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 // UNSUPPORTED: libcpp-has-no-threads
11 
12 // <future>
13 
14 // class promise<R>
15 
16 // void promise<R&>::set_value(R& r);
17 
18 #include <future>
19 #include <cassert>
20 
main()21 int main()
22 {
23     {
24         typedef int& T;
25         int i = 3;
26         std::promise<T> p;
27         std::future<T> f = p.get_future();
28         p.set_value(i);
29         int& j = f.get();
30         assert(j == 3);
31         ++i;
32         assert(j == 4);
33         try
34         {
35             p.set_value(i);
36             assert(false);
37         }
38         catch (const std::future_error& e)
39         {
40             assert(e.code() == make_error_code(std::future_errc::promise_already_satisfied));
41         }
42     }
43 }
44