built-in predicate

# `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 has already terminated or canceled. The threaded call identifier tag is generated by calls to the threaded_call/2 and threaded_once/2 predicates. Tags shall be regarded as an opaque term; users shall not rely on their type.

Note

This predicate requires a backend Prolog compiler providing compatible multi-threading primitives. The value of the read-only 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)

See also

threaded_call/1-2, threaded_exit/1-2, threaded_ignore/1, threaded_once/1-2, threaded/1