Passing Data to and from External Predicates in C++

## B.4 Passing Data to and from External Predicates in C++

These two functions are only meaningful inside C++ functions that have been called from ECLiPSe as external predicates.

EC_word EC_arg(int i)
  If inside a C++ function called from ECLiPSe, this returns the i’th argument of the call.
int unify(EC_word,EC_word)
  Unify the two given pwords. Note that, if attributed variables are involved in the unification, the associated unification handlers as well as subsequent waking will only happen once control is returned to ECLiPSe.
int EC_word::unify(EC_word)
  Similar, but a method of EC_word.