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 // <functional>
10 
11 // reference_wrapper
12 
13 // template <class... ArgTypes>
14 //   requires Callable<T, ArgTypes&&...>
15 //   Callable<T, ArgTypes&&...>::result_type
16 //   operator()(ArgTypes&&... args) const;
17 
18 #include <functional>
19 #include <cassert>
20 
21 // 0 args, return void
22 
23 int count = 0;
24 
25 void f_void_0()
26 {
27     ++count;
28 }
29 
30 struct A_void_0
31 {
32     void operator()() {++count;}
33 };
34 
35 void
36 test_void_0()
37 {
38     int save_count = count;
39     // function
40     {
41     std::reference_wrapper<void ()> r1(f_void_0);
42     r1();
43     assert(count == save_count+1);
44     save_count = count;
45     }
46     // function pointer
47     {
48     void (*fp)() = f_void_0;
49     std::reference_wrapper<void (*)()> r1(fp);
50     r1();
51     assert(count == save_count+1);
52     save_count = count;
53     }
54     // functor
55     {
56     A_void_0 a0;
57     std::reference_wrapper<A_void_0> r1(a0);
58     r1();
59     assert(count == save_count+1);
60     save_count = count;
61     }
62 }
63 
64 int main(int, char**)
65 {
66     test_void_0();
67 
68   return 0;
69 }
70