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## Class template null_dst_rules

boost::date_time::null_dst_rules — Used for local time adjustments in places that don't use dst.

## Synopsis

    // In header: <boost/date_time/dst_rules.hpp>

    template<typename date_type_, typename time_duration_type_>
    class null_dst_rules {
    public:
      // types
      typedef time_duration_type_ time_duration_type;
      typedef date_type_          date_type;

      // public static functions
      static time_is_dst_result
      local_is_dst(const date_type &, const time_duration_type &) ;
      static time_is_dst_result
      utc_is_dst(const date_type &, const time_duration_type &) ;
      static bool is_dst_boundary_day(date_type) ;
      static time_duration_type dst_offset() ;
    };

## Description

### `null_dst_rules` public static functions

1.     static time_is_dst_result
       local_is_dst(const date_type &, const time_duration_type &) ;

   Calculates if the given local time is dst or not.

2.     static time_is_dst_result
       utc_is_dst(const date_type &, const time_duration_type &) ;

   Calculates if the given utc time is in dst.

3.     static bool is_dst_boundary_day(date_type d) ;

4.     static time_duration_type dst_offset() ;