PRB: ExitWindowsEx with EWX_LOGOFF Doesn't Work Properly

• Microsoft Win32 Software Development Kit (SDK) version 4.0

SYMPTOMS

When an application calls ExitWindowsEx with EWX_LOGOFF in Windows 95, the application itself does not exit. Additionally, the use of the EWX_FORCE flag in conjunction with EWX_LOGOFF will cause undefined behavior.

CAUSE

It is the application's responsibility to terminate itself. However, limitations of the implementation of ExitWindowsEx in Windows 95 require that the application execute the ExitWindowsEx call and terminate itself in a particular way.

RESOLUTION

Code similar to the following will correctly perform a logoff in Windows 95:

   case IDM_LOGOFF:
      {
      DWORD    dw;
      HANDLE   hThread;

      g_hwndParent = hWnd;

      hThread = CreateThread( NULL,
                              0,
                              (LPTHREAD_START_ROUTINE)ShutdownThread,
                              (LPVOID)0,
                              0,
                              &dw);

      if(hThread)
         CloseHandle(hThread);
      }
      break;

/**************************************************************************

   ShutdownThread()

BOOL WINAPI ShutdownThread(DWORD dwCmd) { BOOL f;

f = ExitWindowsEx(EWX_LOGOFF, 0);

//if the shutdown worked, terminate the calling app

   {
   if(g_hwndParent)
       {
       //shutdown the calling app ASAP, don't destroy the window
       PostMessage(g_hwndParent, WM_QUIT, 0, 0);
       }
   }

STATUS

This behavior is by design.