DLL中传递引用的问题(100分)

DLL中如何传递引用？请举一例子！如在DLL中用引用传递返回一Pchar!

参数前加上 var

dll:
library test;
uses
ShareMem,
SysUtils,
Classes;
function test(testchar):integer;export;stdcall;
begin
Strcopy(test,Pchar('123'));
test:=0;
end;
exports
test;
begin
end.

unit unit1;

interface

uses
Sharemem,Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls;

type
TForm1 = class(TForm)
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;
function test(testChar):integer;stdcall;external 'Project2.dll';
implementation

{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
var s:String;
begin
setlength(s,100);
test(pchar(s));
end;
end.

不能加VAR!!

接受答案了.