_

__() – 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() –

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

__get() –

__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() – Kills WordPress execution and displays Ajax response with an error message.

_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 displays HTML page with an 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.

_disable_reqs() –

_doing_it_wrong() – Mark something as being incorrectly called.

_draft_or_post_title() – Get the post title.

_e() – Display translated text.

_edd_anonymize_customer() – Given a customer ID, anonymize the data related to that customer.

_edd_anonymize_payment() – Given a payment ID, anonymize the data related to that payment.

_edd_deprecated_function() – Marks a function as deprecated and informs when it has been used.

_edd_deprected_argument() – Marks an argument in a function deprecated and informs when it’s been used

_edd_die_handler() – Register die handler for edd_die()

_edd_privacy_get_customer_id_for_email() – Since our eraser callbacks need to look up a stored customer ID by hashed email address, developers can use this to retrieve the customer ID associated with an email address that’s being requested to be deleted even after the customer has been anonymized.

_edd_privacy_get_payment_action() – Given an EDD_Payment, determine what action should be taken during the eraser processes.

_ex() – Display translated string with gettext context.

_excerpt_render_inner_columns_blocks() – Render inner blocks from the `core/columns` block for generating an excerpt.

_excerpt_render_inner_columns_blocks() – Render inner blocks from the `core/columns` block for generating an excerpt.

_excerpt_render_inner_columns_blocks() – Render inner blocks from the `core/columns` block for generating an excerpt.

_excerpt_render_inner_columns_blocks() – Render inner blocks from the `core/columns` block for generating an excerpt.

_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.