PHPOffice / PhpSpreadsheet

     * @param integer $col    Zero indexed column

     * @param mixed   $xfIndex The XF format index

     */

    public function writeBlank($row, $col, $xfIndex)

    {

        $record    = 0x0201;                 // Record identifier

        $length    = 0x0006;                 // Number of bytes to follow

        $header    = pack("vv", $record, $length);

        $data      = pack("vvv", $row, $col, $xfIndex);

        $this->append($header . $data);

        return 0;

    }

    /**

     * Write a boolean or an error type to the specified row and column (zero indexed)

     * @param boolean $isError Error or Boolean?

     * @param int $xfIndex

     */

    private function writeBoolErr($row, $col, $value, $isError, $xfIndex)

    {

        $record = 0x0205;

        $length = 8;

        $header    = pack("vv", $record, $length);

        $data      = pack("vvvCC", $row, $col, $xfIndex, $value, $isError);

        $this->append($header . $data);

        return 0;

    }

    /**

     * Write a formula to the specified row and column (zero indexed).