Title: Multisite | Page 8 of 11 | Developer.WordPress.org --- # @package: Multisite * function[update_posts_count()](https://developer.wordpress.org/reference/functions/update_posts_count/) * Updates a blog’s post count. * Used by [3 functions](https://developer.wordpress.org/reference/functions/update_posts_count/#used-by) | Uses [2 functions](https://developer.wordpress.org/reference/functions/update_posts_count/#uses) | Source: [wp-includes/ms-functions.php:2074](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L2074-L2077) * function[wpmu_log_new_registrations()](https://developer.wordpress.org/reference/functions/wpmu_log_new_registrations/) * Logs the user email, IP, and registration date of a new site. * Used by [0 functions](https://developer.wordpress.org/reference/functions/wpmu_log_new_registrations/#used-by) | Uses [4 functions](https://developer.wordpress.org/reference/functions/wpmu_log_new_registrations/#uses) | Source: [wp-includes/ms-functions.php:2090](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L2090-L2113) * function[redirect_this_site()](https://developer.wordpress.org/reference/functions/redirect_this_site/) * Ensures that the current site’s domain is listed in the allowed redirect host list. * Used by [0 functions](https://developer.wordpress.org/reference/functions/redirect_this_site/#used-by) | Uses [1 function](https://developer.wordpress.org/reference/functions/redirect_this_site/#uses) | Source: [wp-includes/ms-functions.php:2128](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L2128-L2130) * function[upload_is_file_too_big()](https://developer.wordpress.org/reference/functions/upload_is_file_too_big/) * Checks whether an upload is too big. * Used by [0 functions](https://developer.wordpress.org/reference/functions/upload_is_file_too_big/#used-by) | Uses [2 functions](https://developer.wordpress.org/reference/functions/upload_is_file_too_big/#uses) | Source: [wp-includes/ms-functions.php:2140](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L2140-L2151) * hook[domain_exists](https://developer.wordpress.org/reference/hooks/domain_exists/) * Filters whether a site name is taken. * Used by [1 function](https://developer.wordpress.org/reference/hooks/domain_exists/#used-by) | Uses [0 functions](https://developer.wordpress.org/reference/hooks/domain_exists/#uses) | Source: [wp-includes/ms-functions.php:1617](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1617-L1617) * function[wpmu_welcome_notification()](https://developer.wordpress.org/reference/functions/wpmu_welcome_notification/) * Notifies the site administrator that their site activation was successful. * Used by [0 functions](https://developer.wordpress.org/reference/functions/wpmu_welcome_notification/#used-by) | Uses [15 functions](https://developer.wordpress.org/reference/functions/wpmu_welcome_notification/#uses) | Source: [wp-includes/ms-functions.php:1637](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1637-L1747) * hook[wpmu_welcome_notification](https://developer.wordpress.org/reference/hooks/wpmu_welcome_notification/) * Filters whether to bypass the welcome email sent to the site administrator after site activation. * Used by [1 function](https://developer.wordpress.org/reference/hooks/wpmu_welcome_notification/#used-by) | Uses [0 functions](https://developer.wordpress.org/reference/hooks/wpmu_welcome_notification/#uses) | Source: [wp-includes/ms-functions.php:1660](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1660-L1660) * function[wpmu_activate_signup()](https://developer.wordpress.org/reference/functions/wpmu_activate_signup/) * Activates a signup. * Used by [0 functions](https://developer.wordpress.org/reference/functions/wpmu_activate_signup/#used-by) | Uses [14 functions](https://developer.wordpress.org/reference/functions/wpmu_activate_signup/#uses) | Source: [wp-includes/ms-functions.php:1193](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1193-L1314) * hook[wpmu_activate_user](https://developer.wordpress.org/reference/hooks/wpmu_activate_user/) * Fires immediately after a new user is activated. * Used by [1 function](https://developer.wordpress.org/reference/hooks/wpmu_activate_user/#used-by) | Uses [0 functions](https://developer.wordpress.org/reference/hooks/wpmu_activate_user/#uses) | Source: [wp-includes/ms-functions.php:1253](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1253-L1253) * hook[wpmu_activate_blog](https://developer.wordpress.org/reference/hooks/wpmu_activate_blog/) * Fires immediately after a site is activated. * Used by [1 function](https://developer.wordpress.org/reference/hooks/wpmu_activate_blog/#used-by) | Uses [0 functions](https://developer.wordpress.org/reference/hooks/wpmu_activate_blog/#uses) | Source: [wp-includes/ms-functions.php:1305](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1305-L1305) * function[wpmu_create_user()](https://developer.wordpress.org/reference/functions/wpmu_create_user/) * Creates