrupt the 
long-running operation.  Basically, what I want is a way to get the TextView 
to update so that I can update the progress indicator but for everything 
else still to be locked out.  Is there a way to do this?
-- 
Jeffrey Barish