post-menu displays a menu to its associated
subwindow. To trigger physical display of the subwindow, use refresh
or some equivalent curses routine (the implicit doupdate triggered by
an curses input request will do).
post-menu resets the
selection status of all items.
unpost-menu erases menu from its associated
These routines return one of the following:
E_POSTED if the
menu has already been posted,
E_BAD_STATE if the routine was
called from an initialization or termination function,
E_NO_ROOM if the menu is too large for its window, or
E_NOT_POSTED if the menu has not been posted.