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 // <map>
10 
11 // class value_compare
12 
13 // bool operator()( const value_type& lhs, const value_type& rhs ) const;
14 
15 #include <map>
16 #include <cassert>
17 #include <string>
18 #include <utility>
19 
20 template <typename Map>
21 struct CallCompMember : Map::value_compare {
22     CallCompMember(const typename Map::value_compare& vc) : Map::value_compare(vc) {}
23 
24     typedef typename Map::value_type value_type;
25     bool operator()(const value_type& value1, const value_type& value2) const {
26         return this->comp(value1.first, value2.first);
27     }
28 };
29 
30 int main(int, char**) {
31     typedef std::map<int, std::string> map_type;
32 
33     map_type m;
34     std::pair<map_type::iterator, bool> p1 = m.insert(map_type::value_type(1, "abc"));
35     std::pair<map_type::iterator, bool> p2 = m.insert(map_type::value_type(2, "abc"));
36 
37     const map_type::value_compare vc = m.value_comp();
38     CallCompMember<map_type> call_comp = m.value_comp();
39 
40     assert(vc(*p1.first, *p2.first));
41     assert(call_comp(*p1.first, *p2.first));
42 
43     assert(!vc(*p2.first, *p1.first));
44     assert(!call_comp(*p2.first, *p1.first));
45 
46     return 0;
47 }
48