GtkSpinButton::configure
void configure(
      GtkAdjustment 
      adjustment
     , double climb_rate, int digits); 
    
     This method sets the GtkAdjustment and
     configures the rate of the spin and number of decimal points displayed
     in an existing spinbutton.
    
    
     Configuration settings made in this way will overwrite any existing
     settings on the calling GtkSpinButton.