date_default_timezone_get

(PHP 5 >= 5.1.0, PHP 7, PHP 8)

date_default_timezone_get — 取得一个脚本中所有日期时间函数所使用的默认时区

说明

date_default_timezone_get ( ) : string

本函数返回默认时区，使用如下"假定"的顺序：

  • 用 date_default_timezone_set() 函数设定的时区（如果设定了的话）

  • 仅仅在 PHP 5.4.0 之前： TZ 环境变量（如果非空）

  • date.timezone 配置选项（如果设定了的话）

  • 仅仅在 PHP 5.4.0 之前： 查询操作系统主机 (如果操作系统支持并允许)。 This uses an algorithm that has to guess the timezone. This is by no means going to work correctly for every situation. A warning is shown when this stage is reached. Do not rely on it to be guessed correctly, and set date.timezone to the correct timezone instead.

  • 如果以上选择都不成功，date_default_timezone_get() 会则返回 UTC 的默认时区。

返回值

返回一个 string。

更新日志

版本 说明
5.4.0 不再使用 TZ 来推测时区。
5.4.0 不再根据操作系统的信息来推测时区，因为这是不可靠的。

范例

Example #1 获取默认时区

<?php
date_default_timezone_set('Europe/London');

if (date_default_timezone_get()) {
    echo 'date_default_timezone_set: ' . date_default_timezone_get() . '<br />';
}

if (ini_get('date.timezone')) {
    echo 'date.timezone: ' . ini_get('date.timezone');
}

?>

以上例程的输出类似于：

date_default_timezone_set: Europe/London
date.timezone: Europe/London

Example #2 获取一个时区的简写

<?php
date_default_timezone_set('America/Los_Angeles');
echo date_default_timezone_get() . ' => ' . date('e') . ' => ' . date('T');
?>

以上例程会输出：

America/Los_Angeles => America/Los_Angeles => PST

参见

User Contributed Notes

smcbride at msn dot com 24-Dec-2020 02:09
This function is not very useful for getting the OS timezone.  One way to do it is to look at the results of 'timedatectl' from the OS.  You can also look at the link from /etc/localtime

>file /etc/localtime
/etc/localtime: symbolic link to /usr/share/zoneinfo/America/Los_Angeles

>timedatectl
               Local time: Thu 2020-12-24 07:11:27 PST    
           Universal time: Thu 2020-12-24 15:11:27 UTC    
                 RTC time: Thu 2020-12-24 15:11:27        
                Time zone: America/Los_Angeles (PST, -0800)
System clock synchronized: yes                            
              NTP service: active                         
          RTC in local TZ: no

<?php

$dateinfo = trim(shell_exec("timedatectl | grep -i zone: 2>/dev/null"));
$dateinfoarray = explode(' ', $dateinfo);
echo 'Timezone = ' . $dateinfoarray[2] . PHP_EOL;

?>
andrea at -REMOVE- bhweb dot it 22-Jul-2015 05:21
Please note that "Damien dot Garrido dot Work at gmail dot com" code is wrong, the third parameter of sprintf must be divided by 60.

This is the corrected function:

<?php
function timezone_offset_string( $offset )
{
        return sprintf( "%s%02d:%02d", ( $offset >= 0 ) ? '+' : '-', abs( $offset / 3600 ), abs( $offset % 3600 ) / 60 );
}
?>
bohwaz 12-Sep-2013 03:23
Please note that on Debian/Ubuntu this function will return the system timezone defined in /etc/localtime if date.timezone is not defined, even with PHP 5.4+

See http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=673763#10
benrwhite at gmail dot com 12-Jul-2013 11:31
For the reason that date_default_timezone_get() throws an error when the timezone isn't set in php.ini and then returns a default chosen by the system (rather than returning false to indicate to the script that a timezone hasn't been set), I've found that the following works when you want a script to detect when the ini value has not been set and want the script itself to choose a default in that case, while still allowing bootstrap scripts to set their own default using date_default_timezone_set().

<?php

set_error_handler(function ($errno, $errstr){
    throw new Exception($errstr);
    return false;
});
try{
    date_default_timezone_get();
}
catch(Exception $e){
    date_default_timezone_set('UTC'); // Sets to UTC if not specified anywhere in .ini
}
restore_error_handler();
Damien dot Garrido dot Work at gmail dot com 05-Jul-2012 12:04
To get offset string from offset:

<?php

function timezone_offset_string( $offset )
{
        return sprintf( "%s%02d:%02d", ( $offset >= 0 ) ? '+' : '-', abs( $offset / 3600 ), abs( $offset % 3600 ) );
}

$offset = timezone_offset_get( new DateTimeZone( 'Pacific/Kiritimati' ), new DateTime() );
echo "offset: " . timezone_offset_string( $offset ) . "\n";

$offset = timezone_offset_get( new DateTimeZone( 'Pacific/Tahiti' ), new DateTime() );
echo "offset: " . timezone_offset_string( $offset ) . "\n";
?>

Output:
offset: +14:00
offset: -10:00
glennpratt+php at gmail dot com 19-May-2011 01:30
In my case, I'm not sure I can guess the correct timezone any better than PHP and it's no where near important enough to nag the user, so...

<?php
// Suppress DateTime warnings
date_default_timezone_set(@date_default_timezone_get());
?>
harmor 28-Feb-2008 08:19
If you want to get the abbrivation (3 or 4 letter), instead of the long timezone string you can use date('T') function like this:

Input:
date_default_timezone_set('America/Los_Angeles');
echo date_default_timezone_get();
echo ' => '.date('e');
echo ' => '.date('T');

Output:
America/Los_Angeles => America/Los_Angeles => PST
dohpaz at gmail dot com 20-Apr-2007 02:58
date_default_timezone_get() will still emit a warning in E_STRICT if the timezone is not set; either by date_default_timezone_set() or the ini option of date.timezone.

This is probably not a big deal, but I thought I would contribute what I found.