1//
2// detail/chrono.hpp
3// ~~~~~~~~~~~~~~~~~
4//
5// Copyright (c) 2003-2024 Christopher M. Kohlhoff (chris at kohlhoff dot com)
6//
7// Distributed under the Boost Software License, Version 1.0. (See accompanying
8// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
9//
10
11#ifndef BOOST_ASIO_DETAIL_CHRONO_HPP
12#define BOOST_ASIO_DETAIL_CHRONO_HPP
13
14#if defined(_MSC_VER) && (_MSC_VER >= 1200)
15# pragma once
16#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
17
18#include <boost/asio/detail/config.hpp>
19#include <chrono>
20
21namespace boost {
22namespace asio {
23namespace chrono {
24
25using std::chrono::duration;
26using std::chrono::time_point;
27using std::chrono::duration_cast;
28using std::chrono::nanoseconds;
29using std::chrono::microseconds;
30using std::chrono::milliseconds;
31using std::chrono::seconds;
32using std::chrono::minutes;
33using std::chrono::hours;
34using std::chrono::time_point_cast;
35#if defined(BOOST_ASIO_HAS_STD_CHRONO_MONOTONIC_CLOCK)
36typedef std::chrono::monotonic_clock steady_clock;
37#else // defined(BOOST_ASIO_HAS_STD_CHRONO_MONOTONIC_CLOCK)
38using std::chrono::steady_clock;
39#endif // defined(BOOST_ASIO_HAS_STD_CHRONO_MONOTONIC_CLOCK)
40using std::chrono::system_clock;
41using std::chrono::high_resolution_clock;
42
43} // namespace chrono
44} // namespace asio
45} // namespace boost
46
47#endif // BOOST_ASIO_DETAIL_CHRONO_HPP
48

source code of boost/libs/asio/include/boost/asio/detail/chrono.hpp