#include <iostream>
#include <cstdlib>
//---------------------------------------------------------------------------
#include <future>
#include <stdexcept>
//------------------------------------------------------------------------------
std::future<int> test_future_error1()
{
    std::promise<int> prom;
	std::future<int> fu = prom.get_future();

	prom.set_value(5566);

	return fu;
}
//---------------------------------------------------------------
std::future<int> test_future_error2()
{
	std::promise<int> prom;
	std::future<int> fu = prom.get_future();
	std::future<int> fu2 = prom.get_future();	// throw std::future_errc::future_already_retrieved

	prom.set_value(5566);

	return fu;
}
//---------------------------------------------------------------
std::future<int> test_future_error3()
{
	std::promise<int> prom;
	std::future<int> fu = prom.get_future();

	prom.set_value(5566);
	prom.set_value(7788);	// throw std::future_errc::promise_already_satisfied

	return fu;
}
//---------------------------------------------------------------
std::future<int> test_future_error4()
{
	std::promise<int> prom;
	std::future<int> fu = prom.get_future();

	return fu;
}	// throw std::future_errc::broken_promise at fu.get()
//---------------------------------------------------------------
std::future<int> test_future_error5()
{
	std::future<int> fu;

	return fu;
}	// throw std::future_errc::no_state at fu.get()
//---------------------------------------------------------------
int main()
{
	try {

		std::future<int> fu = test_future_error3();
		int a = fu.get();

		std::cout << "a= " << a << std::endl;
	} catch(const std::future_error &e) {

		std::cout << "future_error:" << std::endl;
		if( e.code() == std::future_errc::broken_promise )
			std::cout << "code() == std::future_errc::broken_promise" << std::endl;
		else if( e.code() == std::future_errc::future_already_retrieved )
			std::cout << "code() == std::future_errc::future_already_retrieved" << std::endl;
		else if( e.code() == std::future_errc::promise_already_satisfied )
			std::cout << "code() == std::future_errc::promise_already_satisfied" << std::endl;
		else if( e.code() == std::future_errc::no_state )
			std::cout << "code() == std::future_errc::no_state" << std::endl;
		else
			std::cout << "code() == unknown" << std::endl;
		std::cout << "what() == " << e.what() << std::endl;

	} catch(const std::exception &e) {
		std::cout << "excepton: " << e.what() << std::endl;
	}

	return 0;
}