get_main_site_id( int $network_id = null )

Gets the main site ID.

Parameters

$network_id

(int) (Optional) The ID of the network for which to get the main site. Defaults to the current network.

Default value: null

Return

(int) The ID of the main site.

Source

File: wp-includes/functions.php 

function get_main_site_id( $network_id = null ) {
	if ( ! is_multisite() ) {
		return get_current_blog_id();
	}

	$network = get_network( $network_id );
	if ( ! $network ) {
		return 0;
	}

	return $network->site_id;
}

Expand Source Code View on GitHub

Related

Uses

Uses
Uses Description
wp-includes/ms-blogs.php: get_network()

Retrieves network data given a network ID or network object.
wp-includes/load.php: is_multisite()

If Multisite is enabled.
wp-includes/load.php: get_current_blog_id()

Retrieve the current site ID.

Used By

Used By
Used By Description
wp-includes/ms-load.php: ms_load_current_site_and_network()

Identifies the network and site of a requested domain and path and populates the corresponding network and site global objects as part of the multisite bootstrap process.
wp-includes/functions.php: is_main_site()

Determine whether a site is the main site of the current network.

Changelog

Changelog
Version Description
WP-4.9.0 Introduced.