DateTime::getTimestamp()

DateTimeImmutable::getTimestamp

DateTimeInterface::getTimestamp

date_timestamp_get

(PHP 5 >= 5.3.0, PHP 7)

Gets the Unix timestamp

说明

面向对象风格
publicDateTime::getTimestamp(void): int

publicDateTimeImmutable::getTimestamp(void): int

publicDateTimeInterface::getTimestamp(void): int

过程化风格
date_timestamp_get(DateTimeInterface$object): int

Gets the Unix timestamp.

参数

此函数没有参数。

返回值

Returns the Unix timestamp representing the date.

范例

Example #1DateTime::getTimestamp()example

面向对象风格

<?php
$date = new DateTime();
echo $date->getTimestamp();
?>

过程化风格

<?php
$date = date_create();
echo date_timestamp_get($date);
?>

以上例程的输出类似于：

1272509157

注释

UsingUas the parameter toDateTime::format()is an alternative when using PHP 5.2.

参见

• DateTime::setTimestamp() 以 Unix 时间戳的方式设置 DateTime 对象
• DateTime::format() Returns date formatted according to given format

In 32-bit system the unix timestamp will overflow if the date goes beyond year 2038 and this method will return false. In 64-bit systems this function will still work as intended. For more information please see http://en.wikipedia.org/wiki/Year_2038_problem.

Note that for dates before the unix epoch getTimestamp() will return false, whereas format("U") will return a negative number.
<?php
$date = new DateTime("1899-12-31");
// "-2209078800"
echo $date->format("U");
// false
echo $date->getTimestamp();
?>

Miguel's comment is wrong - getTimeStamp() always returns a timestamp, this has nothing to do with timezones at all, as you can see below.
What's really happening in Miguel's example, is he is parsing the input dates in different timezones.
There is no such thing as "a timestamp relative to the timezone".
<?php
$d = new DateTime('2016-03-11 11:00:00', new DateTimeZone('Europe/Rome'));
var_dump($d->getTimestamp()); // 1457690400
$d->setTimeZone(new DateTimeZone('America/New_York'));
var_dump($d->getTimestamp()); // 1457690400

Note that getTimestamp() does not return the UTC timestamp. It returns the timestamp relative to the set timezone, or the default server timezone. This also applies to dates in timezones with Daylight Savings.
<?php
// 11th March 2016 @ 11:00 UTC has timestamp: 1457694000
$d1 = new DateTime('2016-03-11 11:00:00', new DateTimeZone('Europe/Rome'));
$t1 = $d1->getTimestamp();
// 11th April 2016 @ 11:00 UTC has timestamp: 1460372400
$d2 = new DateTime('2016-04-11 11:00:00', new DateTimeZone('Europe/Rome'));
$t2 = $d2->getTimestamp();
printf("11 March: %d (diff = %d less)\n", $t1, 1457694000 - $t1);
printf("11 April: %d (diff = %d less)", $t2, 1460372400 - $t2);
// Prints:
// 1457690400 (diff = 3600)
// 1460365200 (diff = 7200)