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wp-includes/functions.php › WordPress File

Main WordPress API

Function Short description
absintConvert a value to non-negative integer.
add_magic_quotesWalks the array while sanitizing the contents.
add_query_argRetrieves a modified URL query string.
apache_mod_loadedDoes the specified module exist in the Apache config?
bool_from_ynWhether input is yes or no.
build_queryBuild URL query based on an associative and, or indexed array.
cache_javascript_headersSet the headers for caching for 10 days with JavaScript content type.
clean_dirsize_cacheCleans directory size cache used by recurse_dirsize().
current_datetimeRetrieves the current time as an object using the site's timezone.
current_timeRetrieves the current time based on specified type.
date_i18nRetrieves the date in localized format, based on a sum of Unix timestamp and timezone offset in seconds.
dead_dbLoad custom DB error or display WordPress DB error.
do_encloseCheck content for video and audio links to add as enclosures.
do_faviconDisplay the favicon.ico file content.
do_feedLoad the feed template from the use of an action hook.
do_feed_atomLoad either Atom comment feed or Atom posts feed.
do_feed_rdfLoad the RDF RSS 0.91 Feed template.
do_feed_rssLoad the RSS 1.0 Feed Template.
do_feed_rss2Load either the RSS2 comment feed or the RSS2 posts feed.
do_robotsDisplays the default robots.txt file content.
force_ssl_adminWhether to force SSL used for the Administration Screens.
get_allowed_mime_typesRetrieve list of allowed mime types and file extensions.
get_dirsizeGet the size of a directory.
get_file_dataRetrieve metadata from a file.
get_main_network_idGet the main network ID.
get_main_site_idGets the main site ID.
get_num_queriesRetrieve the number of database queries during the WordPress execution.
get_status_header_descRetrieve the description for the HTTP status.
get_tag_regexReturn RegEx body to liberally match an opening HTML tag.
get_temp_dirDetermine a writable directory for temporary files.
get_weekstartendGet the week start and end from the datetime or date string from MySQL.
global_terms_enabledDetermine whether global terms are enabled.
human_readable_durationConvert a duration to human readable format.
iis7_supports_permalinksCheck if IIS 7+ supports pretty permalinks.
is_blog_installedDetermines whether WordPress is already installed.
is_lighttpd_before_150Is the server running earlier than 1.5.0 version of lighttpd?
is_main_networkDetermine whether a network is the main network of the Multisite installation.
is_main_siteDetermine whether a site is the main site of the current network.
is_new_dayDetermines whether the publish date of the current post in the loop is different from the publish date of the previous post in the loop.
is_php_version_compatibleChecks compatibility with the current PHP version.
is_serializedCheck value to find if it was serialized.
is_serialized_stringCheck whether serialized data is of string type.
is_site_meta_supportedDetermines whether site meta is enabled.
is_wp_version_compatibleChecks compatibility with the current WordPress version.
maybe_serializeSerialize data, if needed.
maybe_unserializeUnserialize data only if it was serialized.
mbstring_binary_safe_encodingSet the mbstring internal encoding to a binary safe encoding when func_overload is enabled.
mysql2dateConvert given MySQL date string into a different format.
mysql_to_rfc3339Parses and formats a MySQL datetime (Y-m-d H:i:s) for ISO8601 (Y-m-d\TH:i:s).
nocache_headersSet the headers to prevent caching for the different browsers.
number_format_i18nConvert float number to format based on the locale.
path_is_absoluteTest if a given filesystem path is absolute.
path_joinJoin two filesystem paths together.
recurse_dirsizeGet the size of a directory recursively.
remove_query_argRemoves an item or items from a query string.
reset_mbstring_encodingReset the mbstring internal encoding to a users previously set encoding.
send_frame_options_headerSend a HTTP header to limit rendering of pages to same origin iframes.
send_nosniff_headerSend a HTTP header to disable content type sniffing in browsers which support it.
size_formatConvert number of bytes largest unit bytes will fit into.
smilies_initConvert smiley code to the icon graphic file equivalent.
status_headerSet HTTP status header.
validate_fileValidates a file name and path against an allowed set of rules.
win_is_writableWorkaround for Windows bug in is_writable() function
wpSet up the WordPress query.
wp_allowed_protocolsRetrieve a list of protocols to allow in HTML attributes.
wp_array_slice_assocExtract a slice of an array, given a list of keys.
wp_auth_checkCheck whether a user is still logged in, for the heartbeat.
wp_auth_check_htmlOutput the HTML that shows the wp-login dialog when the user is no longer logged in.
wp_auth_check_loadLoad the auth check for monitoring whether the user is still logged in.
wp_cache_get_last_changedGets last changed date for the specified cache group.
