understanding GTK thread capabilities

[kobyleski thierry <thierry kobyleski worldonline fr>]

Can't someone confirm it is possible to do the following (just if it is
possible):
I press a button which starts a long work, and I need to see the cpu
load in another widget in the same form. Is it possible to update the
value of the cpu load in a label wigdet for example, while the callback
from the button is still at work (and is not yet returned to the main
loop).
Thank's a lot.