# IntlCalendar::fieldDifference

(PHP 5 >= 5.5.0, PHP 7, PECL >= 3.0.0a1)

IntlCalendar::fieldDifference — Calculate difference between given time and this objectʼs time

### Description

Object oriented style

public IntlCalendar::fieldDifference ( float `$when` , int `$field` ) : int|false

Procedural style

intlcal_field_difference ( IntlCalendar `$cal` , float `$when` , int `$field` ) : int|false

Return the difference between the given time and the time this object is set to, with respect to the quantity specified the `field` parameter.

This method is meant to be called successively, first with the most significant field of interest down to the least significant field. To this end, as a side effect, this calendarʼs value for the field specified is advanced by the amount returned.

### Parameters

`cal`

  The IntlCalendar resource.

`when`

  The time against which to compare the quantity represented by the `field`. For the result to be positive, the time given for this parameter must be ahead of the time of the object the method is being invoked on.

`field`

  The field that represents the quantity being compared.

  One of the IntlCalendar date/time field constants. These are integer values between `0` and `IntlCalendar::FIELD_COUNT`.

### Return Values

Returns a (signed) difference of time in the unit associated with the specified field or `FALSE` on failure.

### Examples

Example #1 IntlCalendar::fieldDifference()

`<?php
ini_set('date.timezone', 'Europe/Lisbon');
ini_set('intl.default_locale', 'fr_FR');
$cal1 = IntlCalendar::fromDateTime('2012-02-29 09:00:11');
$cal2 = IntlCalendar::fromDateTime('2013-03-01 09:19:29');
$time = $cal2->getTime();
echo "Time before: ", IntlDateFormatter::formatObject($cal1), "\n";
printf(
"The difference in time is %d year(s), %d month(s), "
. "%d day(s), %d hour(s) and %d minute(s)\n",
$cal1->fieldDifference($time, IntlCalendar::FIELD_YEAR),
$cal1->fieldDifference($time, IntlCalendar::FIELD_MONTH),
$cal1->fieldDifference($time, IntlCalendar::FIELD_DAY_OF_MONTH),
$cal1->fieldDifference($time, IntlCalendar::FIELD_HOUR_OF_DAY),
$cal1->fieldDifference($time, IntlCalendar::FIELD_MINUTE)
);
//now it was advanced to the target time, exception for the seconds,
//for which we did not measure the difference
echo "Time after: ", IntlDateFormatter::formatObject($cal1), "\n";`

The above example will output:

    Time before: 29 févr. 2012 09:00:11
    The difference in time is 1 year(s), 0 month(s), 1 day(s), 0 hour(s) and 19 minute(s)
    Time after: 1 mars 2013 09:19:11