- ini_set: documentation ( source)
<?php
ini_set("date.timezone", "GMT");
$objDateTo = new dateTime('2017-10-01');
$objDateFrom = new dateTime('2017-01-01');
$interval = $objDateTo->diff($objDateFrom);
echo "Date Only: " . $interval->m . "\r\n";
$objDateTo = new dateTime('2017-10-01 12:00:00');
$objDateFrom = new dateTime('2017-01-01 12:00:00');
$interval = $objDateTo->diff($objDateFrom);
echo "Date and Time: " . $interval->m;