c('PL_clear_exception')

Documentation
- Reference manual
  - Foreign Language Interface
    - The Foreign Include File
      - Prolog exceptions in foreign code
        
        PL_raise_exception()
        
        PL_throw()
        
        PL_exception()
        
        PL_clear_exception()
- Packages

below opens a query to the predicate is_a/2 to find the ancestor of‘me'. The reference to the predicate is valid for the duration of the process or until PL_cleanup()