mitem_visible.3x man page
mitem_visible — check visibility of a menu item
bool item_visible(const ITEM *item);
A menu item is visible when it is in the portion of a posted menu that is mapped onto the screen (if the menu is scrollable, in particular, this portion will be smaller than the whole menu).
The header file <menu.h> automatically includes the header file <curses.h>.
These routines emulate the System V menu library. They were not supported on Version 7 or BSD versions.
Juergen Pfeifer. Manual pages and adaptation for new curses by Eric S. Raymond.