XXI. Date and Time Functions

Introduction

These functions allow you to get the date and time from the server where your PHP scripts are running. You can use these functions to format the date and time in many different ways.

Note: Please keep in mind that these functions are dependent on the locale settings of your server. Make sure to take daylight saving time (use e.g. $date = strtotime('+7 days', $date) and not $date += 7*24*60*60) and leap years into consideration when working with these functions.

Note: The timezones referenced in this section can be found in the Appendix H.

Requirements

No external libraries are needed to build this extension.

Installation

There is no installation needed to use these functions; they are part of the PHP core.

Note: The latest version of the timezone database can be installed via PECL's timezonedb. For Windows users, a pre-compiled DLL can be downloaded from the PECL4Win site: php_timezonedb.dll.

Runtime Configuration

This extension has no configuration directives defined in php.ini.

Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

Table 1. Date/Time Configuration Options

Name	Default	Changeable	Changelog
date.default_latitude	"31.7667"	PHP_INI_ALL	Available since PHP 5.0.0.
date.default_longitude	"35.2333"	PHP_INI_ALL	Available since PHP 5.0.0.
date.sunrise_zenith	"90.83"	PHP_INI_ALL	Available since PHP 5.0.0.
date.sunset_zenith	"90.83"	PHP_INI_ALL	Available since PHP 5.0.0.
date.timezone	""	PHP_INI_ALL	Available since PHP 5.1.0.

For further details and definitions of the PHP_INI_* constants, see the Appendix G.

Here's a short explanation of the configuration directives.

date.default_latitude float: The default latitude.
date.default_longitude float: The default longitude.
date.sunrise_zenith float: The default sunrise zenith.
date.sunset_zenith float: The default sunset zenith.
date.timezone string: The default timezone used by all date/time functions if the TZ environment variable isn't set. The precedence order is described in the date_default_timezone_get() page. See Appendix H for a list of supported timezones.

Note: The first four configuration options are currently only used by date_sunrise() and date_sunset().

Resource Types

This extension has no resource types defined.

Predefined Constants

The following constants are defined since PHP 5.1.1 and they offer standard date representations, which can be used along with the date format functions (like date()).

DATE_ATOM (string): Atom (example: 2005-08-15T15:52:01+00:00)
DATE_COOKIE (string): HTTP Cookies (example: Monday, 15-Aug-05 15:52:01 UTC)
DATE_ISO8601 (string): ISO-8601 (example: 2005-08-15T15:52:01+0000)
DATE_RFC822 (string): RFC 822 (example: Mon, 15 Aug 05 15:52:01 +0000)
DATE_RFC850 (string): RFC 850 (example: Monday, 15-Aug-05 15:52:01 UTC)
DATE_RFC1036 (string): RFC 1036 (example: Mon, 15 Aug 05 15:52:01 +0000)
DATE_RFC1123 (string): RFC 1123 (example: Mon, 15 Aug 2005 15:52:01 +0000)
DATE_RFC2822 (string): RFC 2822 (Mon, 15 Aug 2005 15:52:01 +0000)
DATE_RSS (string): RSS (Mon, 15 Aug 2005 15:52:01 +0000)
DATE_W3C (string): World Wide Web Consortium (example: 2005-08-15T15:52:01+00:00)

Table of Contents
checkdate -- Validate a Gregorian date
date_default_timezone_get -- Gets the default timezone used by all date/time functions in a script
date_default_timezone_set -- Sets the default timezone used by all date/time functions in a script
date_sunrise -- Returns time of sunrise for a given day and location
date_sunset -- Returns time of sunset for a given day and location
date -- Format a local time/date
getdate -- Get date/time information
gettimeofday -- Get current time
gmdate -- Format a GMT/UTC date/time
gmmktime -- Get Unix timestamp for a GMT date
gmstrftime -- Format a GMT/UTC time/date according to locale settings
idate -- Format a local time/date as integer
localtime -- Get the local time
microtime -- Return current Unix timestamp with microseconds
mktime -- Get Unix timestamp for a date
strftime -- Format a local time/date according to locale settings
strptime -- Parse a time/date generated with strftime()
strtotime -- Parse about any English textual datetime description into a Unix timestamp
time -- Return current Unix timestamp