test/std/utilities/time/time.point/time.point.nonmember/op_-duration.pass.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <chrono>

// time_point

// template <class Clock, class Duration1, class Rep2, class Period2>
//   time_point<Clock, typename common_type<Duration1, duration<Rep2, Period2>>::type>
//   operator-(const time_point<Clock, Duration1>& lhs, const duration<Rep2, Period2>& rhs);

#include <chrono>
#include <cassert>

#include "test_macros.h"

template <class D>
void test2739()  // LWG2739
{
    typedef std::chrono::time_point<std::chrono::system_clock> TimePoint;
    typedef std::chrono::duration<D> Dur;
    const Dur d(5);
    TimePoint t0 = std::chrono::system_clock::from_time_t(200);
    TimePoint t1 = t0 - d;
    assert(t1 < t0);
}

int main()
{
    typedef std::chrono::system_clock Clock;
    typedef std::chrono::milliseconds Duration1;
    typedef std::chrono::microseconds Duration2;
    {
    std::chrono::time_point<Clock, Duration1> t1(Duration1(3));
    std::chrono::time_point<Clock, Duration2> t2 = t1 - Duration2(5);
    assert(t2.time_since_epoch() == Duration2(2995));
    }
#if TEST_STD_VER > 11
    {
    constexpr std::chrono::time_point<Clock, Duration1> t1(Duration1(3));
    constexpr std::chrono::time_point<Clock, Duration2> t2 = t1 - Duration2(5);
    static_assert(t2.time_since_epoch() == Duration2(2995), "");
    }
#endif
    test2739<int32_t>();
    test2739<uint32_t>();
}