public function traceAt($levels, $replace = false)
    {
        $prev = $this->tracedErrors;
        $this->tracedErrors = (int) $levels;
        if (!$replace) {
            $this->tracedErrors |= $prev;
        }

        return $prev;
    }
public function traceAt($levels, $replace = false)
    {
        $prev = $this->tracedErrors;
        $this->tracedErrors = (int) $levels;
        if (!$replace) {
            $this->tracedErrors |= $prev;
        }

        return $prev;
    }
public function traceAt ( $ levels , $ replace = false ) { $ prev = $ this -> tracedErrors ; $ this -> tracedErrors = ( int ) $ levels ; if ( ! $ replace ) { $ this -> tracedErrors |= $ prev ; } return $ prev ; }
Sets the PHP error levels for which the stack trace is preserved.

@param int  $levels  A bit field of E_* constants for traced errors
@param bool $replace Replace or amend the previous value

@return int The previous value
Sets the PHP error levels for which the stack trace is preserved .