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WordPress

date_i18n( string $format, int|bool $timestamp_with_offset = false, bool $gmt = false ): string

Since
0.71, 5.3.0
Source
wp-includes/functions.php:179
Retrieves the date in localized format, based on a sum of Unix timestamp and timezone offset in seconds.

Description

If the locale specifies the locale month and weekday, then the locale will take over the format for the date. If it isn't, then the date format string will be used instead.

Note that due to the way WP typically generates a sum of timestamp and offset with strtotime(), it implies offset added at a current time, not at the time the timestamp represents. Storing such timestamps or calculating them differently will lead to invalid output.

Compatibility

WordPress
since 5.3.0
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$formatstring
Format to display the date.
$timestamp_with_offsetint|booloptional
A sum of Unix timestamp and timezone offset in seconds. Default false.Default: false
$gmtbooloptional
Whether to use GMT timezone. Only applies if timestamp is not provided. Default false.Default: false

Return value

string
The date, translated if locale specifies it.

Performance profile

How much work a call to date_i18n() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class
Moderate

Reads stored settings via get_option(), cached per request but not free on a cold cache.

Scaling
Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions
19–48

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 65.

Plugin surface
1 hook

Third-party callbacks on 'date_i18n' run inside this call, and their cost is not bounded by anything here.

Called by
22

22 places in core call this, so the cost is paid more often than your own code shows.

What it touches

  • hookthird-party callbacksapply_filters()called directly
  • optionoption read or writeget_option()one call below date_i18n()

Further down the call graph this can also reach cache, serialize, query and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 6 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost date_i18n() can have, taken from its control-flow graph on PHP 8.5.

WhenInstructionsCalls it makes
$timestamp && $format === "U"19apply_filters()
!$timestamp && $format === "U"24current_time(), apply_filters()
$timestamp && $format !== "U" && $timestamp_with_offset === false25–30wp_date(), apply_filters()
!$timestamp && $format !== "U" && $timestamp_with_offset === false30–35current_time(), wp_date(), apply_filters()
$timestamp && $format !== "U" && $timestamp_with_offset !== false41–43gmdate(), wp_timezone(), date_create(), ->getTimestamp(), wp_date(), apply_filters()
!$timestamp && $format !== "U" && $timestamp_with_offset !== false46–48current_time(), gmdate(), wp_timezone(), date_create(), ->getTimestamp(), wp_date(), apply_filters()

Across PHP versions

PHPCompiledExecutedBranchesNotes
8.6-dev6519–485
8.56519–485
8.46519–4852 fewer instructions than PHP 8.3
8.36721–505
8.26721–505
8.16721–505
7.46721–505

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Hooks and filters fired · 1

One hook fires while date_i18n() runs, in this order:

  1. apply_filters( date_i18n )filterline 220 (+41 into the body)

    Filters the date formatted based on the locale.

Uses · 5

  • current_time()Retrieves the current time based on specified type.
  • wp_date()Retrieves the date, in localized format.
  • wp_timezone()Retrieves the timezone of the site as a `DateTimeZone` object.
  • apply_filters()Calls the callback functions that have been added to a filter hook.
  • DateTimeZone::__construct()

Used by · 22

Show all 22

Source code

function date_i18n( $format, $timestamp_with_offset = false, $gmt = false ) {	$timestamp = $timestamp_with_offset; 	// If timestamp is omitted it should be current time (summed with offset, unless `$gmt` is true).	if ( ! is_numeric( $timestamp ) ) {		// phpcs:ignore WordPress.DateTime.CurrentTimeTimestamp.Requested		$timestamp = current_time( 'timestamp', $gmt );	} 	/*	 * This is a legacy implementation quirk that the returned timestamp is also with offset.	 * Ideally this function should never be used to produce a timestamp.	 */	if ( 'U' === $format ) {		$date = $timestamp;	} elseif ( $gmt && false === $timestamp_with_offset ) { // Current time in UTC.		$date = wp_date( $format, null, new DateTimeZone( 'UTC' ) );	} elseif ( false === $timestamp_with_offset ) { // Current time in site's timezone.		$date = wp_date( $format );	} else {		/*		 * Timestamp with offset is typically produced by a UTC `strtotime()` call on an input without timezone.		 * This is the best attempt to reverse that operation into a local time to use.		 */		$local_time = gmdate( 'Y-m-d H:i:s', $timestamp );		$timezone   = wp_timezone();		$datetime   = date_create( $local_time, $timezone );		$date       = wp_date( $format, $datetime->getTimestamp(), $timezone );	} 	/**	 * Filters the date formatted based on the locale.	 *	 * @since 2.8.0	 *	 * @param string $date      Formatted date string.	 * @param string $format    Format to display the date.	 * @param int    $timestamp A sum of Unix timestamp and timezone offset in seconds.	 *                          Might be without offset if input omitted timestamp but requested GMT.	 * @param bool   $gmt       Whether to use GMT timezone. Only applies if timestamp was not provided.	 */	$date = apply_filters( 'date_i18n', $date, $format, $timestamp, $gmt ); 	return $date;}

Changelog

Introduced in 0.71. Unchanged from 6.7.7 through 7.1.0.

  1. 6.7.7
  2. 6.8.8
  3. 6.9.7
  4. 7.0.4
  5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

5.3.0
Converted into a wrapper for wp_date().from the docblock
0.71
Introduced.from the docblock

About this page

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Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/functions.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
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