以UTC格式转换时间

Question

I have following code:

$start_time="6:00 PM";

$end_time="10:00 PM";

The above time are according the countries timezone i.e (Asia/Colombo, Asia/Adelaide...etc)

And I want to perform the following calcuation:

date_default_timezone_set("UTC");
$system_time = date('g:i A'); //Getting the system time according to the UTC timezone

    $time_left_for_discussion = $start_time - $system_time;

    if ($system_day < $day) {
        return "Upcoming";
    } else if ($system_day == $day) {
        if ($time_left_for_discussion <= 0 && $system_time <= $end_time) {
            return "Live";
        } else {
            return "NA";
        }
    } else {
        return "NA";
    }

Here the $system_time is according the UTC timezone. Now I want calculation for $time_left_for_discussion so for that I need need to convert $start_time and $end_time in UTC format for correct calucation.

Hope you got my point.

Answer 1

Try the dateTime class.

$date = new DateTime("2010-07-05T06:00:00Z");
$date->setTimeZone(new DateTimeZone("UTC"));