用Delphi 5 调用 VC++ 6 的dll类中的函数出现问题(Access Violation)(100分)

Delphi 代码:
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls;
...
type
TSample=class(TObject)
public
function ok():Boolean;virtual;cdecl;abstract;
end;

type
pTSample=^TSample;
var
Form1: TForm1;
pSampleTSample;
function CreateInstance()TSample;cdecl;far;external 'httpdll';
procedure DeleteInstance(psampleTSample);cdecl;far;external 'httpdll';

implementation
{$R *.DFM}
procedure TForm1.Button1Click(Sender: TObject);
begin
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
pSample:=CreateInstance();
pSample^.ok();
//调用时出现"Access Violation at..."对话框
DeleteInstance(pSample);
end;

end.

VC++代码:
declaration:
#define DllExport __declspec(dllexport)
extern "C" DllExport sample * __cdecl CreateInstance();
extern "C" DllExport void __cdecl DeleteInstance(sample * Instance);
class DllExport sample
{
public:
virtual BOOL __cdecl ok();
};

definitions:
BOOL __cdecl sample:k()
{
MessageBox(NULL,"Hello","In Dll",0);
return 1;
}
extern "C" DllExport sample * __cdecl CreateInstance()
{
return (new sample);
}
extern "C" DllExport void __cdecl DeleteInstance(sample * Instance)
{
delete Instance;
}

tell me too

楼上兄台，看看这里的观点吧，说是行不通
http://www.csdn.net/expert/topic/88/88183.shtm

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用接口吧

Sorry
好久没来，忘了
看来由于编译器的不同，只能用COM规范解决了