PHP Manual: Add a (signed) amount of time to a field

Description

Object oriented style

public bool IntlCalendar::add ( int $field , int $amount )

Procedural style

bool intlcal_add ( IntlCalendar $cal , int $field , int $amount )

Add a signed amount to a field. Adding a positive amount allows advances in time, even if the numeric value of the field decreases (e.g. when working with years in BC dates).

Other fields may need to adjusted – for instance, adding a month to the 31st of January will result in the 28th (or 29th) of February. Contrary to IntlCalendar::roll, when a value wraps around, more significant fields may change. For instance, adding a day to the 31st of January will result in the 1st of February, not the 1st of Janurary.

Parameters

cal: The IntlCalendar resource.
field: One of the IntlCalendar date/time field constants. These are integer values between 0 and IntlCalendar::FIELD_COUNT.
amount: The signed amount to add to the current field. If the amount is positive, the instant will be moved forward; if it is negative, the instant wil be moved into the past. The unit is implicit to the field type. For instance, hours for IntlCalendar::FIELD_HOUR_OF_DAY.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example #1 IntlCalendar::add


<?php
ini_set('intl.default_locale', 'fr_FR');
ini_set('date.timezone', 'UTC');

$cal = new IntlGregorianCalendar(2012, 0 /* January */, 31);
echo IntlDateFormatter::formatObject($cal), "\n";

$cal->add(IntlCalendar::FIELD_MONTH, 1);
echo IntlDateFormatter::formatObject($cal), "\n";

$cal->add(IntlCalendar::FIELD_DAY_OF_MONTH, 1);
echo IntlDateFormatter::formatObject($cal), "\n";

The above example will output:

31 janv. 2012 00:00:00
29 févr. 2012 00:00:00
1 mars 2012 00:00:00