Retrieves an answer from an engine and signals it to start computing the
next answer. This predicate always succeeds and blocks until an answer
becomes available. Answers are returned using the terms
Modes and number of proofs
threaded_engine_next_reified(@nonvar, ?nonvar) - one
Engineis a variable:
Engineis neither a variable nor the name of an existing engine:
% get the next reified answer from the worker_1 engine: | ?- threaded_engine_next_reified(worker_1, Answer).