(PHP 5 >= 5.5.0, PHP 7, PHP 8, PECL >= 3.0.0a1)
IntlCalendar::setFirstDayOfWeek — Set the day on which the week is deemed to start
Stile orientato agli oggetti
Stile procedurale
   Defines the day of week deemed to start the week. This affects the behavior
   of fields that depend on the concept of week start and end such as
   IntlCalendar::FIELD_WEEK_OF_YEAR and
   IntlCalendar::FIELD_YEAR_WOY.
  
calendarAn IntlCalendar instance.
dayOfWeek
      One of the constants IntlCalendar::DOW_SUNDAY,
      IntlCalendar::DOW_MONDAY, …,
      IntlCalendar::DOW_SATURDAY.
     
   Always returns true.
  
| Versione | Descrizione | 
|---|---|
| 8.2.0 | The return type is truenow; previously, it was bool. | 
Example #1 IntlCalendar::setFirstDayOfWeek()
<?php
ini_set('date.timezone', 'Europe/Lisbon');
ini_set('intl.default_locale', 'es_ES');
$cal = IntlCalendar::createInstance();
$cal->set(2013, 5 /* June */, 30); // A Sunday
var_dump($cal->getFirstDayOfWeek()); // 2 (Monday)
echo IntlDateFormatter::formatObject($cal, <<<EOD
'local day of week: 'cc'
week of month    : 'W'
week of year     : 'ww
EOD
), "\n";
$cal->setFirstDayOfWeek(IntlCalendar::DOW_SUNDAY);
echo IntlDateFormatter::formatObject($cal, <<<EOD
'local day of week: 'cc'
week of month    : 'W'
week of year     : 'ww
EOD
), "\n";Il precedente esempio visualizzerà:
int(2) local day of week: 7 week of month : 4 week of year : 26 local day of week: 1 week of month : 5 week of year : 27
