_

__() – Retrieve the translation of $text.

__autoload() – Autoloader compatibility callback.

__checked_selected_helper() – Private helper function for checked, selected, disabled and readonly.

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

__construct() – Create a new cache object

__get_option() – Utility version of get_option that is private to installation/upgrade.

__ngettext_noop() – Register plural strings in POT file, but don’t translate them.

__ngettext() – Retrieve the plural or single form based on the amount.

__return_empty_array() – Returns an empty array.

__return_empty_string() – Returns an empty string.

__return_false() – Returns false.

__return_null() – Returns null.

__return_true() – Returns true.

__return_zero() – Returns 0.

_() – WordPress implementation for PHP functions either missing from older PHP versions or not included by default.

_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

_c() – Retrieve translated string with vertical bar context

_canonical_charset() – Retrieve a canonical form of the provided charset appropriate for passing to PHP functions such as htmlspecialchars() and charset html attributes.

_cleanup_header_comment() – Strip close comment and close php tags from file headers used by WP.

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

_clear_modified_cache_on_transition_comment_status() – Clear the lastcommentmodified cached value when a comment status is changed.

_close_comments_for_old_post() – Close comments on an old post. Hooked to comments_open and pings_open.

_close_comments_for_old_posts() – Close comments on old posts on the fly, without any extra DB queries. Hooked to the_posts.

_config_wp_home() – Retrieve the WordPress home page URL.

_config_wp_siteurl() – Retrieve the WordPress site URL.

_convert_urlencoded_to_entities() – Preview fix for JavaScript bug with foreign languages.

_copy_dir() – Copies a directory from one location to another via the WordPress Filesystem Abstraction.

_copy_image_file() – Copy an existing image file.

_count_posts_cache_key() – Return the cache key for wp_count_posts() based on the passed arguments.

_crop_image_resource() – Crops an image resource. Internal use only.

_custom_background_cb() – Default custom background callback.

_custom_header_background_just_in_time() – Registers the internal custom header and background routines.

_custom_logo_header_styles() – Adds CSS to hide header text for custom logo, based on Customizer setting.

_deep_replace() – Perform a deep string replace operation to ensure the values in $search are no longer present

_default_wp_die_handler() – Kills WordPress execution and display HTML message with error message.

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

_delete_option_fresh_site() – Delete the fresh site option.

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

_deprecated_constructor() – Marks a constructor as deprecated and informs when it has been used.

_deprecated_file() – Mark a file as deprecated and inform when it has been used.

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

_deprecated_hook() – Marks a deprecated action or filter hook as deprecated and throws a notice.

_device_can_upload() – Test if the current device has the capability to upload files.

_doing_it_wrong() – Mark something as being incorrectly called.

_draft_or_post_title() – Get the post title.

_e() – Display translated text.

_ex() – Display translated string with gettext context.

_fetch_remote_file() – Retrieve URL headers and content using WP HTTP Request API.

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

_find_post_by_old_date() – Find the post ID for redirecting an old date.

_find_post_by_old_slug() – Find the post ID for redirecting an old slug.

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

_flip_image_resource() – Flips an image resource. Internal use only.

_future_post_hook() – Hook used to schedule publication for a post marked for the future.

_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_component_from_parsed_url_array() – Retrieve a specific component from a parsed URL array.

_get_cron_array() – Retrieve cron info array option.

_get_cron_lock() – Retrieves the cron lock.

_get_custom_object_labels() – Build an object with custom-something object (post type, taxonomy) labels out of a custom-something object

_get_dropins() – Returns drop-ins that WordPress uses.

_get_last_post_time() – Get the timestamp of the last time any post was modified or published.

_get_list_table() – Fetches an instance of a WP_List_Table class.

_get_meta_table() – Retrieve the name of the metadata table for the specified object type.

_get_non_cached_ids() – Retrieve IDs that are not already present in the cache.

_get_page_link() – Retrieves the page permalink.

_get_path_to_translation_from_lang_dir() – Gets the path to a translation file in the languages directory for the current locale.

_get_path_to_translation() – Gets the path to a translation file for loading a textdomain just in time.

_get_plugin_data_markup_translate() – Sanitizes plugin data, optionally adds markup, optionally translates.

_get_plugin_from_callback() – Internal helper function to find the plugin from a meta box callback.

_get_post_ancestors() – Retrieve post ancestors.

_get_random_header_data() – Get random header image data from registered images in theme.

_get_template_edit_filename() – Tidies a filename for url display by the theme editor.

_get_term_children() – Get the subset of $terms that are descendants of $term_id.

_get_term_hierarchy() – Retrieves children of taxonomy as Term IDs.

_get_widget_id_base() – Retrieves the widget ID base value.

_get_wptexturize_shortcode_regex() – Retrieve the regular expression for shortcodes.

_get_wptexturize_split_regex() – Retrieve the combined regular expression for HTML and shortcodes.

_hash_hmac() – Internal compat function to mimic hash_hmac().

_http_build_query() – From php.net (modified by Mark Jaquith to behave like the native PHP5 function).

_image_get_preview_ratio() – Image preview ratio. Internal use only.

_insert_into_post_button() – This was once used to display an ‘Insert into Post’ button.

_ipad_meta() –

_is_valid_nav_menu_item() – Return if a menu item is valid.

_json_decode_object_helper() –

_json_wp_die_handler() – Kill WordPress execution and display JSON message with error message.

_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.

_list_meta_row() – Outputs a single row of public meta data in the Custom Fields meta box.

_load_image_to_edit_path() – Retrieve the path or url of an attachment’s attached file.

_load_textdomain_just_in_time() – Loads plugin and theme textdomains just-in-time.

_local_storage_notice() – Output the HTML for restoring the post data from DOM storage

_make_cat_compat() – Update category structure to old pre 2.3 from new taxonomy structure.

_make_email_clickable_cb() – Callback to convert email address match to HTML A element.

_make_url_clickable_cb() – Callback to convert URI match to HTML A element.