ceph/src/boost/libs/date_time/example/local_time/seconds_since_epoch.cpp

   1 /* This example demonstrates the use of the time zone database and
   2  * local time to calculate the number of seconds since the UTC
   3  * time_t epoch 1970-01-01 00:00:00.  Note that the selected timezone
   4  * could be any timezone supported in the time zone database file which
   5  * can be modified and updated as needed by the user.
   6  *
   7  * To solve this problem the following steps are required:
   8  * 1) Get a timezone from the tz database for the local time
   9  * 2) Construct a local time using the timezone
  10  * 3) Construct a posix_time::ptime for the time_t epoch time
  11  * 4) Convert the local_time to utc and subtract the epoch time
  12  *
  13  */
  14
  15 #include "boost/date_time/local_time/local_time.hpp"
  16 #include <iostream>
  17
  18 int main()
  19 {
  20   using namespace boost::gregorian;
  21   using namespace boost::local_time;
  22   using namespace boost::posix_time;
  23
  24   tz_database tz_db;
  25   try {
  26     tz_db.load_from_file("../data/date_time_zonespec.csv");
  27   }catch(const data_not_accessible& dna) {
  28     std::cerr << "Error with time zone data file: " << dna.what() << std::endl;
  29     exit(EXIT_FAILURE);
  30   }catch(const bad_field_count& bfc) {
  31     std::cerr << "Error with time zone data file: " << bfc.what() << std::endl;
  32     exit(EXIT_FAILURE);
  33   }
  34
  35   time_zone_ptr nyc_tz = tz_db.time_zone_from_region("America/New_York");
  36   date in_date(2004,10,04);
  37   time_duration td(12,14,32);
  38   // construct with local time value
  39   // create not-a-date-time if invalid (eg: in dst transition)
  40   local_date_time nyc_time(in_date,
  41                            td,
  42                            nyc_tz,
  43                            local_date_time::NOT_DATE_TIME_ON_ERROR);
  44
  45   std::cout << nyc_time << std::endl;
  46
  47   ptime time_t_epoch(date(1970,1,1));
  48   std::cout << time_t_epoch << std::endl;
  49
  50   // first convert nyc_time to utc via the utc_time()
  51   // call and subtract the ptime.
  52   time_duration diff = nyc_time.utc_time() - time_t_epoch;
  53
  54   //Expected 1096906472
  55   std::cout << "Seconds diff: " << diff.total_seconds() << std::endl;
  56
  57 }
  58
  59
  60 /*  Copyright 2005: CrystalClear Software, Inc
  61  *  http://www.crystalclearsoftware.com
  62  *
  63  *  Subject to the Boost Software License, Version 1.0.
  64  * (See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
  65  */