tmp/tmpz1jt3yo4/{from.md → to.md}
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| 1 |
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#### General <a id="futures.task.general">[[futures.task.general]]</a>
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The class template `packaged_task` defines a type for wrapping a
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function or callable object so that the return value of the function or
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callable object is stored in a future when it is invoked.
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When the `packaged_task` object is invoked, its stored task is invoked
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and the result (whether normal or exceptional) stored in the shared
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state. Any futures that share the shared state will then be able to
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access the stored result.
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``` cpp
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namespace std {
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template<class> class packaged_task; // not defined
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template<class R, class... ArgTypes>
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class packaged_task<R(ArgTypes...)> {
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public:
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// construction and destruction
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packaged_task() noexcept;
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template<class F>
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explicit packaged_task(F&& f);
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~packaged_task();
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// no copy
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packaged_task(const packaged_task&) = delete;
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packaged_task& operator=(const packaged_task&) = delete;
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// move support
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packaged_task(packaged_task&& rhs) noexcept;
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packaged_task& operator=(packaged_task&& rhs) noexcept;
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void swap(packaged_task& other) noexcept;
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bool valid() const noexcept;
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// result retrieval
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future<R> get_future();
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// execution
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void operator()(ArgTypes... );
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void make_ready_at_thread_exit(ArgTypes...);
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void reset();
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};
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template<class R, class... ArgTypes>
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packaged_task(R (*)(ArgTypes...)) -> packaged_task<R(ArgTypes...)>;
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template<class F> packaged_task(F) -> packaged_task<see below>;
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}
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```
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