a user. * Used by [2 functions](https://developer.wordpress.org/reference/functions/wpmu_create_user/#used-by) | Uses [5 functions](https://developer.wordpress.org/reference/functions/wpmu_create_user/#uses) | Source: [wp-includes/ms-functions.php:1348](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1348-L1375) * hook[wpmu_new_user](https://developer.wordpress.org/reference/hooks/wpmu_new_user/) * Fires immediately after a new user is created. * Used by [1 function](https://developer.wordpress.org/reference/hooks/wpmu_new_user/#used-by) | Uses [0 functions](https://developer.wordpress.org/reference/hooks/wpmu_new_user/#uses) | Source: [wp-includes/ms-functions.php:1372](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1372-L1372) * function[wpmu_create_blog()](https://developer.wordpress.org/reference/functions/wpmu_create_blog/) * Creates a site. * Used by [2 functions](https://developer.wordpress.org/reference/functions/wpmu_create_blog/#used-by) | Uses [8 functions](https://developer.wordpress.org/reference/functions/wpmu_create_blog/#uses) | Source: [wp-includes/ms-functions.php:1404](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1404-L1449) * hook[wpmu_new_blog](https://developer.wordpress.org/reference/hooks/wpmu_new_blog/) * Fires immediately after a new site is created. * Used by [1 function](https://developer.wordpress.org/reference/hooks/wpmu_new_blog/#used-by) | Uses [0 functions](https://developer.wordpress.org/reference/hooks/wpmu_new_blog/#uses) | Source: [wp-includes/ms-site.php:137](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-site.php#L137-L142) * function[newblog_notify_siteadmin()](https://developer.wordpress.org/reference/functions/newblog_notify_siteadmin/) * Notifies the network admin that a new site has been activated. * Used by [0 functions](https://developer.wordpress.org/reference/functions/newblog_notify_siteadmin/#used-by) | Uses [12 functions](https://developer.wordpress.org/reference/functions/newblog_notify_siteadmin/#uses) | Source: [wp-includes/ms-functions.php:1464](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1464-L1516) * hook[newblog_notify_siteadmin](https://developer.wordpress.org/reference/hooks/newblog_notify_siteadmin/) * Filters the message body of the new site activation email sent to the network administrator. * Used by [1 function](https://developer.wordpress.org/reference/hooks/newblog_notify_siteadmin/#used-by) | Uses [0 functions](https://developer.wordpress.org/reference/hooks/newblog_notify_siteadmin/#uses) | Source: [wp-includes/ms-functions.php:1510](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1510-L1510) * function[newuser_notify_siteadmin()](https://developer.wordpress.org/reference/functions/newuser_notify_siteadmin/) * Notifies the network admin that a new user has been activated. * Used by [0 functions](https://developer.wordpress.org/reference/functions/newuser_notify_siteadmin/#used-by) | Uses [9 functions](https://developer.wordpress.org/reference/functions/newuser_notify_siteadmin/#uses) | Source: [wp-includes/ms-functions.php:1529](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1529-L1572) * hook[newuser_notify_siteadmin](https://developer.wordpress.org/reference/hooks/newuser_notify_siteadmin/) * Filters the message body of the new user activation email sent to the network administrator. * Used by [1 function](https://developer.wordpress.org/reference/hooks/newuser_notify_siteadmin/#used-by) | Uses [0 functions](https://developer.wordpress.org/reference/hooks/newuser_notify_siteadmin/#uses) | Source: [wp-includes/ms-functions.php:1566](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1566-L1566) * function[domain_exists()](https://developer.wordpress.org/reference/functions/domain_exists/) * Checks whether a site name is already taken. * Used by [4 functions](https://developer.wordpress.org/reference/functions/domain_exists/#used-by) | Uses [3 functions](https://developer.wordpress.org/reference/functions/domain_exists/#uses) | Source: [wp-includes/ms-functions.php:1591](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1591-L1618) * function[wpmu_signup_user_notification()](https://developer.wordpress.org/reference/functions/wpmu_signup_user_notification/) * Sends a confirmation request email to a user when they sign up for a new user account (without signing up for a site at the same time). The user account will not become active until the confirmation link is clicked. * Used by [0 functions](https://developer.wordpress.org/reference/functions/wpmu_signup_user_notification/#used-by) | Uses [14 functions](https://developer.wordpress.org/reference/functions/wpmu_signup_user_notification/#uses) | Source: [wp-includes/ms-functions.php:1085](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1085-L1176) * hook[wpmu_signup_user_notification](https://developer.wordpress.org/reference/hooks/wpmu_signup_user_notification/) * Filters