+ * 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 uninstall process. The plugin should not
+ * hinder the uninstall 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 uninstall process
+ * bypassing the uninstall hook. The plugin, when using the 'uninstall.php'
+ * should always check for the 'WP_UNINSTALL_PLUGIN' constant, before
+ * executing.
+ *
+ * @since 2.7
+ *
+ * @param string $file
+ * @param callback $callback The callback to run when the hook is called.
+ */
+function register_uninstall_hook($file, $callback) {
+ // 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');
+ $uninstallable_plugins[plugin_basename($file)] = $callback;
+ update_option('uninstall_plugins', $uninstallable_plugins);
+}
+
+/**
+ * Calls the 'all' hook, which will process the functions hooked into it.
+ *
+ * The 'all' hook passes all of the arguments or parameters that were used for
+ * the hook, which this function was called for.
+ *
+ * This function is used internally for apply_filters(), do_action(), and
+ * do_action_ref_array() and is not meant to be used from outside those
+ * functions. This function does not check for the existence of the all hook, so
+ * it will fail unless the all hook exists prior to this function call.