1 //===----------------------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 // <future>
11 
12 // class promise<R>
13 
14 // void promise<R&>::set_value(R& r);
15 
16 #include <future>
17 #include <cassert>
18 
main()19 int main()
20 {
21     {
22         typedef int& T;
23         int i = 3;
24         std::promise<T> p;
25         std::future<T> f = p.get_future();
26         p.set_value(i);
27         int& j = f.get();
28         assert(j == 3);
29         ++i;
30         assert(j == 4);
31         try
32         {
33             p.set_value(i);
34             assert(false);
35         }
36         catch (const std::future_error& e)
37         {
38             assert(e.code() == make_error_code(std::future_errc::promise_already_satisfied));
39         }
40     }
41 }
42