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 // <functional>
11 
12 // template <class T>
13 // struct hash
14 //     : public unary_function<T, size_t>
15 // {
16 //     size_t operator()(T val) const;
17 // };
18 
19 // Not very portable
20 
21 #include <string>
22 #include <cassert>
23 #include <type_traits>
24 
25 template <class T>
26 void
test()27 test()
28 {
29     typedef std::hash<T> H;
30     static_assert((std::is_base_of<std::unary_function<T, std::size_t>,
31                                    H>::value), "");
32     H h;
33     std::string g1 = "1234567890";
34     std::string g2 = "1234567891";
35     T s1(g1.begin(), g1.end());
36     T s2(g2.begin(), g2.end());
37     assert(h(s1) != h(s2));
38 }
39 
main()40 int main()
41 {
42     test<std::string>();
43 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
44     test<std::u16string>();
45     test<std::u32string>();
46 #endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
47     test<std::wstring>();
48 }
49