What does h_ctrl mean?

[rejii0042]

When I try to operate with handle, I don't understand what the parameter h_ctrl means .

def control_click_by_handle(hwnd, h_ctrl, **kwargs):
    """

    :param handle:
    :param kwargs:
    :return:
    """
    button = kwargs.get("button", "left")
    clicks = kwargs.get("clicks", 1)
    x = kwargs.get("x", INTDEFAULT)
    y = kwargs.get("y", INTDEFAULT)

    ret = AUTO_IT.AU3_ControlClickByHandle(HWND(hwnd), HWND(h_ctrl),
                                           LPCWSTR(button), INT(clicks),
                                           INT(x), INT(y))
    return ret