帮我看一看错误 
//dll中:
var
  Dllform: TDllform;
  function ShowCalendar(AHandle: THandle; ACaption: pchar): TDateTime;
implementation{$R *.DFM}
function ShowCalendar(AHandle: THandle; ACaption:pchar): TDateTime;
begin
  Application.Handle := AHandle;
  DLLForm := TDLLForm.Create(Application); //创建并显示窗体
  try
  DLLForm.Caption := ACaption;
  DLLForm.ShowModal; //显示方式为模式化
  Result := DLLForm.calDLLCalendar.date; //返回设定日期
  finally
  DLLForm.Free; //用完后卸载该窗体end;
end;
end;
//调用:
type
 Tcalnedar=function ShowCalendar(AHandle: THandle; ACaption: pchar):TDateTime;stdcall;
//出错[Error] Unit1.pas(10): Function needs result typeprocedure TForm1.Button1Click(Sender: TObject);
var
 libhandle:Thandle;
 calendar:Tcalendar;
begin
 libhandle:=loadlibrary('testdll.dll');
 try
 if libhandle=0 then
    exit;
 @calendar:=Getprocaddress(libhandle,ShowCalendar);
  if not (@calendar=nil) then
  edit1.text:=ShowCalendar(application.handle,'testdll');
  finally
  exit;
end;
 end;