Add a (signed) amount of time to a field

# IntlCalendar::add

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

IntlCalendar::add — Add a (signed) amount of time to a field

### 説明

オブジェクト指向型

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

手続き型

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

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.

### パラメータ

`cal`

  The IntlCalendar resource.

`field`

  IntlCalendar の日付/時刻 フィールド定数 のいずれか。 0 から `IntlCalendar::FIELD_COUNT` までの間の整数値です。

`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`.

### 返り値

Returns `TRUE` on success失敗した場合に `FALSE` を返します.

### 例

例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";`

上の例の出力は以下となります。

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