register_uninstall_hook( string $file, callable $callback )
- Since
- 2.7.0
- Source
wp-includes/plugin.php:934
Description
Registers the uninstall hook that will be called when the user clicks on the uninstall link that calls for the plugin to uninstall itself. The link won't be active unless the plugin hooks into the action.
The plugin should not run arbitrary code outside of functions, when registering the uninstall hook. In order to run using the hook, the plugin will have to be included, which means that any code laying outside of a function will be run during the uninstallation process. The plugin should not hinder the uninstallation process.
If the plugin can not be written without running code within the plugin, then the plugin should create a file named 'uninstall.php' in the base plugin folder. This file will be called, if it exists, during the uninstallation process bypassing the uninstall hook. The plugin, when using the 'uninstall.php' should always check for the 'WP_UNINSTALL_PLUGIN' constant, before executing.
Compatibility
- WordPress
- since 2.7.0
- 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
$filestring- Plugin file.
$callbackcallable- The callback to run when the hook is called. Must be a static method or function.
Performance profile
How much work a call to register_uninstall_hook() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.
- Cost class
- Moderate
- Scaling
- Constant
- Instructions
- 16–27
- Plugin surface
- None
- Called by
- 0
Reads stored settings via get_option(), cached per request but not free on a cold cache.
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 36.
Nothing here hands control to plugin code.
Nothing in core calls this; the cost is only what you spend yourself.
What it touches
- optionoption read or write
get_option()called directly - hookthird-party callbacks
do_action()one call below register_uninstall_hook() - cacheobject cache
wp_cache_get()one call below register_uninstall_hook() - serializeserialisation
maybe_unserialize()one call below register_uninstall_hook()
Further down the call graph this can also reach query and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.
What one call costs · 3 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost register_uninstall_hook() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
is_array($callback) | 16 | __(), _doing_it_wrong() |
isset($uninstallable_plugins[$plugin_basename]) && $callback === false | 18–21 | get_option(), plugin_basename() |
| always | 21–27 | get_option(), plugin_basename(), update_option() |
Across PHP versions
Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 36 instructions, 16–27 executed per call, 4 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 · 5
- _doing_it_wrong()Marks something as being incorrectly called.
- __()Retrieves the translation of $text.
- get_option()Retrieves an option value based on an option name.
- plugin_basename()Gets the basename of a plugin.
- update_option()Updates the value of an option that was already added.
Source code
function register_uninstall_hook( $file, $callback ) { if ( is_array( $callback ) && is_object( $callback[0] ) ) { _doing_it_wrong( __FUNCTION__, __( 'Only a static class method or function can be used in an uninstall hook.' ), '3.1.0' ); return; } /* * The option should not be autoloaded, because it is not needed in most * cases. Emphasis should be put on using the 'uninstall.php' way of * uninstalling the plugin. */ $uninstallable_plugins = (array) get_option( 'uninstall_plugins' ); $plugin_basename = plugin_basename( $file ); if ( ! isset( $uninstallable_plugins[ $plugin_basename ] ) || $uninstallable_plugins[ $plugin_basename ] !== $callback ) { $uninstallable_plugins[ $plugin_basename ] = $callback; update_option( 'uninstall_plugins', $uninstallable_plugins ); }}Changelog
Introduced in 2.7.0. 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 7.1.0 tag, from
src/wp-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.