user_register action-hook . WP 1.5.0

Fires immediately after a new user is registered.

Usage

add_action( 'user_register', 'action_function_name_3994' );
function action_function_name_3994( $user_id ){
	// action...
}

$user_id(int)

User ID.

Where the hook is called

do_action( 'user_register', $user_id );

Where the hook is used (in WP core)

add_action( 'user_register', array( 'WP_Internal_Pointers', 'dismiss_pointers_for_new_users' ) );

add_action( $action, 'wp_maybe_update_network_user_counts', 10, 0 );