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++03, c++11
10 #include <functional>
11 #include <string>
12 
13 #include "test_macros.h"
14 
15 template <class T>
16 struct is_transparent
17 {
18 private:
19     struct two {char lx; char lxx;};
20     template <class U> static two test(...);
21     template <class U> static char test(typename U::is_transparent* = 0);
22 public:
23     static const bool value = sizeof(test<T>(0)) == 1;
24 };
25 
26 
27 int main(int, char**)
28 {
29     static_assert ( !is_transparent<std::less<int>>::value, "" );
30     static_assert ( !is_transparent<std::less<std::string>>::value, "" );
31     static_assert (  is_transparent<std::less<void>>::value, "" );
32     static_assert (  is_transparent<std::less<>>::value, "" );
33 
34     static_assert ( !is_transparent<std::less_equal<int>>::value, "" );
35     static_assert ( !is_transparent<std::less_equal<std::string>>::value, "" );
36     static_assert (  is_transparent<std::less_equal<void>>::value, "" );
37     static_assert (  is_transparent<std::less_equal<>>::value, "" );
38 
39     static_assert ( !is_transparent<std::equal_to<int>>::value, "" );
40     static_assert ( !is_transparent<std::equal_to<std::string>>::value, "" );
41     static_assert (  is_transparent<std::equal_to<void>>::value, "" );
42     static_assert (  is_transparent<std::equal_to<>>::value, "" );
43 
44     static_assert ( !is_transparent<std::not_equal_to<int>>::value, "" );
45     static_assert ( !is_transparent<std::not_equal_to<std::string>>::value, "" );
46     static_assert (  is_transparent<std::not_equal_to<void>>::value, "" );
47     static_assert (  is_transparent<std::not_equal_to<>>::value, "" );
48 
49     static_assert ( !is_transparent<std::greater<int>>::value, "" );
50     static_assert ( !is_transparent<std::greater<std::string>>::value, "" );
51     static_assert (  is_transparent<std::greater<void>>::value, "" );
52     static_assert (  is_transparent<std::greater<>>::value, "" );
53 
54     static_assert ( !is_transparent<std::greater_equal<int>>::value, "" );
55     static_assert ( !is_transparent<std::greater_equal<std::string>>::value, "" );
56     static_assert (  is_transparent<std::greater_equal<void>>::value, "" );
57     static_assert (  is_transparent<std::greater_equal<>>::value, "" );
58 
59     return 0;
60 }
61