wp_validate_logged_in_cookie()

wp_validate_logged_in_cookie() — Validates the logged-in cookie. Checks the logged-in cookie if the previous auth cookie could not be validated and parsed. This is a callback for the ‘determine_current_user’ filter, rather than API.

Inputs: $user_id (int|false): The user ID (or false) as received from the determine_current_user filter.

Returns int|false: User ID if validated, false otherwise. If a user ID from an earlier filter callback is received, that value is returned.