WordPress at a glance
function is not described

install_blog() WP 3.0.0

Deprecated in 5.1.0. It is no longer supported and can be removed in future releases. It is recommended to replace this function with the same one.

Install an empty blog.

Creates the new blog tables and options. If calling this function directly, be sure to use switch_to_blog() first, so that $wpdb points to the new blog.

  • Global. wpdb. $wpdb
  • Global. WP_Roles. $wp_roles

No Hooks.

Return

Nothing (null).

Usage

install_blog( $blog_id, $blog_title );
$blog_id(int) (required)
The value returned by wp_insert_site().
$blog_title(string)
The title of the new site.
Default: ''

Code of install blog: wp-includes/ms-deprecated.php WP 5.2.2

<?php
function install_blog( $blog_id, $blog_title = '' ) {
	global $wpdb, $wp_roles;

	_deprecated_function( __FUNCTION__, '5.1.0' );

	// Cast for security
	$blog_id = (int) $blog_id;

	require_once( ABSPATH . 'wp-admin/includes/upgrade.php' );

	$suppress = $wpdb->suppress_errors();
	if ( $wpdb->get_results( "DESCRIBE {$wpdb->posts}" ) ) {
		die( '<h1>' . __( 'Already Installed' ) . '</h1><p>' . __( 'You appear to have already installed WordPress. To reinstall please clear your old database tables first.' ) . '</p></body></html>' );
	}
	$wpdb->suppress_errors( $suppress );

	$url = get_blogaddress_by_id( $blog_id );

	// Set everything up
	make_db_current_silent( 'blog' );
	populate_options();
	populate_roles();

	// populate_roles() clears previous role definitions so we start over.
	$wp_roles = new WP_Roles();

	$siteurl = $home = untrailingslashit( $url );

	if ( ! is_subdomain_install() ) {

		if ( 'https' === parse_url( get_site_option( 'siteurl' ), PHP_URL_SCHEME ) ) {
			$siteurl = set_url_scheme( $siteurl, 'https' );
		}
		if ( 'https' === parse_url( get_home_url( get_network()->site_id ), PHP_URL_SCHEME ) ) {
			$home = set_url_scheme( $home, 'https' );
		}
	}

	update_option( 'siteurl', $siteurl );
	update_option( 'home', $home );

	if ( get_site_option( 'ms_files_rewriting' ) ) {
		update_option( 'upload_path', UPLOADBLOGSDIR . "/$blog_id/files" );
	} else {
		update_option( 'upload_path', get_blog_option( get_network()->site_id, 'upload_path' ) );
	}

	update_option( 'blogname', wp_unslash( $blog_title ) );
	update_option( 'admin_email', '' );

	// remove all perms
	$table_prefix = $wpdb->get_blog_prefix();
	delete_metadata( 'user', 0, $table_prefix . 'user_level', null, true ); // delete all
	delete_metadata( 'user', 0, $table_prefix . 'capabilities', null, true ); // delete all
}