built-in predicate

# `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 backend Prolog compiler providing compatible multi-threading primitives. The value of the read-only 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), ...

See also

threaded_engine_post/2