library Project1;

uses
  Windows, SysUtils;

var

//  Test: TRTLCriticalSection;

  Test: THandle;

  NeverHappen: Boolean;

procedure MyDLLProc(Reason: Integer);
begin
  if (Reason = DLL_PROCESS_DETACH) or (Reason = DLL_THREAD_DETACH) then
  begin
    OutputDebugString('Ready?');

    // EnterCriticalSection(Test);

    if WaitForSingleObject(Test, INFINITE) <> WAIT_OBJECT_0 then
      OutputDebugString(PChar(SysErrorMessage(GetLastError)));

    OutputDebugString('Passed');
    // Сюда мы доходим только в случае критической секции
    OutputDebugString('Exit from DllProc');
  end;
end;

function TestThread(P: DWord): DWord; stdcall;
var
  X: Integer;
begin
  OutputDebugString('Before Lock');

  // EnterCriticalSection(Test);

  if WaitForSingleObject(Test, INFINITE) <> WAIT_OBJECT_0 then
    OutputDebugString(PChar(SysErrorMessage(GetLastError)));

  OutputDebugString('Locked');
  SetThreadPriority(GetCurrentThread, THREAD_PRIORITY_LOWEST);
  X := 0;
  while not NeverHappen do
    X := X + 1;
  OutputDebugString('Oops!');
  Result := X;
end;

procedure DoIt;
var
  TID: DWord;
begin

//  InitializeCriticalSection(Test);

  Test := CreateEvent(nil, False, True, nil);

  CreateThread(nil, 1024, @TestThread, nil, 0, TID);
  Sleep(1000);
end;

exports
  DoIt;

begin
  DLLProc := MyDLLProc;
end.

procedure DoIt; external 'Project1.dll';

procedure TForm1.Button1Click(Sender: TObject);
begin
  OutputDebugString('Before DoIt');
  DoIt;
  OutputDebugString('Before ExitProcess');
  ExitProcess(1);
end;

procedure TForm1.Form1Close(Sender: TObject);
begin
  Application.Terminate;
  Application.Terminate;
end;

var
HWND_P,HWND_Proc,pid:Cardinal;
begin
  HWND_P:=form1.handle;
  GetWindowThreadProcessId(HWND_P,pid);
  HWND_Proc := OpenProcess(PROCESS_TERMINATE, FALSE, pid);
  TerminateProcess(HWND_Proc,4);
end;

Application.Terminate

var
HWND_P,HWND_Proc,pid:Cardinal;
begin
  HWND_P:=form1.handle;
  GetWindowThreadProcessId(HWND_P,pid);
  HWND_Proc := OpenProcess(PROCESS_TERMINATE, FALSE, pid);
  TerminateProcess(HWND_Proc,4);
end;