is_plugin_active( string $plugin ): bool
- Since
- 2.5.0
- Source
wp-admin/includes/plugin.php:539
Description
Only plugins installed in the plugins/ folder can be active.
Plugins in the mu-plugins/ folder can't be "activated," so this function will return false for those plugins.
For more information on this and similar theme functions, check out the https://developer.wordpress.org/themes/basics/conditional-tags/ Conditional Tags article in the Theme Developer Handbook.
Compatibility
- WordPress
- since 2.5.0
- 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
$pluginstring- Path to the plugin file relative to the plugins directory.
Return value
bool- True, if in the active plugins list. False, not in the list.
Performance profile
How much work a call to is_plugin_active() 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
- Scaling
- Constant
- Instructions
- 10–14
- Plugin surface
- None
- Called by
- 26
Reads stored settings via get_option(), cached per request but not free on a cold cache.
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 14.
Nothing here hands control to plugin code.
26 places in core call this, so the cost is paid more often than your own code shows.
What it touches
- optionoption read or write
get_option()called directly - hookthird-party callbacks
apply_filters()one call below is_plugin_active() - cacheobject cache
wp_cache_get()one call below is_plugin_active() - serializeserialisation
maybe_unserialize()one call below is_plugin_active()
Further down the call graph this can also reach 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 · 2 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost is_plugin_active() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
$plugin | 10 | get_option() |
!$plugin | 14 | get_option(), is_plugin_active_for_network() |
Across PHP versions
| PHP | Compiled | Executed | Branches | Notes |
|---|---|---|---|---|
| 8.6-dev | 14 | 10–14 | 1 | |
| 8.5 | 14 | 10–14 | 1 | |
| 8.4 | 14 | 10–14 | 1 | 3 fewer instructions than PHP 8.3 |
| 8.3 | 17 | 13–17 | 1 | |
| 8.2 | 17 | 13–17 | 1 | |
| 8.1 | 17 | 13–17 | 1 | |
| 7.4 | 17 | 13–17 | 1 |
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 · 2
- get_option()Retrieves an option value based on an option name.
- is_plugin_active_for_network()Determines whether the plugin is active for the entire network.
Used by · 26
- Plugin_Installer_Skin::after()Performs an action following a plugin install.
- Plugin_Upgrader::active_after()Turns off maintenance mode after upgrading an active plugin.
- Plugin_Upgrader::active_before()Turns on maintenance mode before attempting to background update an active plugin.
- Plugin_Upgrader::bulk_upgrade()Upgrades several plugins at once.
- Plugin_Upgrader::deactivate_plugin_before_upgrade()Deactivates a plugin before it is upgraded.
- Plugin_Upgrader_Skin::__construct()Constructor.
- WP_Automatic_Updater::update()Updates an item, if appropriate.
- WP_Debug_Data::get_wp_plugins_raw_data()Gets the raw plugin data for the WordPress active and inactive sections of the debug data.
- WP_Plugin_Dependencies::has_active_dependents()Determines whether the plugin has active dependents.
- WP_Plugins_List_Table::add_dependencies_to_dependent_plugin_row()Prints a list of other plugins that the plugin depends on.
- WP_Plugins_List_Table::prepare_items()
- WP_Plugins_List_Table::single_row()
Show all 26
- WP_REST_Plugins_Controller::check_read_permission()Checks if the given plugin can be viewed by the current user.
- WP_REST_Plugins_Controller::delete_item()Deletes one plugin from the site.
- WP_REST_Plugins_Controller::get_plugin_status()Get's the activation status for a plugin.
- WP_Site_Health::get_test_plugin_version()Tests if plugins are outdated, or unnecessary.
- deactivate_plugins()Deactivates a single plugin or multiple plugins.
- is_plugin_inactive()Determines whether the plugin is inactive.
- is_plugin_paused()Determines whether a plugin is technically active but was paused while loading.
- wp_ajax_activate_plugin()Handles activating a plugin via AJAX.
- wp_ajax_delete_plugin()Handles deleting a plugin via AJAX.
- wp_ajax_press_this_add_category()Ajax handler for creating new category from Press This.
- wp_ajax_press_this_save_post()Ajax handler for saving a post from Press This.
- wp_get_plugin_action_button()Gets the markup for the plugin install action button.
- wp_load_press_this()
- wp_plugin_update_row()Displays update information for a plugin.
Source code
function is_plugin_active( $plugin ) { return in_array( $plugin, (array) get_option( 'active_plugins', array() ), true ) || is_plugin_active_for_network( $plugin );}Changelog
Introduced in 2.5.0. 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-admin/includes/plugin.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.