delphi调用SCardEstablishContext，编译没报错，执行的时候报错

[weixin_40010593]

unit Unit1;

interface

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

type
TForm1 = class(TForm)
Button1: TButton;
Edit1: TEdit;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;
function SCardEstablishContext(dwScope:LongInt;pvReserved1:Pointer;pvReserved2:Pointer;phContext:Thandle):LongInt;stdcall;external'WinSCard.dll';

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);

var
ret:LongInt;
hSC:Thandle;

begin
ret := SCardEstablishContext(0,nil,nil,hSC);
if ret <> 0 then
Edit1.Text:='false'
else
Edit1.Text:='true';
end;

end.
报错信息
‘Access violation at address 0042F838 in module 'Project1.exe',read of address CD00FFEC ’

再有顺便问一下想拿delphi做一个读M1卡的程序，使用Smart card相关函数能实现吗？

[weixin_40010593]

挺急的，我是小白，还望大神指导

[pkdebug]

Handle没有值直接用吗？