unit KillThread;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Label1: TLabel;
    procedure Button1Click(Sender: TObject);
  private
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  ThreadHandle: THandle;   // holds a handle to the thread

implementation

{$R *.DFM}

function ThreadFunction(Info: Pointer): Integer; stdcall
var
  Count: Integer;     // general loop counter
  FormDC: HDC;        // holds a handle to the form device context
  CountStr: string;   // holds a string representation of Count
begin
  {retrieve a handle to the form's device context}
  FormDC := GetDC(Form1.Handle);

  {show something visual}
  for Count := 1 to 10000 do begin
    CountStr := IntToStr(Count);
    TextOut(FormDC, 10, 10, Pchar(CountStr), Length(CountStr));
  end;

  {release the device context}
  ReleaseDC(Form1.Handle, FormDC);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  ThreadId: DWORD;     // holds the thread identifier
  ExitCode: DWORD;     // holds the thread exit code
begin
  {create and execute a thread}
  ThreadHandle := CreateThread(nil, 0, @ThreadFunction, nil, 0, ThreadId);
  if ThreadHandle = 0 then
    ShowMessage('Thread not Started');

  {pause for a very short period}
  Sleep(50);

  {discontinue the thread prematurely}
  TerminateThread(ThreadHandle, 4);

  {retrieve and display the thread's exit code}
  GetExitCodeThread(ThreadHandle, ExitCode);
  Label1.Caption := 'The Thread is Terminated with '+ IntToStr(ExitCode)+
                    ' as the Exit Code';
end;

end.