<?php

ini_set("intl.error_level", E_WARNING);
ini_set("intl.default_locale", "nl");
date_default_timezone_set('Europe/Amsterdam');
$intlcal = new IntlGregorianCalendar();
var_dump($intlcal->isLeapYear(2012));
var_dump($intlcal->isLeapYear(1900));
var_dump(intlgregcal_is_leap_year($intlcal, 2012));
var_dump(intlgregcal_is_leap_year($intlcal, 1900));
?>
==DONE==
<?php

ini_set("intl.error_level", E_WARNING);
$c = new IntlGregorianCalendar(NULL, 'pt_PT');
var_dump($c->isLeapYear(2000, 2011));
var_dump($c->isLeapYear());
var_dump($c->isLeapYear("fgdf"));
var_dump(intlgregcal_is_leap_year($c, 1, 2));
var_dump(intlgregcal_is_leap_year($c));
var_dump(intlgregcal_is_leap_year(1, 2));