pub unsafe extern "C" fn u_copy_file_range_ocall(
    result: *mut ssize_t,
    errno: *mut c_int,
    fd_in: c_int,
    off_in: *mut off64_t,
    fd_out: c_int,
    off_out: *mut off64_t,
    len: size_t,
    flags: c_uint
) -> SgxStatus