WordPress at a glance
function is not described

get_user_count() WP 3.0.0

The number of active users in your installation.

The count is cached and updated twice daily. This is not a live count.

  • Since 4.8.0 The $network_id parameter has been added.

No Hooks.

Return

Int. Number of active users on the network.

Usage

get_user_count( $network_id );
$network_id(int/null)
ID of the network.
Default: current network

Code of get user count: wp-includes/ms-functions.php VER 5.1.1

<?php
function get_user_count( $network_id = null ) {
	return get_network_option( $network_id, 'user_count' );
}