Function mbsnrtowcs 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn mbsnrtowcs(
    dst_ptr: *mut wchar_t,
    src_ptr: *mut *const c_char,
    src_len: size_t,
    dst_len: size_t,
    ps: *mut mbstate_t,
) -> size_t

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

Convert a multibyte string to a wide string with a limited amount of bytes.