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

Question

unit Unit1;interfaceuses
  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？

Answer 1

Handle没有值直接用吗？