Wording for GB 50

Proposed Wording

1. Modify the synopsis of 20.17.5 [time.duration]:

   template <class Rep, class Period = ratio<1>>
   class duration {
   public:
       using rep    = Rep;
       using period = Period;
   private:
       rep rep_; // exposition only public:
   public:
       // 20.17.5.1, construct/copy/destroy:
       constexpr duration() = default;
       template <class Rep2>
           constexpr explicit duration(const Rep2& r);
       template <class Rep2, class Period2>
           constexpr duration(const duration<Rep2, Period2>& d);
       ~duration() = default;
       duration(const duration&) = default;
       duration& operator=(const duration&) = default;
   
       // 20.17.5.2, observer:
       constexpr rep count() const;
   
       // 20.17.5.3, arithmetic:
       constexpr duration operator+() const;
       constexpr duration operator-() const;
       constexpr duration& operator++();
       constexpr duration operator++(int);
       constexpr duration& operator--();
       constexpr duration operator--(int);
   
       constexpr duration& operator+=(const duration& d);
       constexpr duration& operator-=(const duration& d);
   
       constexpr duration& operator*=(const rep& rhs);
       constexpr duration& operator/=(const rep& rhs);
       constexpr duration& operator%=(const rep& rhs);
       constexpr duration& operator%=(const duration& rhs);
   
       // 20.17.5.4, special values:
       static constexpr duration zero();
       static constexpr duration min();
       static constexpr duration max();
   };
   

2. Modify 20.17.5.3 [time.duration.arithmetic]:

   ...
   constexpr duration& operator++();
   ...
   constexpr duration operator++(int);
   ...
   constexpr duration& operator--();
   ...
   constexpr duration operator--(int);
   ...
   constexpr duration& operator+=(const duration& d);
   ...
   constexpr duration& operator-=(const duration& d);
   ...
   constexpr duration& operator*=(const rep& rhs);
   ...
   constexpr duration& operator/=(const rep& rhs);
   ...
   constexpr duration& operator%=(const rep& rhs);
   ...
   constexpr duration& operator%=(const duration& rhs);
   ...
   

3. Modify the synopsis of 20.17.6 [time.point]:

   template <class Clock, class Duration = typename Clock::duration>
   class time_point {
   public:
       using clock    = Clock;
       using duration = Duration;
       using rep      = typename duration::rep;
       using period   = typename duration::period;
   private:
       duration d_;  // exposition only
   public:
       // 20.17.6.1, construct:
       constexpr time_point(); // has value epoch
       constexpr explicit time_point(const duration& d);  // same as time_point() + d
       template <class Duration2>
           constexpr time_point(const time_point<clock, Duration2>& t);
   
       // 20.17.6.2, observer:
       constexpr duration time_since_epoch() const;
   
       // 20.17.6.3, arithmetic:
       constexpr time_point& operator+=(const duration& d);
       constexpr time_point& operator-=(const duration& d);
   
       // 20.17.6.4, special values:
       static constexpr time_point min();
       static constexpr time_point max();
   };
   

4. Modify 20.17.6.3 [time.point.arithmetic]:

   ...
   constexpr time_point& operator+=(const duration& d);
   ...
   constexpr time_point& operator-=(const duration& d);
   ...