wp_checkdateTest if the supplied date is valid for the Gregorian calendar.
wp_check_filetypeRetrieve the file type from the file name.
wp_check_filetype_and_extAttempt to determine the real file type of a file.
wp_check_jsonp_callbackChecks that a JSONP callback is a valid JavaScript callback name.
wp_dateRetrieves the date, in localized format.
wp_debug_backtrace_summaryReturn a comma-separated string of functions that have been called to get to the current point in code.
wp_delete_fileDelete a file
wp_delete_file_from_directoryDeletes a file if its path is within the given directory.
wp_dieKills WordPress execution and displays HTML page with an error message.
wp_direct_php_update_buttonDisplay a button directly linking to a PHP update process.
wp_ext2typeRetrieve the file type based on the extension name.
wp_extract_urlsUse RegEx to extract URLs from arbitrary content.
wp_filter_object_listFilters a list of objects, based on a set of key => value arguments.
wp_find_hierarchy_loopFind hierarchy loops using a callback function that maps object IDs to parent IDs.
wp_find_hierarchy_loop_tortoise_hareUse the "The Tortoise and the Hare" algorithm to detect loops.
wp_fuzzy_number_matchCheck if two numbers are nearly the same.
wp_generate_uuid4Generate a random UUID (version 4).
wp_get_default_extension_for_mime_typeReturns first matched extension for the mime-type, as mapped from wp_get_mime_types().
wp_get_default_update_https_urlGets the default URL to learn more about updating the site to use HTTPS.
wp_get_default_update_php_urlGets the default URL to learn more about updating the PHP version the site is running on.
wp_get_direct_php_update_urlGets the URL for directly updating the PHP version the site is running on.
wp_get_direct_update_https_urlGets the URL for directly updating the site to use HTTPS.
wp_get_ext_typesRetrieves the list of common file extensions and their types.
wp_get_http_headersRetrieve HTTP Headers from URL.
wp_get_image_mimeReturns the real mime type of an image file.
wp_get_mime_typesRetrieve list of mime types and file extensions.
wp_get_nocache_headersGet the header information to prevent caching.
wp_get_original_refererRetrieve original referer that was posted, if it exists.
wp_get_raw_refererRetrieves unvalidated referer from '_wp_http_referer' or HTTP referer.
wp_get_refererRetrieve referer from '_wp_http_referer' or HTTP referer.
wp_get_update_https_urlGets the URL to learn more about updating the site to use HTTPS.
wp_get_update_php_annotationReturns the default annotation for the web hosting altering the "Update PHP" page URL.
wp_get_update_php_urlGets the URL to learn more about updating the PHP version the site is running on.
wp_get_upload_dirRetrieves uploads directory information.
wp_guess_urlGuess the URL for the site.
wp_is_numeric_arrayDetermines if the variable is a numeric-indexed array.
wp_is_streamTest if a given path is a stream URL
wp_is_uuidValidates that a UUID is valid.
wp_is_writableDetermine if a directory is writable.
wp_json_encodeEncode a variable into JSON, with some sanity checks.
wp_json_file_decodeReads and decodes a JSON file.
wp_list_filterFilters a list of objects, based on a set of key => value arguments.
wp_list_pluckPluck a certain field out of each object in a list.
wp_list_sortSorts a list of objects, based on one or more orderby arguments.
wp_maybe_decline_dateDetermines if the date should be declined.
wp_maybe_load_widgetsDetermines if Widgets library should be loaded.
wp_mkdir_pRecursive directory creation based on full path.
wp_nonce_aysDisplay "Are You Sure" message to confirm the action being taken.
wp_nonce_fieldRetrieve or display nonce hidden field for forms.
wp_nonce_urlRetrieve URL with nonce added to URL query.
wp_normalize_pathNormalize a filesystem path.
wp_ob_end_flush_allFlush all output buffers for PHP 5.2.
wp_original_referer_fieldRetrieve or display original referer hidden field for forms.
wp_parse_argsMerges user defined arguments into defaults array.
wp_parse_id_listCleans up an array, comma- or space-separated list of IDs.
wp_parse_listConverts a comma- or space-separated list of scalar values to an array.
wp_parse_slug_listCleans up an array, comma- or space-separated list of slugs.
wp_post_preview_jsOutputs a small JS snippet on preview tabs/windows to remove `window.name` on unload.
wp_privacy_anonymize_dataReturn uniform "anonymous" data by type.
wp_privacy_anonymize_ipReturn an anonymized IPv4 or IPv6 address.
wp_privacy_delete_old_export_filesCleans up export files older than three days old.
wp_privacy_exports_dirReturns the directory used to store personal data export files.
