XPLMFeatureEnumerator f

XPLMFeatureEnumerator_f

typedef void (* XPLMFeatureEnumerator_f)(
                                   const char *         inFeature,    
                                   void *               inRef);    

You pass an XPLMFeatureEnumerator_f to get a list of all features supported by a given version running version of X-Plane. This routine is called once for each feature.