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 // template<Returnable R, class T, CopyConstructible... Args>
12 //   unspecified mem_fn(R (T::* pm)(Args...));
13 
14 #include <functional>
15 #include <cassert>
16 
17 #include "test_macros.h"
18 
19 struct A
20 {
21     char test0() {return 'a';}
22     char test1(int) {return 'b';}
23     char test2(int, double) {return 'c';}
24 };
25 
26 template <class F>
27 void
28 test0(F f)
29 {
30     {
31     A a;
32     assert(f(a) == 'a');
33     A* ap = &a;
34     assert(f(ap) == 'a');
35     const F& cf = f;
36     assert(cf(ap) == 'a');
37     }
38 }
39 
40 template <class F>
41 void
42 test1(F f)
43 {
44     {
45     A a;
46     assert(f(a, 1) == 'b');
47     A* ap = &a;
48     assert(f(ap, 2) == 'b');
49     const F& cf = f;
50     assert(cf(ap, 2) == 'b');
51     }
52 }
53 
54 template <class F>
55 void
56 test2(F f)
57 {
58     {
59     A a;
60     assert(f(a, 1, 2) == 'c');
61     A* ap = &a;
62     assert(f(ap, 2, 3.5) == 'c');
63     const F& cf = f;
64     assert(cf(ap, 2, 3.5) == 'c');
65     }
66 }
67 
68 int main(int, char**)
69 {
70     test0(std::mem_fn(&A::test0));
71     test1(std::mem_fn(&A::test1));
72     test2(std::mem_fn(&A::test2));
73 #if TEST_STD_VER >= 11
74     static_assert((noexcept(std::mem_fn(&A::test0))), ""); // LWG#2489
75 #endif
76 
77   return 0;
78 }
79