Every menu has an associated pattern match buffer. As input events that are printable ASCII characters come in, they are appended to this match buffer and tested for a match, as described in menu_driver(3X).
The function set_menu_pattern sets the pattern buffer for the given menu and tries to find the first matching item. If it succeeds, that item becomes current; if not, the current item does not change.
The function menu_pattern returns the pattern buffer of the given menu.
The function menu_pattern returns NULL on error. The function set_menu_pattern may return the following error codes: