Continuous variable updation in a text box

[Adeel Malik <adeelmalik78 yahoo com>]

I intend to monitor the variable's value (acquired via data acquisition hardware) at a rate of around 1,000 times per second.
I haven't used textboxes before in GTK+. Could anyone suggest how to update the value of a variable in a textbox etc., at this rate.
 
Thanks,
Adeel