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 <class T>
12 // struct hash
13 //     : public unary_function<T, size_t>
14 // {
15 //     size_t operator()(T val) const;
16 // };
17 
18 #include <system_error>
19 #include <cassert>
20 #include <type_traits>
21 
22 #include "test_macros.h"
23 
24 void
25 test(int i)
26 {
27     typedef std::error_code T;
28     typedef std::hash<T> H;
29     static_assert((std::is_same<H::argument_type, T>::value), "" );
30     static_assert((std::is_same<H::result_type, std::size_t>::value), "" );
31     ASSERT_NOEXCEPT(H()(T()));
32     H h;
33     T ec(i, std::system_category());
34     const std::size_t result = h(ec);
35     LIBCPP_ASSERT(result == static_cast<std::size_t>(i));
36     ((void)result); // Prevent unused warning
37 }
38 
39 int main(int, char**)
40 {
41     test(0);
42     test(2);
43     test(10);
44 
45   return 0;
46 }
47