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filter is not described

user_(field) filter-hook . WP 2.9.0

Filters the value of a user field in a standard context.

The dynamic portion of the hook name, $field, refers to the prefixed user field being filtered, such as 'user_login', 'user_email', 'first_name', etc.

Usage

add_filter( 'user_(field)', 'filter_function_name_2248', 10, 3 );
function filter_function_name_2248( $value, $user_id, $context ){
	// filter...

	return $value;
}
$value(mixed)
The user object value to sanitize.
$user_id(int)
User ID.
$context(string)
The context to filter within.

Where the hook is called

sanitize_user_field()
wp-includes/user.php 1247
$value = apply_filters( "user_{$field}", $value, $user_id, $context );

Where the hook is used (in WP core)

wp-includes/default-filters.php 348
add_action( 'user_request_action_confirmed', '_wp_privacy_account_request_confirmed' );
wp-includes/default-filters.php 349
add_action( 'user_request_action_confirmed', '_wp_privacy_send_request_confirmation_notification', 12 ); // After request marked as completed.
wp-includes/default-filters.php 565
add_filter( 'user_has_cap', 'wp_maybe_grant_install_languages_cap', 1 );
wp-admin/includes/ms-admin-filters.php 14
add_action( 'user_admin_notices', 'new_user_email_admin_notice' );
wp-admin/includes/admin-filters.php 97
add_action( 'user_register', array( 'WP_Internal_Pointers', 'dismiss_pointers_for_new_users' ) );