SWI-Prolog -- API-function PL_foreign

Documentation
- Reference manual
  - Foreign Language Interface
    - The Foreign Include File
      - Argument Passing and Control
        
        Non-deterministic Foreign Predicates
        
        PL_retry()
        
        PL_retry_address()
        
        PL_foreign_control()
        
        PL_foreign_context()
        
        PL_foreign_context_address()
        
        PL_foreign_context_predicate()
- Packages

Availability:C-language interface function

int PL_foreign_control(control_t)

Extracts the type of call from the control argument. The return values are described above. Note that the function should be prepared to handle the PL_PRUNED case and should be aware that the other arguments are not valid in this case.