A

__autoload() – Autoloader compatibility callback.

__clear_multi_author_cache() – Helper function to clear the cache for number of authors.

__return_empty_array() – Returns an empty array.

_access_denied_splash() – Displays an access denied message when a user tries to view a site’s dashboard they do not have access to.

_add_post_type_submenus() – Add submenus for post types.

_add_themes_utility_last() – Adds the (theme) ‘Editor’ link to the bottom of the Appearance menu.

_admin_bar_bump_cb() – Default admin bar callback.

_admin_notice_post_locked() – Outputs the HTML for the notice to say that someone else is editing or has taken over editing of this post.

_admin_search_query() – Displays the search query.

_ajax_wp_die_handler() – Kill WordPress ajax execution.

_autop_newline_preservation_helper() – Newline preservation help function for wpautop

_cleanup_image_add_caption() – Private preg_replace callback used in image_add_caption()

_delete_attachment_theme_mod() – Checks an attachment being deleted to see if it’s a header or background image.

_deprecated_argument() – Mark a function argument as deprecated and inform when it has been used.

_filter_query_attachment_filenames() – Filter the SQL clauses of an attachment query to include filenames.

_fix_attachment_links() – Replace hrefs of attachment anchors with up-to-date permalinks.

_get_additional_user_keys() – Returns a list of meta keys to be (maybe) populated in wp_update_user().

_get_admin_bar_pref() – Retrieve the admin bar display preference of a user.

_get_cron_array() – Retrieve cron info array option.

_get_post_ancestors() – Retrieve post ancestors.

_links_add_base() – Callback to add a base url to relative links in passed content.

_links_add_target() – Callback to add a target attribute to all links in passed content.

_redirect_to_about_wordpress() – Redirect to the About WordPress page after a successful upgrade.

_remove_qs_args_if_not_in_url() – Removes arguments from a query string if they are not present in a URL DO NOT use this in plugin code.

_set_cron_array() – Updates the CRON option with the new CRON array.

_thickbox_path_admin_subfolder() – Thickbox image paths for Network Admin.

_upgrade_cron_array() – Upgrade a Cron info array.

_wp_add_global_attributes() – Helper function to add global attributes to a tag in the allowed html list.

_wp_admin_bar_init() – Instantiate the admin bar object and set it up as a global for access elsewhere.

_wp_admin_html_begin() –

_wp_ajax_add_hierarchical_term() – Ajax handler for adding a hierarchical term.

_wp_ajax_delete_comment_response() – Sends back current comment total and new page links if they need to be updated.

_wp_ajax_menu_quick_search() – Prints the appropriate response to a menu quick search.

_wp_auto_add_pages_to_menu() – Automatically add newly published page objects to menus with that as an option.

_wp_call_all_hook() – Call the ‘all’ hook, which will process the functions hooked into it.

_wp_credits_add_profile_link() – Retrieve the link to a contributor’s WordPress.org profile page.

_WP_Dependency::add_data() – Add handle data.

_wp_get_allowed_postdata() – Returns only allowed post data fields

_wp_get_attachment_relative_path() – Get the attachment path relative to the upload directory.

_wp_keep_alive_customize_changeset_dependent_auto_drafts() – Make sure that auto-draft posts get their post_date bumped or status changed to draft to prevent premature garbage-collection.

_wp_privacy_account_request_confirmed_message() – Return request confirmation message HTML.

_wp_privacy_account_request_confirmed() – Update log when privacy request is confirmed.

_wp_privacy_action_request_types() – Get all user privacy request types.

_wp_register_meta_args_whitelist() – Filter out `register_meta()` args based on a whitelist.

_wpseo_activate() – Runs on activation of the plugin.

_yoast_display_alerts() – Create the alert HTML with restore/dismiss button.

absint() – Convert a value to non-negative integer.

AbstractLogger::alert() – Action must be taken immediately.

AbstractLogger::critical() – Critical conditions.

AbstractLogger::debug() – Detailed debug information.

AbstractLogger::emergency() – System is unusable.

AbstractLogger::error() – Runtime errors that do not require immediate action but should typically be logged and monitored.

AbstractLogger::info() – Interesting events.

AbstractLogger::notice() – Normal but significant events.

AbstractLogger::warning() – Exceptional occurrences that are not errors.

Actions::compile_dependency_injection_container() – Compiles the dependency injection container.

Actions::prefix_dependencies() – Prefixes dependencies if composer install is ran with dev mode.

activate_plugin() – Attempts activation of plugin in a "sandbox" and redirects on success.

activate_plugins() – Activate multiple plugins.

activate_sitewide_plugin() – Deprecated functionality for activating a network-only plugin.

add_action() – Hooks a function on to a specific action.

add_blog_option() – Add a new option for a given blog id.

add_clean_index() – Adds an index to a specified table.

add_column() – add column

add_comment_meta() – Add meta data field to a comment.

add_comments_page() – Add submenu page to the Comments main menu.

add_contextual_help() – Add contextual help text for a page.

add_cssclass() –

add_custom_background() – Add callbacks for background image display.

add_custom_image_header() – Add callbacks for image header display.

add_dashboard_page() – Add submenu page to the Dashboard main menu.

add_editor_style() – Add callback for custom TinyMCE editor stylesheets.

add_existing_user_to_blog() – Add a user to a blog based on details from maybe_add_existing_user_to_blog().

add_feed() – Add a new feed type like /atom1/.

add_filter() – Hook a function or method to a specific filter action.

add_image_size() – Register a new image size.

add_index() – add index

add_link() – Add a link to using values provided in $_POST.

add_links_page() – Add submenu page to the Links main menu.

add_magic_quotes() – Walks the array while sanitizing the contents.

add_management_page() – Add submenu page to the Tools main menu.

add_media_page() – Add submenu page to the Media main menu.

add_menu_classes() –

add_menu_page() – Add a top-level menu page.

add_meta_box() – Adds a meta box to one or more screens.

add_meta() – Add post meta data defined in $_POST superglobal for post with given ID.

add_metadata() – Add metadata for the specified object.

add_network_option() – Add a new network option.

add_new_user_to_blog() – Adds a newly created user to the appropriate blog

add_object_page() – Add a top-level menu page in the ‘objects’ section.

add_option_update_handler() – Register a setting and its sanitization callback

add_option_whitelist() – Adds an array of options to the options whitelist.

add_option() – Add a new option.

add_options_page() – Add submenu page to the Settings main menu.

add_pages_page() – Add submenu page to the Pages main menu.

add_permastruct() – Add permalink structure.

add_ping() – Add a URL to those already pinged.

add_plugins_page() – Add submenu page to the Plugins main menu.

add_post_meta() – Add meta data field to a post.

add_post_type_support() – Register support of certain features for a post type.

add_posts_page() – Add submenu page to the Posts main menu.

add_query_arg() – Retrieves a modified URL query string.