Does DateTime::__construct() support milliseconds in PHP 7.1

Question

Information shows that in version 7.1, DateTime::__construct() can already support milliseconds. And specifically emphasize:

This means that naive comparisons of two newly created instances will now more likely return FALSE instead of TRUE: new DateTime() == new DateTime()

However, in my code, the millisecond part is always "000000", what is the problem:

<?php
for ($i = 0; $i < 10000; ++$i) {
    $date = new DateTime();
//    if ($date->format('u') != '000000') {
        file_put_contents('./msec.log', "$i:\t" . $date->format('s.u') . PHP_EOL, FILE_APPEND);
//    }
}

Output:

0:      51.000000
1:      51.000000
2:      51.000000
……
4999:   51.000000
5000:   51.000000
5001:   51.000000
……
9997:   51.000000
9998:   51.000000
9999:   51.000000

Answer 1

Yes, the document says it was added in php5.2.2, but I found the same problem after testing and could only return 000000

But you can use this function: microtime()

Answer 2

I tested it locally.

• 7.0, showing ‘000000’

• 7.1, showing real data.
  So, are you sure the environment you are running the code in is 7.1?