What can use for DateTime::diff() for PHP 5.2?

Spudley's answer doesn't work for me--subtracting any DateTime from another gives 0 on my system.

I was able to get it to work by using DateTime::format with the 'U' specifier (seconds since Unix epoch):

$start = new DateTime('2010-10-12');$end = new DateTime();$days = round(($end->format('U') - $start->format('U')) / (60*60*24));

This works on both my dev system (5.3.4) and my deployment system (5.2.11).

I just needed that ( unfortunately ) for a WordPress plugin. This I use the function in 2 times:

1. In my class calling ->diff() ( my class extends DateTime, so $this is the reference DateTime )

   function diff ($secondDate){    $firstDateTimeStamp = $this->format("U");    $secondDateTimeStamp = $secondDate->format("U");    $rv = ($secondDateTimeStamp - $firstDateTimeStamp);    $di = new DateInterval($rv);    return $di;}

2. Then I recreated a fake DateInterval class ( because DateInterval is only valid in PHP >= 5.3 ) as follows:

   Class DateInterval {    /* Properties */    public $y = 0;    public $m = 0;    public $d = 0;    public $h = 0;    public $i = 0;    public $s = 0;    /* Methods */    public function __construct ( $time_to_convert /** in seconds */) {        $FULL_YEAR = 60*60*24*365.25;        $FULL_MONTH = 60*60*24*(365.25/12);        $FULL_DAY = 60*60*24;        $FULL_HOUR = 60*60;        $FULL_MINUTE = 60;        $FULL_SECOND = 1;//        $time_to_convert = 176559;        $seconds = 0;        $minutes = 0;        $hours = 0;        $days = 0;        $months = 0;        $years = 0;        while($time_to_convert >= $FULL_YEAR) {            $years ++;            $time_to_convert = $time_to_convert - $FULL_YEAR;        }        while($time_to_convert >= $FULL_MONTH) {            $months ++;            $time_to_convert = $time_to_convert - $FULL_MONTH;        }        while($time_to_convert >= $FULL_DAY) {            $days ++;            $time_to_convert = $time_to_convert - $FULL_DAY;        }        while($time_to_convert >= $FULL_HOUR) {            $hours++;            $time_to_convert = $time_to_convert - $FULL_HOUR;        }        while($time_to_convert >= $FULL_MINUTE) {            $minutes++;            $time_to_convert = $time_to_convert - $FULL_MINUTE;        }        $seconds = $time_to_convert; // remaining seconds        $this->y = $years;        $this->m = $months;        $this->d = $days;        $this->h = $hours;        $this->i = $minutes;        $this->s = $seconds;    }}

Hope that helps somebody.

I use this, seems to work alright - obviously you can add a second parameter to make it more flexible:

function GetDateDiffFromNow($originalDate) {    $unixOriginalDate = strtotime($originalDate);    $unixNowDate = strtotime('now');    $difference = $unixNowDate - $unixOriginalDate ;    $days = (int)($difference / 86400);    $hours = (int)($difference / 3600);    $minutes = (int)($difference / 60);    $seconds = $difference;    // now do what you want with this now and return ...}