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std::future_error - cppreference.com

From cppreference.com

class future_error;

 (since C++11)

The class std::future_error defines an exception object that is thrown on failure by the functions in the thread library that deal with asynchronous execution and shared states (std::future, std::promise, etc). Similar to std::system_error, this exception carries an error code compatible with std::error_code.

cpp/error/exceptioncpp/error/logic error

Inheritance diagram

Member functions

creates a std::future_error object
(public member function) [edit]
replaces the std::future_error object
(public member function) [edit]
returns the error code
(public member function) [edit]
returns the explanatory string specific to the error code
(public member function) [edit]

Inherited from std::logic_error

Inherited from std::exception

Member functions

destroys the exception object
(virtual public member function of std::exception) [edit]
returns an explanatory string
(virtual public member function of std::exception) [edit]

Example

#include <future>
#include <iostream>

int main()
{
    std::future<int> empty;
    try
    {
        int n = empty.get(); // The behavior is undefined, but
                             // some implementations throw std::future_error
    }
    catch (const std::future_error& e)
    {
        std::cout << "Caught a future_error with code \"" << e.code()
                  << "\"\nMessage: \"" << e.what() << "\"\n";
    }
}

Possible output: 

Caught a future_error with code "future:3"
Message: "No associated state"

See also