std::future::valid
From cppreference.com
| bool valid() const;
|
(since C++11) | |
Checks if the future refers to a shared state.
This is the case only for futures that were not default-constructed or moved from (i.e. returned by std::promise::get_future(), std::packaged_task::get_future() or std::async()) until the first time get() or share() is called.
The behavior is undefined if any member function other than the destructor, the move-assignment operator, or valid is called on a future that does not refer to shared state (although implementations are encouraged to throw std::future_error indicating no_state in this case).
Contents |
[edit] Parameters
(none)
[edit] Return value
true if *this refers to a shared state, otherwise false.
[edit] Exceptions
noexcept specification:
noexcept
[edit] Example
| This section is incomplete Reason: no example |
[edit] See also
| waits for the result to become available (public member function) |