How do you get the Logged in User Id from a PL-SQL package that is called from WebCenter Portal to u

We are upgrading from Portal 9i to WebCenter Portal.  The new WebCenter portal forms call a 'api' PL-SQL package that does all the database updates for the forms.  Part of the current code we use the Portal API to get the user like:

v_user_id := portal.wwctx_api.get_user_id;

How do we do this in the new WebCenter Portal environment?