From Linux Man Pages
win - make and break menu window and subwindow associations
SYNOPSIS
#include <menu.h>
int set_menu_win(MENU *menu, WINDOW *win);
WINDOW *menu_win(const MENU *menu);
int set_menu_sub(MENU *menu, WINDOW *sub);
WINDOW *menu_sub(const MENU *menu);
int scale_menu(const MENU *menu, int *rows, int *columns);
DESCRIPTION
Every menu has an associated pair of curses windows. The menu window displays any title and border associated
with the window; the menu subwindow displays the items of the menu that are currently available for selection.
The first four functions get and set those windows. It is not necessary to set either window; by default, the
driver code uses stdscr for both.
In the set_ functions, window argument of NULL is treated as though it were stsdcr. A menu argument of NULL is
treated as a request to change the system default menu window or subwindow.
The function scale_menu returns the minimum size required for the subwindow of menu.
RETURN VALUE
Routines that return pointers return NULL on error. Routines that return an integer return one of the following
error codes:
E_OK The routine succeeded.
E_SYSTEM_ERROR
System error occurred (see errno).
E_BAD_ARGUMENT
Routine detected an incorrect or out-of-range argument.
E_POSTED
The menu has already been posted.
E_NOT_CONNECTED
No items are connected to the menu.
RELATED
ncurses(3), menu(3MENU).
NOTES
The header file <menu.h> automatically includes the header file <curses.h>.
PORTABILITY
These routines emulate the System V menu library. They were not supported on Version 7 or BSD versions.
win(3MENU)
CATEGORY