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

On 4/03/2019 09:45, Victor Yankee 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?             }

timegm is not cross platform. mktime is, but uses local time instead of UTC.

Is there a better way? Could not figure out how to use boost::chrono :( Something else?

Boost.Chrono is for time intervals, not dates. Boost.DateTime, however, has the ptime class which will solve this for you.