whether to bypass the email notification for new user sign-up. * Used by [1 function](https://developer.wordpress.org/reference/hooks/wpmu_signup_user_notification/#used-by) | Uses [0 functions](https://developer.wordpress.org/reference/hooks/wpmu_signup_user_notification/#uses) | Source: [wp-includes/ms-functions.php:1102](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1102-L1102) * function[is_email_address_unsafe()](https://developer.wordpress.org/reference/functions/is_email_address_unsafe/) * Checks an email address against a list of banned domains. * Used by [1 function](https://developer.wordpress.org/reference/functions/is_email_address_unsafe/#used-by) | Uses [2 functions](https://developer.wordpress.org/reference/functions/is_email_address_unsafe/#uses) | Source: [wp-includes/ms-functions.php:398](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L398-L438) * hook[wpmu_signup_user_notification_email](https://developer.wordpress.org/reference/hooks/wpmu_signup_user_notification_email/) * Filters the content of the notification email for new user sign-up. * Used by [1 function](https://developer.wordpress.org/reference/hooks/wpmu_signup_user_notification_email/#used-by) | Uses [0 functions](https://developer.wordpress.org/reference/hooks/wpmu_signup_user_notification_email/#uses) | Source: [wp-includes/ms-functions.php:1132](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1132-L1140) * hook[is_email_address_unsafe](https://developer.wordpress.org/reference/hooks/is_email_address_unsafe/) * Filters whether an email address is unsafe. * Used by [1 function](https://developer.wordpress.org/reference/hooks/is_email_address_unsafe/#used-by) | Uses [0 functions](https://developer.wordpress.org/reference/hooks/is_email_address_unsafe/#uses) | Source: [wp-includes/ms-functions.php:437](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L437-L437) * hook[wpmu_signup_user_notification_subject](https://developer.wordpress.org/reference/hooks/wpmu_signup_user_notification_subject/) * Filters the subject of the notification email of new user signup. * Used by [1 function](https://developer.wordpress.org/reference/hooks/wpmu_signup_user_notification_subject/#used-by) | Uses [0 functions](https://developer.wordpress.org/reference/hooks/wpmu_signup_user_notification_subject/#uses) | Source: [wp-includes/ms-functions.php:1156](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L1156-L1164) * function[wpmu_validate_user_signup()](https://developer.wordpress.org/reference/functions/wpmu_validate_user_signup/) * Sanitizes and validates data required for a user sign-up. * Used by [3 functions](https://developer.wordpress.org/reference/functions/wpmu_validate_user_signup/#used-by) | Uses [16 functions](https://developer.wordpress.org/reference/functions/wpmu_validate_user_signup/#uses) | Source: [wp-includes/ms-functions.php:468](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L468-L602) * hook[wpmu_validate_user_signup](https://developer.wordpress.org/reference/hooks/wpmu_validate_user_signup/) * Filters the validated user registration details. * Used by [1 function](https://developer.wordpress.org/reference/hooks/wpmu_validate_user_signup/#used-by) | Uses [0 functions](https://developer.wordpress.org/reference/hooks/wpmu_validate_user_signup/#uses) | Source: [wp-includes/ms-functions.php:601](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L601-L601) * function[wpmu_validate_blog_signup()](https://developer.wordpress.org/reference/functions/wpmu_validate_blog_signup/) * Processes new site registrations. * Used by [2 functions](https://developer.wordpress.org/reference/functions/wpmu_validate_blog_signup/#used-by) | Uses [19 functions](https://developer.wordpress.org/reference/functions/wpmu_validate_blog_signup/#uses) | Source: [wp-includes/ms-functions.php:638](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L638-L785) * hook[subdirectory_reserved_names](https://developer.wordpress.org/reference/hooks/subdirectory_reserved_names/) * Filters reserved site names on a sub-directory Multisite installation. * Used by [1 function](https://developer.wordpress.org/reference/hooks/subdirectory_reserved_names/#used-by) | Uses [0 functions](https://developer.wordpress.org/reference/hooks/subdirectory_reserved_names/#uses) | Source: [wp-includes/ms-functions.php:2768](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-functions.php#L2768-L2768) * hook[newblogname](https://developer.wordpress.org/reference/hooks/newblogname/) * Filters the new site name during registration. * Used by [1 function](https://developer.wordpress.org/reference/hooks/newblogname/#used-by) | Uses [0 functions](https://developer.wordpress.org/reference/hooks/newblogname/#uses) | 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