isbadcodeptru.pas

DelphiWin32核心API参考光盘内容.是学习书籍中的源码,便于学习.

unit IsBadCodePtru;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
var
  TestPtr: Pointer;   // an untyped pointer of questionable access
begin
  {try for a valid read address}
  Testptr := @TForm1.Button1Click;
  if IsBadCodePtr(Testptr)
    then ShowMessage('no read access')
    else ShowMessage('valid read access');
end;


procedure TForm1.Button2Click(Sender: TObject);
var
  TestPtr: Pointer;   // an untyped pointer of questionable access
begin
  {try for an invalid read address}
  TestPtr := Pointer($7FFFFFFF);
  if IsBadCodePtr(Testptr)
    then ShowMessage('no read access')
    else ShowMessage('valid read access');
end;

end.