wp_create_user()

Function: A simpler way of inserting a user into the database.

Source: wp-includes/user.php:1970

profile_update

Action Hook: Fires immediately after an existing user is updated.

Source: wp-includes/user.php:1708

wp_update_user()

Function: Update a user in the database.

Source: wp-includes/user.php:1739

username_exists()

Function: Checks whether the given username exists.

Source: wp-includes/user.php:1313

wp_insert_user()

Function: Insert a user into the database.

Source: wp-includes/user.php:1411

get_user_option()

Function: Retrieve user option that can be either per Site or per Network.

Source: wp-includes/user.php:451

update_user_option()

Function: Update user option with global blog capability.

Source: wp-includes/user.php:506

get_attachment_template()

Function: Retrieve path of attachment template in current or parent template.

Source: wp-includes/template.php:593

wp_delete_category()

Function: Deletes one existing category.

Source: wp-includes/taxonomy.php:1802

in_the_loop()

Function: Whether the caller is in the Loop.

Source: wp-includes/query.php:780