_pfit(func, ser, order, pstat, _dwin)
{
        local evalstr;

        if (pstat == 1)
        {
                if (_checkdwin)
                {
                        evalstr = sprintf("Pfit(%s, %s)", ser, order);
                }
        }
        else
        {
                if (_checkdwin)
                {
                        evalstr = sprintf("Pfit(%s, %s, 0)", ser, order);
                }
        }

        evalstr = sprintf("setwf(%s, '%s')", _dwin, evalstr);

        eval(evalstr);
}