wp_privacy_exports_urlReturns the URL of the directory used to store personal data export files.
wp_raise_memory_limitAttempts to raise the PHP memory limit for memory intensive processes.
wp_referer_fieldRetrieve or display referer hidden field for forms.
wp_remote_fopenHTTP request for URI to retrieve content.
wp_removable_query_argsReturns an array of single-use query variable names that can be removed from a URL.
wp_scheduled_deletePermanently delete comments or posts of any type that have held a status of 'trash' for the number of days defined in EMPTY_TRASH_DAYS.
wp_schedule_delete_old_privacy_export_filesSchedule a `WP_Cron` job to delete expired export files.
wp_send_jsonSend a JSON response back to an Ajax request.
wp_send_json_errorSend a JSON response back to an Ajax request, indicating failure.
wp_send_json_successSend a JSON response back to an Ajax request, indicating success.
wp_site_admin_email_change_notificationSend an email to the old site admin email address when the site admin email address changes.
wp_suspend_cache_additionTemporarily suspend cache additions.
wp_suspend_cache_invalidationSuspend cache invalidation.
wp_timezoneRetrieves the timezone of the site as a `DateTimeZone` object.
wp_timezone_choiceGives a nicely-formatted list of timezone strings.
wp_timezone_override_offsetgmt_offset modification for smart timezone handling.
wp_timezone_stringRetrieves the timezone of the site as a string.
wp_unique_filenameGet a filename that is sanitized and unique for the given directory.
wp_unique_idGets unique ID.
wp_update_php_annotationPrints the default annotation for the web host altering the "Update PHP" page URL.
wp_upload_bitsCreate a file in the upload folder with given content.
wp_upload_dirReturns an array containing the current upload directory's path and URL.
wp_validate_booleanFilter/validate a variable as a boolean.
wp_widgets_add_menuAppend the Widgets menu to the themes main menu.
xmlrpc_getpostcategoryRetrieve the post category or categories from XMLRPC XML.
xmlrpc_getposttitleRetrieve post title from XMLRPC XML.
xmlrpc_removepostdataXMLRPC XML content without title and category elements.
_ajax_wp_die_handlerKills WordPress execution and displays Ajax response with an error message.
_canonical_charsetRetrieve a canonical form of the provided charset appropriate for passing to PHP functions such as htmlspecialchars() and charset HTML attributes.
_cleanup_header_commentStrip close comment and close php tags from file headers used by WP.
_config_wp_homeRetrieve the WordPress home page URL.
_config_wp_siteurlRetrieve the WordPress site URL.
_default_wp_die_handlerKills WordPress execution and displays HTML page with an error message.
_delete_option_fresh_siteDelete the fresh site option.
_deprecated_argumentMark a function argument as deprecated and inform when it has been used.
_deprecated_constructorMarks a constructor as deprecated and informs when it has been used.
_deprecated_fileMark a file as deprecated and inform when it has been used.
_deprecated_functionMark a function as deprecated and inform when it has been used.
_deprecated_hookMarks a deprecated action or filter hook as deprecated and throws a notice.
_device_can_uploadTest if the current device has the capability to upload files.
_doing_it_wrongMark something as being incorrectly called.
_get_non_cached_idsRetrieve IDs that are not already present in the cache.
_http_build_queryFrom php.net (modified by Mark Jaquith to behave like the native PHP5 function).
_jsonp_wp_die_handlerKills WordPress execution and displays JSONP response with an error message.
_json_wp_die_handlerKills WordPress execution and displays JSON response with an error message.
_mce_set_directionSet the localized direction for MCE plugin.
_scalar_wp_die_handlerKills WordPress execution and displays an error message.
_wp_array_getAccesses an array in depth based on a path of keys.
_wp_array_setSets an array in depth based on a path of keys.
_wp_check_alternate_file_namesHelper function to test if each of an array of file names could conflict with existing files.
_wp_check_existing_file_namesHelper function to check if a file name could match an existing image sub-size file name.
_wp_die_process_inputProcesses arguments passed to wp_die() consistently for its handlers.
_wp_timezone_choice_usort_callbackSort-helper for timezones.
_wp_to_kebab_caseThis function is trying to replicate what lodash's kebabCase (JS library) does in the client.
_wp_upload_dirA non-filtered, non-cached version of wp_upload_dir() that doesn't check the path.
_xmlrpc_wp_die_handlerKills WordPress execution and displays XML response with an error message.
_xml_wp_die_handlerKills WordPress execution and displays XML response with an error message.
__return_empty_arrayReturns an empty array.
__return_empty_stringReturns an empty string.
__return_falseReturns false.
__return_nullReturns null.
__return_trueReturns true.
__return_zeroReturns 0.