Registration Form Validation in wordpress

Question

I have validate the custom field in registration form, I read out the codex of wordpress so that itself i do this way. But I figure out it throws error like this one

Call to a member function add() on a non-object 

I don't know why this should happen. How can I fix this? Any Suggestion would be great.

Code:

function myplugin_check_fields($errors, $sanitized_user_login, $user_email) {

        $errors->add( 'demo_error', __('<strong>ERROR</strong>: This is a demo error. Registration halted.','mydomain') );

        return $errors;

    }

    add_filter('registration_errors', 'myplugin_check_fields', 10, 3);

Answer 1

Make Global or get global permissions to the object responsible for the instance of add() global $wp_object_responsible;

    function myplugin_check_fields($errors, $sanitized_user_login, $user_email) {
        global $wp_object_responsible;  //edit here

$errors->add( 'demo_error', __('<strong>ERROR</strong>: This is a demo error. Registration halted.','mydomain') );

            return $errors;