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.. rst-class:: align-right

built-in predicate

.. index:: pair: threaded_cancel/1; Built-in predicate .. _predicates_threaded_cancel_1:

threaded_cancel/1

Description

::

threaded_cancel(Tag)

Cancels a tagged threaded call. When there is no asynchronous call with the given tag, calling this predicate succeeds assuming the asynchronous call have already terminated or canceled. The threaded call identifier tag is generated by calls to the :ref:`threaded_call/2 <predicates_threaded_call_1_2>` and :ref:`threaded_once/2 <predicates_threaded_once_1_2>` predicates. Tags shall be regarded as an opaque term; 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:`threads <flag_threads>` flag is set to supported when that is the case.

Modes and number of proofs

::

threaded_cancel(+nonvar) - one

Errors

| Tag is a variable: | instantiation_error

Examples

(none)

.. seealso::

:ref:predicates_threaded_call_1_2, :ref:predicates_threaded_exit_1_2, :ref:predicates_threaded_ignore_1, :ref:predicates_threaded_once_1_2, :ref:predicates_threaded_1