Export::writeTempFile

protected function writeTempFile($data, $precedeUtf8Bom = true)
{
	$file = fopen($this->filePath, 'ab');
	if(is_resource($file))
	{
		// add UTF-8 BOM marker
		if (BitrixMainApplication::isUtfMode() || defined('BX_UTF'))
		{
			if($precedeUtf8Bom === true && (filesize($this->filePath) === 0))
			{
				fwrite($file, chr(239).chr(187).chr(191));
			}
		}
		fwrite($file, $data);
		fclose($file);
		unset($file);

		$this->fileSize = filesize($this->filePath);
	}
}