1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 // UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
10 
11 // <functional>
12 //
13 // reference_wrapper
14 //
15 // template <ObjectType T> reference_wrapper<T> ref(T& t);
16 //
17 //  where T is an incomplete type (since C++20)
18 
19 #include <functional>
20 #include <cassert>
21 
22 
23 struct Foo;
24 
25 Foo& get_foo();
26 
27 void test() {
28     Foo& foo = get_foo();
29     std::reference_wrapper<Foo> ref = std::ref(foo);
30     assert(&ref.get() == &foo);
31 }
32 
33 struct Foo { };
34 
35 Foo& get_foo() {
36     static Foo foo;
37     return foo;
38 }
39 
40 int main() {
41     test();
42 }
43