Function wcsnrtombs 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn wcsnrtombs(
    dest: *mut c_char,
    src: *mut *const wchar_t,
    nwc: size_t,
    len: size_t,
    ps: *mut mbstate_t,
) -> size_t

See https://pubs.opengroup.org/onlinepubs/9799919799/functions/wcsnrtombs.html.