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_at_thread_exit(R& r);
17 
18 #include <future>
19 #include <memory>
20 #include <cassert>
21 
22 int i = 0;
23 
func(std::promise<int &> p)24 void func(std::promise<int&> p)
25 {
26     p.set_value_at_thread_exit(i);
27     i = 4;
28 }
29 
main()30 int main()
31 {
32     {
33         std::promise<int&> p;
34         std::future<int&> f = p.get_future();
35         std::thread(func, std::move(p)).detach();
36         assert(f.get() == 4);
37     }
38 }
39