Re: [Boost-users] convert separate year, month, day, hour, minute, secs, ms to milliseconds since epoch

11 Mar 2019


      On Sun, 3 Mar 2019 12:45:17 -0800
Victor Yankee via Boost-users  wrote:
...
I am using C++14 and boost 1.64.0 (could move to newest boost), and
need to convert date and time pieces to a single value for
milliseconds since the epoch. This is what I have:
int64_t msSinceEpoch(int year,int month,int day,int hour,int
minute,int second,int ms)
            {
            struct std::tm t;
            t.tm_sec    = second;
            t.tm_min    = minute;
            t.tm_hour   = hour;
            t.tm_mday   = day;
            t.tm_mon    = month-1;
            t.tm_year   = year-1900;
            t.tm_isdst  = 0;
            return (1000* timegm(&t))+ms; // is timegm cross-platform?
            }
Is there a better way?
time_tsec_since_epoch(int year, int month, int day,
                    int hour, int minute, int second) 
{ 
  static const boost::posix_time::ptime
epoch(boost::gregorian::date(1970,1,1));

  boost::posix_time::ptime pt(
      boost::gregorian::date(year, month, day),
      boost::posix_time::time_duration(hour, minute, second)
  );

  boost::posix_time::time_duration since_epoch = pt - epoch;
  return since_epoch.total_seconds(); 
}


-- 
Best regards, Sergey Spiridonov