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: c++98, c++03, c++11
11 #include <functional>
12 #include <string>
13 
14 template <class T>
15 struct is_transparent
16 {
17 private:
18     struct two {char lx; char lxx;};
19     template <class U> static two test(...);
20     template <class U> static char test(typename U::is_transparent* = 0);
21 public:
22     static const bool value = sizeof(test<T>(0)) == 1;
23 };
24 
25 
26 int main ()
27 {
28     static_assert ( !is_transparent<std::plus<int>>::value, "" );
29     static_assert ( !is_transparent<std::plus<std::string>>::value, "" );
30     static_assert (  is_transparent<std::plus<void>>::value, "" );
31     static_assert (  is_transparent<std::plus<>>::value, "" );
32 
33     static_assert ( !is_transparent<std::minus<int>>::value, "" );
34     static_assert ( !is_transparent<std::minus<std::string>>::value, "" );
35     static_assert (  is_transparent<std::minus<void>>::value, "" );
36     static_assert (  is_transparent<std::minus<>>::value, "" );
37 
38     static_assert ( !is_transparent<std::multiplies<int>>::value, "" );
39     static_assert ( !is_transparent<std::multiplies<std::string>>::value, "" );
40     static_assert (  is_transparent<std::multiplies<void>>::value, "" );
41     static_assert (  is_transparent<std::multiplies<>>::value, "" );
42 
43     static_assert ( !is_transparent<std::divides<int>>::value, "" );
44     static_assert ( !is_transparent<std::divides<std::string>>::value, "" );
45     static_assert (  is_transparent<std::divides<void>>::value, "" );
46     static_assert (  is_transparent<std::divides<>>::value, "" );
47 
48     static_assert ( !is_transparent<std::modulus<int>>::value, "" );
49     static_assert ( !is_transparent<std::modulus<std::string>>::value, "" );
50     static_assert (  is_transparent<std::modulus<void>>::value, "" );
51     static_assert (  is_transparent<std::modulus<>>::value, "" );
52 
53     static_assert ( !is_transparent<std::negate<int>>::value, "" );
54     static_assert ( !is_transparent<std::negate<std::string>>::value, "" );
55     static_assert (  is_transparent<std::negate<void>>::value, "" );
56     static_assert (  is_transparent<std::negate<>>::value, "" );
57 
58     return 0;
59 }
60