built-in predicate
threaded_exit/1-2
Description
threaded_exit(Goal)
threaded_exit(Goal, Tag)
Retrieves the result of proving Goal
in a new thread. This predicate
blocks execution until the reply is sent to the this message queue
by the thread executing the goal. When there is no thread proving the goal,
the predicate generates an exception. This predicate is non-deterministic,
providing access to any alternative solutions of its argument.
The argument of this predicate should be a variant of the argument of
the corresponding threaded_call/1
or threaded_once/1 call.
When the predicate argument is subsumed by the threaded_call/1
or
threaded_once/1
call argument, the threaded_exit/1
call will
succeed iff its argument is a solution of the (more general) goal.
The threaded_exit/2
variant accepts a threaded call identifier tag
generated by the calls to the threaded_call/2
and threaded_once/2 predicates. Tags
shall be regarded as an opaque term; users shall not rely on its 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_exit(+callable) - zero_or_more
threaded_exit(+callable, +nonvar) - zero_or_more
Errors
Goal
is a variable:instantiation_error
Goal
is neither a variable nor a callable term:type_error(callable, Goal)
Goal
in the Object
calling context:existence_error(thread, Object)
Tag
is a variable:instantiation_error
Examples
threaded_exit(Goal)
threaded_exit(::Goal)
threaded_exit(Object::Goal)