DECLARE_INTERFACE_(ISubunit, IUnknown)
{
    // 获取子单元的类型
    STDMETHOD(GetSubunitType)(THIS_
        _Out_  GUID *pSubunitType
    ) PURE;

    // 获取子单元的控制接口
    STDMETHOD(QueryInterface)(THIS_
        _In_   REFIID iid,
        _Out_  PVOID *ppvObject
    ) PURE;

    // 获取子单元的状态
    STDMETHOD(GetPart)(THIS_
        _Out_  IPart **ppIPart
    ) PURE;

    // 获取子单元的唯一标识符
    STDMETHOD(GetSubunitId)(THIS_
        _Out_  UINT *pnId
    ) PURE;

    // 获取子单元的连接数
    STDMETHOD(GetConnectionCount)(THIS_
        _Out_  UINT *pCount
    ) PURE;

    // 获取子单元的连接
    STDMETHOD(GetConnection)(THIS_
        _In_   UINT nIndex,
        _Out_  IConnection **ppConnection
    ) PURE;

    // 获取子单元的默认连接
    STDMETHOD(GetDefaultConnection)(THIS_
        _Out_  IConnection **ppConnection
    ) PURE;
};