php如何判断当前的操作系统是linux还是windows

php$start = new DateTime('2023-10-01');$end = new DateTime('2023-12-31');$interval = DateInterval::createFromDateString('first thursday');$period = new DatePeriod($start, $interval, $end, DatePeriod::EXCLUDE_START_DATE);foreach ($period as $date) { echo $date->format...