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
20template <typename Map>
21struct 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
30int 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(x: map_type::value_type(1, "abc"));
35 std::pair<map_type::iterator, bool> p2 = m.insert(x: 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

source code of libcxx/test/std/containers/associative/map/map.value_compare/invoke.pass.cpp