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 returned by std::promise::get_future(), std::packaged_task::get_future() or std::async() until the first time get()or share() is called.

Contents

[edit] Parameters

(none)

[edit] Return value

true if *this refers to a shared state, otherwise false.

[edit] Exceptions

noexcept specification:  
noexcept
  (since C++11)

[edit] Example

[edit] See also

waits for the result to become available
(public member function)