1// min_time_point.cpp ----------------------------------------------------------//
2
3// Copyright 2008 Howard Hinnant
4// Copyright 2008 Beman Dawes
5// Copyright 2009 Vicente J. Botet Escriba
6
7// Distributed under the Boost Software License, Version 1.0.
8// See http://www.boost.org/LICENSE_1_0.txt
9
10/*
11This code was extracted by Vicente J. Botet Escriba from Beman Dawes time2_demo.cpp which
12was derived by Beman Dawes from Howard Hinnant's time2_demo prototype.
13Many thanks to Howard for making his code available under the Boost license.
14The original code was modified to conform to Boost conventions and to section
1520.9 Time utilities [time] of the C++ committee's working paper N2798.
16See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2798.pdf.
17
18time2_demo contained this comment:
19
20 Much thanks to Andrei Alexandrescu,
21 Walter Brown,
22 Peter Dimov,
23 Jeff Garland,
24 Terry Golubiewski,
25 Daniel Krugler,
26 Anthony Williams.
27*/
28
29#include <boost/chrono/typeof/boost/chrono/chrono.hpp>
30#include <boost/type_traits.hpp>
31
32#include <iostream>
33
34using namespace boost::chrono;
35
36template <class Rep, class Period>
37void print_duration(std::ostream& os, duration<Rep, Period> d)
38{
39 os << d.count() << " * " << Period::num << '/' << Period::den << " seconds\n";
40}
41
42namespace my_ns {
43// Example min utility: returns the earliest time_point
44// Being able to *easily* write this function is a major feature!
45template <class Clock, class Duration1, class Duration2>
46inline
47typename boost::common_type<time_point<Clock, Duration1>,
48 time_point<Clock, Duration2> >::type
49min BOOST_PREVENT_MACRO_SUBSTITUTION (time_point<Clock, Duration1> t1, time_point<Clock, Duration2> t2)
50{
51 return t2 < t1 ? t2 : t1;
52}
53}
54void test_min()
55{
56#if 1
57 typedef time_point<system_clock,
58 boost::common_type<system_clock::duration, seconds>::type> T1;
59 typedef time_point<system_clock,
60 boost::common_type<system_clock::duration, nanoseconds>::type> T2;
61 typedef boost::common_type<T1, T2>::type T3;
62 /*auto*/ T1 t1 = system_clock::now() + seconds(3);
63 /*auto*/ T2 t2 = system_clock::now() + nanoseconds(3);
64 /*auto*/ T3 t3 = (my_ns::min)(t1, t2);
65#else
66 BOOST_AUTO(t1, system_clock::now() + seconds(3));
67 BOOST_AUTO(t2, system_clock::now() + nanoseconds(3));
68 BOOST_AUTO(t3, (min)(t1, t2));
69#endif
70 print_duration(os&: std::cout, d: t1 - t3);
71 print_duration(os&: std::cout, d: t2 - t3);
72}
73
74int main()
75{
76 test_min();
77 return 0;
78}
79
80

source code of boost/libs/chrono/example/min_time_point.cpp