bp_blogs_validate_blog_signup()

function bp_blogs_validate_blog_signup() {
	global $wpdb, $current_user, $blogname, $blog_title, $errors, $domain, $path, $current_site;

	if ( !check_admin_referer( 'bp_blog_signup_form' ) )
		return false;

	$current_user = wp_get_current_user();

	if( !is_user_logged_in() )
		die();

	$result = bp_blogs_validate_blog_form();
	extract($result);

	if ( $errors->get_error_code() ) {
		unset($_POST['submit']);
		bp_show_blog_signup_form( $blogname, $blog_title, $errors );
		return false;
	}

	$public = (int) $_POST['blog_public'];

	// Depreciated.
	$meta = apply_filters( 'signup_create_blog_meta', array( 'lang_id' => 1, 'public' => $public ) );

	/**
	 * Filters the default values for Blog meta.
	 *
	 * @since BuddyPress 1.0.0
	 *
	 * @param array $meta {
	 *      string $value  Default blog language ID.
	 *      string $public Default public status.
	 * }
	 */
	$meta = apply_filters( 'add_signup_meta', $meta );

	// If this is a subdomain install, set up the site inside the root domain.
	if ( is_subdomain_install() )
		$domain = $blogname . '.' . preg_replace( '|^www\.|', '', $current_site->domain );

	$blog_id = wpmu_create_blog( $domain, $path, $blog_title, $current_user->ID, $meta, $wpdb->siteid );
	bp_blogs_confirm_blog_signup( $domain, $path, $blog_title, $current_user->user_login, $current_user->user_email, $meta, $blog_id );
	return true;
}