System单元对所有与COM相关的声明就这么多，需要倒背如流

是首先是VM表，但是和COM相关的函数地址都废弃了，这几个VM函数具体放在哪里，还得在研究：

{ Virtual method table entries }

  vmtSelfPtr           = -76;
  vmtIntfTable         = -72;
  vmtAutoTable         = -68;
  vmtInitTable         = -64;
  vmtTypeInfo          = -60;
  vmtFieldTable        = -56;
  vmtMethodTable       = -52;
  vmtDynamicTable      = -48;
  vmtClassName         = -44;
  vmtInstanceSize      = -40;
  vmtParent            = -36;
  vmtSafeCallException = -32 deprecated;  // don't use these constants.
  vmtAfterConstruction = -28 deprecated;  // use VMTOFFSET in asm code instead
  vmtBeforeDestruction = -24 deprecated;
  vmtDispatch          = -20 deprecated;
  vmtDefaultHandler    = -16 deprecated;
  vmtNewInstance       = -12 deprecated;
  vmtFreeInstance      = -8 deprecated;
  vmtDestroy           = -4 deprecated;

  vmtQueryInterface    = 0 deprecated;
  vmtAddRef            = 4 deprecated;
  vmtRelease           = 8 deprecated;
  vmtCreateObject      = 12 deprecated;

其次是所有与COM相关的声明与定义：

type

  TObject = class;

  TClass = class of TObject;

  HRESULT = type Longint;  { from WTYPES.H }
  {$EXTERNALSYM HRESULT}

  PGUID = ^TGUID;
  TGUID = packed record
    D1: LongWord;
    D2: Word;
    D3: Word;
    D4: array[0..7] of Byte;
  end;

  PInterfaceEntry = ^TInterfaceEntry;
  TInterfaceEntry = packed record
    IID: TGUID;
    VTable: Pointer;
    IOffset: Integer;
    ImplGetter: Integer;
  end;

  PInterfaceTable = ^TInterfaceTable;
  TInterfaceTable = packed record
    EntryCount: Integer;
    Entries: array[0..9999] of TInterfaceEntry;
  end;

  TMethod = record
    Code, Data: Pointer;
  end;

const
  S_OK = 0;                             {$EXTERNALSYM S_OK}
  S_FALSE = $00000001;                  {$EXTERNALSYM S_FALSE}
  E_NOINTERFACE = HRESULT($80004002);   {$EXTERNALSYM E_NOINTERFACE}
  E_UNEXPECTED = HRESULT($8000FFFF);    {$EXTERNALSYM E_UNEXPECTED}
  E_NOTIMPL = HRESULT($80004001);       {$EXTERNALSYM E_NOTIMPL}

type
  IInterface = interface
    ['{00000000-0000-0000-C000-000000000046}']
    function QueryInterface(const IID: TGUID; out Obj): HResult; stdcall;
    function _AddRef: Integer; stdcall;
    function _Release: Integer; stdcall;
  end;

  IUnknown = IInterface;
{$M+}
  IInvokable = interface(IInterface)
  end;
{$M-}

  IDispatch = interface(IUnknown)
    ['{00020400-0000-0000-C000-000000000046}']
    function GetTypeInfoCount(out Count: Integer): HResult; stdcall;
    function GetTypeInfo(Index, LocaleID: Integer; out TypeInfo): HResult; stdcall;
    function GetIDsOfNames(const IID: TGUID; Names: Pointer;
      NameCount, LocaleID: Integer; DispIDs: Pointer): HResult; stdcall;
    function Invoke(DispID: Integer; const IID: TGUID; LocaleID: Integer;
      Flags: Word; var Params; VarResult, ExcepInfo, ArgErr: Pointer): HResult; stdcall;
  end;

{$EXTERNALSYM IUnknown}
{$EXTERNALSYM IDispatch}

{ TInterfacedObject provides a threadsafe default implementation
  of IInterface.  You should use TInterfaceObject as the base class
  of objects implementing interfaces.  }

  TInterfacedObject = class(TObject, IInterface)
  protected
    FRefCount: Integer;
    function QueryInterface(const IID: TGUID; out Obj): HResult; stdcall;
    function _AddRef: Integer; stdcall;
    function _Release: Integer; stdcall;
  public
    procedure AfterConstruction; override;
    procedure BeforeDestruction; override;
    class function NewInstance: TObject; override;
    property RefCount: Integer read FRefCount;
  end;

  TInterfacedClass = class of TInterfacedObject;

{ TAggregatedObject and TContainedObject are suitable base
  classes for interfaced objects intended to be aggregated
  or contained in an outer controlling object.  When using
  the "implements" syntax on an interface property in
  an outer object class declaration, use these types
  to implement the inner object.

  Interfaces implemented by aggregated objects on behalf of
  the controller should not be distinguishable from other
  interfaces provided by the controller.  Aggregated objects
  must not maintain their own reference count - they must
  have the same lifetime as their controller.  To achieve this,
  aggregated objects reflect the reference count methods
  to the controller.

  TAggregatedObject simply reflects QueryInterface calls to
  its controller.  From such an aggregated object, one can
  obtain any interface that the controller supports, and
  only interfaces that the controller supports.  This is
  useful for implementing a controller class that uses one
  or more internal objects to implement the interfaces declared
  on the controller class.  Aggregation promotes implementation
  sharing across the object hierarchy.

  TAggregatedObject is what most aggregate objects should
  inherit from, especially when used in conjunction with
  the "implements" syntax.  }

  TAggregatedObject = class(TObject)
  private
    FController: Pointer;  // weak reference to controller
    function GetController: IInterface;
  protected
    { IInterface }
    function QueryInterface(const IID: TGUID; out Obj): HResult; stdcall;
    function _AddRef: Integer; stdcall;
    function _Release: Integer; stdcall;
  public
    constructor Create(const Controller: IInterface);
    property Controller: IInterface read GetController;
  end;

  { TContainedObject is an aggregated object that isolates
    QueryInterface on the aggregate from the controller.
    TContainedObject will return only interfaces that the
    contained object itself implements, not interfaces
    that the controller implements.  This is useful for
    implementing nodes that are attached to a controller and
    have the same lifetime as the controller, but whose
    interface identity is separate from the controller.
    You might do this if you don't want the consumers of
    an aggregated interface to have access to other interfaces
    implemented by the controller - forced encapsulation.
    This is a less common case than TAggregatedObject.  }

  TContainedObject = class(TAggregatedObject, IInterface)
  protected
    { IInterface }
    function QueryInterface(const IID: TGUID; out Obj): HResult; virtual; stdcall;
  end;

里面的英文说明还得翻译如下：