小编Den*_*mov的帖子

我有两个相同代码的变体:

{$APPTYPE CONSOLE}

uses
  System.SysUtils;

type
  IMyObject1 = interface
    ['{4411181F-3531-4D30-AB18-A8326F8C2CD0}']
  end;

  IMyObject2 = interface
    ['{41C88E1A-0360-4AC3-B021-125880B23DE5}']
  end;

  TMyObject = class(TInterfacedObject, IMyObject1, IMyObject2)
  public
    destructor Destroy; override;
  end;


destructor TMyObject.Destroy;
begin
  Writeln('Destroy');
  inherited;
end;

procedure Variant1;

  function GetMyObject: IMyObject2;
  var
    Obj1: IMyObject1;
  begin
    Obj1 := TMyObject.Create;
    try
      Obj1.QueryInterface(IMyObject2, Result);
    finally
      Obj1 := nil;
    end;
  end;

var
  Obj2: IMyObject2;
begin
  Obj2 := GetMyObject;
  try
  finally
    Obj2 := nil;
  end;
  Writeln('Variant1 end of proc');
end;

function GetMyObject: IMyObject2;
var
  Obj1: IMyObject1;
begin
  Obj1 := …

我一直认为OleVariant变量的初始值总是等于Unassigned(类型VT_EMPTY).但是下面用XE3编译的简单代码告诉我这不是真的.

{$APPTYPE CONSOLE}

uses
  ActiveX;

function GetValue: OleVariant;
begin
  Result := TVariantArg(Result).vt;
end;

function GetValue2: OleVariant;
begin
  Result := 10;
  Result := GetValue;
end;

var
  Msg: string;
begin
  Msg := GetValue2;
  Writeln(Msg);
end.

App写"3".这是正常的吗？