ProgressBar update howto

[Aurélien KAMEL <aurelien kamel gmail com>]

Hello everyone,

I would like to do something but I don't know how. What I want to do  
in one of my function is:

some_code;
open_a_dialog_with_a_progressbar;
while (condition)
	compute_something;
	update_progressbar;
done;
close_dialog;
some_code;

Could someone give me a piece of code to show me how to do this ? All  
my attempts have failed...

Thanks a lot!
Aurélien

ps: sorry for my english... still learning.