Function wcpncpy 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn wcpncpy(
    d: *mut wchar_t,
    s: *const wchar_t,
    n: size_t,
) -> *mut wchar_t

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