Function lv_text_get_next_line 

pub unsafe extern "C" fn lv_text_get_next_line(
    txt: *const i8,
    len: u32,
    font: *const _lv_font_t,
    letter_space: i32,
    max_width: i32,
    used_width: *mut i32,
    flag: u32,
) -> u32