Does signal trap of CTRL-CLOSE event allowable to be used on windows?

[Tatsuro MATSUOKA]

Hello

Pressing 'X' button on the right upper side windows console always induce error.
If we use  SetConsoleCtrlHandler function and trap CTRL-CLOSE event, we may 
eliminate annoy the error.

In src/sighandlers.cc,  I found

#**From here
#ifdef USE_W32_SIGINT
static BOOL CALLBACK
w32_sigint_handler (DWORD sig)
{
  const char *sig_name;

  switch(sig)
    {
      case CTRL_BREAK_EVENT:
        sig_name = "Ctrl-Break";
        break;
      case CTRL_C_EVENT:
        sig_name = "Ctrl-C";
        break;
      case CTRL_CLOSE_EVENT:
        sig_name = "close console";
        break;
      case CTRL_LOGOFF_EVENT:
        sig_name = "logoff";
        break;
      case CTRL_SHUTDOWN_EVENT:
        sig_name = "shutdown";
        break;
      default:
        sig_name = "unknown console event";
        break;
    }

  switch(sig)
    {
      case CTRL_BREAK_EVENT:
      case CTRL_C_EVENT:
        w32_raise (SIGINT);
        break;

      case CTRL_CLOSE_EVENT:
      case CTRL_LOGOFF_EVENT:
      case CTRL_SHUTDOWN_EVENT:
      default:
        // We should do the following:
        //    clean_up_and_exit (0);
        // We can't because we aren't running in the normal Octave thread.
        user_abort(sig_name, sig);
        break;
    }

  // Return TRUE if the event was handled, or FALSE if another handler
  // should be called.
  // FIXME check that windows terminates the thread.
  return TRUE;
}
# ***********here END

If we manipulate arround       
  case CTRL_CLOSE_EVENT:

we may avoid the annoying the error.

Regards

Tatsuro