Undefined date_diff() - php

Question

I'm trying to use date_diff():
$datetime1 = date_create('19.03.2010');
$datetime2 = date_create('22.04.2010');
$interval = date_diff($datetime1, $datetime2);
echo $interval->format('%R%d days');
Its doesn't work for me, gives an error:
Call to undefined function date_diff()
How can I get it work?
PHP 5.2 is used.
Thanks.

Answer 1

The function date_diff requires a PHP version of 5.3 or greater.
UPDATE
An example for PHP 5.2 (taken from the date_diff user comments).
<?php
function date_diff($date1, $date2) {
$current = $date1;
$datetime2 = date_create($date2);
$count = 0;
while(date_create($current) < $datetime2){
$current = gmdate("Y-m-d", strtotime("+1 day", strtotime($current)));
$count++;
}
return $count;
}
echo (date_diff('2010-3-9', '2011-4-10')." days <br \>");
?>

Answer 2

Here is a version that doesn't use Date objects, but these are of no use anyways in 5.2.
function date_diff($d1, $d2){
$d1 = (is_string($d1) ? strtotime($d1) : $d1);
$d2 = (is_string($d2) ? strtotime($d2) : $d2);
$diff_secs = abs($d1 - $d2);
return floor($diff_secs / (3600 * 24));
}

Answer 3

First convert both dates to mm/dd/yyyy format then do this :
$DateDiff = floor( strtotime($datetime2 ) - strtotime( $datetime1 ) ) / 86400 ;
//this will yield the resultant difference in days

Answer 4

function date_diff($date1, $date2) {
$count = 0;
//Ex 2012-10-01 and 2012-10-20
if(strtotime($date1) < strtotime($date2))
{
$current = $date1;
while(strtotime($current) < strtotime($date2)){
$current = date("Y-m-d",strtotime("+1 day", strtotime($current)));
$count++;
}
}
//Ex 2012-10-20 and 2012-10-01
else if(strtotime($date2) < strtotime($date1))
{
$current = $date2;
while(strtotime($current) < strtotime($date1)){
$current = date("Y-m-d",strtotime("+1 day", strtotime($current)));
$count++;
}
$current = $current * -1;
}
return $count; }

Answer 5

Converting your DateTime to Unix date type, and subtracting one from another:
The format->("U") is where the DateTime is converted.
$datetime1 = date_create('19.03.2010');
$datetime2 = date_create('22.04.2010');
$intervalInDays = ($datetime2->format("U") - $datetime1->format("U"))/(3600 * 24);
Not sure if this is Y2K38 safe but it's one of the simplest date_diff workarounds.