load_default_textdomain( string $locale = null ): bool
- Since
- 1.5.0
- Source
wp-includes/l10n.php:951
Loads default translated strings based on locale.
Description
Loads the .mo file in WP_LANG_DIR constant path from WordPress root.
The translated (.mo) file is named based on the locale.
Compatibility
- WordPress
- since 1.5.0
- 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
$localestringoptional- Locale to load. Default is the value of get_locale().Default:
null
Return value
bool- Whether the textdomain was loaded.
Performance profile
How much work a call to load_default_textdomain() 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
- Heavy
- Scaling
- Constant
- Instructions
- 37–75
- Plugin surface
- None
- Called by
- 3
Reads or writes the filesystem via file_exists().
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 86.
Nothing here hands control to plugin code.
3 places in core call this, so the cost is paid more often than your own code shows.
What it touches
- filesystemfilesystem access
file_exists()called directly - hookthird-party callbacks
apply_filters()one call below load_default_textdomain()
Further down the call graph this can also reach query, option, cache, serialize 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 · 26 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost load_default_textdomain() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
$locale !== null && !is_multisite() && !is_admin() && !wp_installing() && !is_network_admin() | 37–43 | unload_textdomain(), load_textdomain(), is_multisite(), is_admin(), wp_installing(), is_network_admin() |
$locale === null && !is_multisite() && !is_admin() && !wp_installing() && !is_network_admin() | 40–46 | determine_locale(), unload_textdomain(), load_textdomain(), is_multisite(), is_admin(), wp_installing(), is_network_admin() |
$locale !== null && !file_exists() | 41–45 | unload_textdomain(), load_textdomain(), is_multisite(), file_exists(), load_textdomain() |
$locale !== null && !is_multisite() && is_admin() && !is_network_admin() | 42–46 | unload_textdomain(), load_textdomain(), is_multisite(), is_admin(), load_textdomain(), is_network_admin() |
$locale === null && !file_exists() | 44–48 | determine_locale(), unload_textdomain(), load_textdomain(), is_multisite(), file_exists(), load_textdomain() |
$locale !== null && file_exists() && !is_admin() && !wp_installing() && !is_network_admin() | 44–52 | unload_textdomain(), load_textdomain(), is_multisite(), file_exists(), is_admin(), wp_installing(), is_network_admin() |
$locale !== null && !is_multisite() && !is_admin() && !is_network_admin() | 45–53 | unload_textdomain(), load_textdomain(), is_multisite(), is_admin(), wp_installing(), load_textdomain(), is_network_admin() |
$locale !== null && !is_multisite() && !is_admin() && !wp_installing() | 45–53 | unload_textdomain(), load_textdomain(), is_multisite(), is_admin(), wp_installing(), is_network_admin(), load_textdomain() |
$locale === null && !is_multisite() && is_admin() && !is_network_admin() | 45–49 | determine_locale(), unload_textdomain(), load_textdomain(), is_multisite(), is_admin(), load_textdomain(), is_network_admin() |
$locale === null && file_exists() && !is_admin() && !wp_installing() && !is_network_admin() | 47–55 | determine_locale(), unload_textdomain(), load_textdomain(), is_multisite(), file_exists(), is_admin(), wp_installing(), is_network_admin() |
$locale === null && !is_multisite() && !is_admin() && !is_network_admin() | 48–56 | determine_locale(), unload_textdomain(), load_textdomain(), is_multisite(), is_admin(), wp_installing(), load_textdomain(), is_network_admin() |
$locale === null && !is_multisite() && !is_admin() && !wp_installing() | 48–56 | determine_locale(), unload_textdomain(), load_textdomain(), is_multisite(), is_admin(), wp_installing(), is_network_admin(), load_textdomain() |
14 further outcomes, up to 75 instructions
$locale !== null && file_exists() && is_admin() && !is_network_admin() | 49–55 | unload_textdomain(), load_textdomain(), is_multisite(), file_exists(), is_admin(), load_textdomain(), is_network_admin() |
$locale !== null && !is_multisite() && is_admin() | 50–56 | unload_textdomain(), load_textdomain(), is_multisite(), is_admin(), load_textdomain(), is_network_admin(), load_textdomain() |
$locale !== null && file_exists() && !is_admin() && !is_network_admin() | 52–62 | unload_textdomain(), load_textdomain(), is_multisite(), file_exists(), is_admin(), wp_installing(), load_textdomain(), is_network_admin() |
