boost location-dependent times

淡淡的烟草味﹌ 2021-11-05 12:58 186阅读 0赞

1. local\_date\_time

#include <boost/date_time/local_time/local_time.hpp>
    #include <iostream>
    
    using namespace boost::local_time;
    using namespace boost::posix_time;
    using namespace boost::gregorian;
    
    int main()
    {
      time_zone_ptr tz(new posix_time_zone( "CET+1"));
      ptime pt{date{
         2014, 5, 12}, time_duration{
        12, 0, 0}};
      local_date_time dt{pt, tz};
      std::cout << dt.utc_time() << std::endl;
      std::cout << dt << std::endl;
      std::cout << dt.local_time() << std::endl;
      std::cout << dt.zone_name() << std::endl;
      return 0;
    }

The constructor of boost::local\_time::local\_date\_time expects its first parameter to be an object of type boost::posix\_time::ptime and its second parameter to be an object of type boost::local\_time::time\_zone\_ptr. boost::local\_time::time\_zone\_ptr is a type of definition for boost::shared\_ptr<boost::local\_time::time\_zone>. The type definition is based on boost::local\_time::time\_zone, not boost::local\_time::posix\_time\_zone.

Values used to initialize objects of type boost::posix\_time::ptime and boost::local\_time::local\_date\_time always relate to the UTC time zone by default.

When an object of type `boost::local_time::local_date_time` is written to the standard output stream or a call to the member function `local_time()` is made, the deviation in hours is used to calculate the local time.

2. local\_time\_period

#include <boost/date_time/local_time/local_time.hpp>
    #include <iostream>
    
    using namespace boost::local_time;
    using namespace boost::posix_time;
    using namespace boost::gregorian;
    
    int main()
    {
      time_zone_ptr tz(new posix_time_zone("CET+0"));
    
      ptime pt1(date(2014, 12, 5), time_duration(12, 0, 0));
      local_date_time dt1(pt1, tz);
    
      ptime pt2(date(2014, 12, 5), time_duration(18, 0, 0));
      local_date_time dt2(pt2, tz);
    
      local_time_period tp(dt1, dt2);
    
      std::cout.setf(std::ios::boolalpha);
      std::cout << tp.contains(dt1) << std::endl;
      std::cout << tp.contains(dt2) << std::endl;
      return 0;
    }

The constructor of `boost::local_time::local_time_period` in example above expects two parameters of type `boost::local_time::local_date_time`. As with other types provided for periods, the second parameter, which represents the end time, is not part of the period.

转载于:https://www.cnblogs.com/sssblog/p/11304709.html