If Prolog encounters a foreign predicate at run time it will call a
function specified in the predicate definition of the foreign predicate.
The arguments 1, ... , <arity> pass the
Prolog arguments to the goal as Prolog terms. Foreign functions should
be declared of type
foreign_t
. Deterministic foreign functions have two
alternatives to return control back to Prolog:
return TRUE
.
return FALSE
.