std::shared_future<T>::valid

Since C++11

Checks if the future refers to a shared state.

# Declarations

bool valid() const noexcept;

(since C++11)

# Return value

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

# Example

#include <future>
#include <iostream>
 
int main()
{
    std::promise<void> p;
    std::shared_future<void> f = p.get_future();
 
    std::cout << std::boolalpha;
 
    std::cout << f.valid() << '\n';
    p.set_value();
    std::cout << f.valid() << '\n';
    f.get();
    std::cout << f.valid() << '\n';
}

# See also

wait