SWI-Prolog -- term

Documentation
- Reference manual
  - Constraint Logic Programming
    - Attributed variables
      - Operations on terms with attributed variables
        
        copy_term/3
        
        copy_term_nat/2
        
        term_attvars/2
- Packages

Availability:built-in

term_attvars(+Term, -AttVars)

AttVars is a list of all attributed variables in Term and its attributes. That is, term_attvars/2 works recursively through attributes. This predicate is cycle-safe. The goal term_attvars(Term,[]) in an efficient test that Term has no attributes; scanning the term is aborted after the first attributed variable is found.