std::packaged_task<R(Args...)>::operator()

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Concurrency support library

Threads

thread

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(C++20)

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(C++17)(C++17)

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atomic_flag_clearatomic_flag_clear_explicit (C++11)(C++11)
atomic_flag_testatomic_flag_test_explicit (C++20)(C++20)
atomic_flag_waitatomic_flag_wait_explicit (C++20)(C++20)
atomic_flag_notify_one (C++20)
atomic_flag_notify_all (C++20)

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std::packaged_task

Member functions
packaged_task::packaged_task
packaged_task::~packaged_task
packaged_task::operator=
packaged_task::valid
packaged_task::swap
Getting the result
packaged_task::get_future
Execution
packaged_task::operator()
packaged_task::make_ready_at_thread_exit
packaged_task::reset
Non-member functions
swap(std::packaged_task)
Helper classes
uses_allocator<std::packaged_task> (until C++17)
Deduction guides(C++17)

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void operator()( ArgTypes...args);		(since C++11)

Calls the stored task as if byINVOKE<R>(f, args...), wheref is the stored task. The return value of the task or any exceptions thrown are stored in the shared state. The shared state is made ready and any threads waiting for this are unblocked.

[edit]Parameters

args

the parameters to pass on invocation of the stored task

[edit]Return value

(none)

[edit]Exceptions

std::future_error on the following error conditions:

The stored task has already been invoked. The error category is set topromise_already_satisfied.
*this has no shared state. The error category is set tono_state.

[edit]Example

This section is incomplete
Reason: no example

[edit]Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 2142	C++11	a successful call tooperator() synchronized with a call to any member function of astd::future or std::shared_future that share their shared state with*this	no additional synchronization guarantees other than what is already provided by shared state