WordPress at a glance
function is not described

validate_blog_form() WP 3.0.0

Validate the new site signup

No Hooks.

Return

Array. Contains the new site data and error messages.

Usage

validate_blog_form();

Code of validate blog form: wp-signup.php VER 5.0.3

<?php
function validate_blog_form() {
	$user = '';
	if ( is_user_logged_in() )
		$user = wp_get_current_user();

	return wpmu_validate_blog_signup($_POST['blogname'], $_POST['blog_title'], $user);
}