GtkSpinButton::set_wrap
void set_wrap(bool wrap);
Where set_wrap() is set to
true, the spinbutton having displayed the upper
bound of its value range will return to the lower bound on the next
step increment. In other words, if the range is 1 to 10, 1 will follow
10 in the display area when the up arrow is pressed.
The default setting is false, which greys out the
appropriate arrow when the lower or upper bound of the range is reached.