$locale !== null && file_exists() && !is_admin() && !wp_installing() | 52–62 | unload_textdomain(), load_textdomain(), is_multisite(), file_exists(), is_admin(), wp_installing(), is_network_admin(), load_textdomain() |
$locale === null && file_exists() && is_admin() && !is_network_admin() | 52–58 | determine_locale(), unload_textdomain(), load_textdomain(), is_multisite(), file_exists(), is_admin(), load_textdomain(), is_network_admin() |
$locale !== null && !is_multisite() && !is_admin() | 53–63 | unload_textdomain(), load_textdomain(), is_multisite(), is_admin(), wp_installing(), load_textdomain(), is_network_admin(), load_textdomain() |
$locale === null && !is_multisite() && is_admin() | 53–59 | determine_locale(), unload_textdomain(), load_textdomain(), is_multisite(), is_admin(), load_textdomain(), is_network_admin(), load_textdomain() |
$locale === null && file_exists() && !is_admin() && !is_network_admin() | 55–65 | determine_locale(), unload_textdomain(), load_textdomain(), is_multisite(), file_exists(), is_admin(), wp_installing(), load_textdomain(), is_network_admin() |
$locale === null && file_exists() && !is_admin() && !wp_installing() | 55–65 | determine_locale(), unload_textdomain(), load_textdomain(), is_multisite(), file_exists(), is_admin(), wp_installing(), is_network_admin(), load_textdomain() |
$locale === null && !is_multisite() && !is_admin() | 56–66 | determine_locale(), unload_textdomain(), load_textdomain(), is_multisite(), is_admin(), wp_installing(), load_textdomain(), is_network_admin(), load_textdomain() |
$locale !== null && file_exists() && is_admin() | 57–65 | unload_textdomain(), load_textdomain(), is_multisite(), file_exists(), is_admin(), load_textdomain(), is_network_admin(), load_textdomain() |
$locale !== null && file_exists() && !is_admin() | 60–72 | unload_textdomain(), load_textdomain(), is_multisite(), file_exists(), is_admin(), wp_installing(), load_textdomain(), is_network_admin(), load_textdomain() |
$locale === null && file_exists() && is_admin() | 60–68 | determine_locale(), unload_textdomain(), load_textdomain(), is_multisite(), file_exists(), is_admin(), load_textdomain(), is_network_admin(), load_textdomain() |
$locale === null && file_exists() && !is_admin() | 63–75 | determine_locale(), unload_textdomain(), load_textdomain(), is_multisite(), file_exists(), is_admin(), wp_installing(), load_textdomain(), is_network_admin(), load_textdomain() |
Across PHP versions
Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 86 instructions, 37–75 executed per call, 12 branches. The work does not change between versions.
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.
Uses · 7
- determine_locale()Determines the current locale desired for the request.
- unload_textdomain()Unloads translations for a text domain.
- load_textdomain()Loads a .mo file into the text domain $domain.
- is_multisite()Determines whether Multisite is enabled.
- is_admin()Determines whether the current request is for an administrative interface page.
- wp_installing()Checks or sets whether WordPress is in "installation" mode.
- is_network_admin()Determines whether the current request is for the network administrative interface.
Used by · 3
- WP_Fatal_Error_Handler::handle()Runs the shutdown handler.
- WP_Locale_Switcher::load_translations()Load translations for a given locale.
- _redirect_to_about_wordpress()Redirect to the About WordPress page after a successful upgrade.
Source code
function load_default_textdomain( $locale = null ) { if ( null === $locale ) { $locale = determine_locale(); } // Unload previously loaded strings so we can switch translations. unload_textdomain( 'default', true ); $return = load_textdomain( 'default', WP_LANG_DIR . "/$locale.mo", $locale ); if ( ( is_multisite() || ( defined( 'WP_INSTALLING_NETWORK' ) && WP_INSTALLING_NETWORK ) ) && ! file_exists( WP_LANG_DIR . "/admin-$locale.mo" ) ) { load_textdomain( 'default', WP_LANG_DIR . "/ms-$locale.mo", $locale ); return $return; } if ( is_admin() || wp_installing() || ( defined( 'WP_REPAIRING' ) && WP_REPAIRING ) ) { load_textdomain( 'default', WP_LANG_DIR . "/admin-$locale.mo", $locale ); } if ( is_network_admin() || ( defined( 'WP_INSTALLING_NETWORK' ) && WP_INSTALLING_NETWORK ) ) { load_textdomain( 'default', WP_LANG_DIR . "/admin-network-$locale.mo", $locale ); } return $return;}Changelog
Introduced in 1.5.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
About this page
- Parsed data
- Generated from the wordpress-develop 6.7.7 tag, from
src/wp-includes/l10n.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it. - Corrections
- Something wrong on this page? Report it and it gets fixed in the next regeneration.