SWI-Prolog -- API-function Sferror

Documentation
- Reference manual
  - Foreign Language Interface
    - Foreign access to Prolog IO streams
      - Foreign stream error handling
        
        Sferror()
        
        Sclearerr()
        
        Sseterr()
        
        Sset_exception()
- Packages

Availability:C-language interface function

int Sferror(IOSTREAM *s)

Returns TRUE if the stream is in an error condition, FALSE if the stream is valid and in normal condition and -1 if the stream is invalid.