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.. rst-class:: align-right

built-in predicate

.. index:: pair: threaded_engine_create/3; Built-in predicate .. _predicates_threaded_engine_create_3:

threaded_engine_create/3

Description

::

threaded_engine_create(AnswerTemplate, Goal, Engine)

Creates a new engine for proving the given goal and defines an answer template for retrieving the goal solution bindings. A message queue for passing arbitrary terms to the engine is also created. If the name for the engine is not given, a unique name is generated and returned. Engine names shall be regarded as opaque terms; users shall not rely on its type.

.. note::

This predicate requires a :term:`backend Prolog compiler` providing compatible multi-threading primitives. The value of the read-only :ref:`engines <flag_engines>` flag is set to supported when that is the case.

Meta-predicate template

::

threaded_engine_create(*, 0, *)

Modes and number of proofs

::

threaded_engine_create(@term, @callable, @nonvar) - one threaded_engine_create(@term, @callable, --nonvar) - one

Errors

| Goal is a variable: | instantiation_error | Goal is neither a variable nor a callable term: | type_error(callable, Goal) | Engine is the name of an existing engine: | permission_error(create, engine, Engine)

Examples

::

% create a new engine to enumerate list elements: | ?- threaded_engine_create(X, member(X, [1,2,3]), worker_1).

.. seealso::

:ref:predicates_threaded_engine_destroy_1, :ref:predicates_threaded_engine_self_1, :ref:predicates_threaded_engine_1, :ref:predicates_threaded_engine_next_2, :ref:predicates_threaded_engine_next_reified_2