TimeZone

 configTime(0, 0, "time.google.com", "time.windows.com", "pool.ntp.org");

 // https://github.com/nayarsystems/posix_tz_db/blob/master/zones.json
 setenv("TZ", "CET-1CEST,M3.5.0,M10.5.0/3", 1);
 tzset();