Setting format to 0 indicates a 3-2-3 arrangement of the labels, 1 indicates a 4-4 arrangement and 2 indicates the PC like 4-4-4 mode, but in addition an index line will be created.
Funtion ncurses_slk_init() must be called before ncurses_initscr() or ncurses_newterm() is called. If ncurses_initscr() eventually uses a line from stdscr to emulate the soft labels, then format determines how the labels are arranged of the screen. Setting format to 0 indicates a 3-2-3 arrangement of the labels, 1 indicates a 4-4 arrangement and 2 indicates the PC like 4-4-4 mode, but in addition an index line will be created.