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.. rst-class:: align-right

built-in predicate

.. index:: pair: threaded_engine_fetch/1; Built-in predicate .. _predicates_threaded_engine_fetch_1:

threaded_engine_fetch/1

Description

::

threaded_engine_fetch(Term)

Fetches a term from the engine term queue. Blocks until a term is available. Fails if not called from within an engine.

.. 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.

Modes and number of proofs

::

threaded_engine_fetch(?term) - zero_or_one

Errors

(none)

Examples

::

% fetch a term from the engine term queue: ..., threaded_engine_fetch(Term), ...

.. seealso::

:ref:predicates_threaded_engine_post_2