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<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE library PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN"
"../../../tools/boostbook/dtd/boostbook.dtd">
<!-- Copyright (c) 2001-2005 CrystalClear Software, Inc.
Subject to the Boost Software License, Version 1.0.
(See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
-->
<section id="date_time.examples.simple_time_zone">
<title>Simple Time Zones</title>
<para>
Example usage of custom_time_zone as well as posix_time_zone.
</para>
<programlisting>
<![CDATA[
/* A simple example for using a custom_time_zone and a posix_time_zone.
*/
#include "boost/date_time/local_time/local_time.hpp"
#include <iostream>
int
main()
{
using namespace boost;
using namespace local_time;
using namespace gregorian;
using posix_time::time_duration;
/***** custom_time_zone *****/
// create the dependent objects for a custom_time_zone
time_zone_names tzn("Eastern Standard Time", "EST",
"Eastern Daylight Time", "EDT");
time_duration utc_offset(-5,0,0);
dst_adjustment_offsets adj_offsets(time_duration(1,0,0),
time_duration(2,0,0),
time_duration(2,0,0));
// rules for this zone are:
// start on first Sunday of April at 2 am
// end on last Sunday of October at 2 am
// so we use a first_last_dst_rule
first_day_of_the_week_in_month start_rule(Sunday, Apr);
last_day_of_the_week_in_month end_rule(Sunday, Oct);
shared_ptr<dst_calc_rule> nyc_rules(new first_last_dst_rule(start_rule,
end_rule));
// create more dependent objects for a non-dst custom_time_zone
time_zone_names tzn2("Mountain Standard Time", "MST",
"", ""); // no dst means empty dst strings
time_duration utc_offset2(-7,0,0);
dst_adjustment_offsets adj_offsets2(time_duration(0,0,0),
time_duration(0,0,0),
time_duration(0,0,0));
// no dst means we need a null pointer to the rules
shared_ptr<dst_calc_rule> phx_rules;
// create the custom_time_zones
time_zone_ptr nyc_1(new custom_time_zone(tzn, utc_offset,
adj_offsets, nyc_rules));
time_zone_ptr phx_1(new custom_time_zone(tzn2, utc_offset2,
adj_offsets2, phx_rules));
/***** posix_time_zone *****/
// create posix_time_zones that are the duplicates of the
// custom_time_zones created above. See posix_time_zone documentation
// for details on full zone names.
std::string nyc_string, phx_string;
nyc_string = "EST-05:00:00EDT+01:00:00,M4.1.0/02:00:00,M10.5.0/02:00:00";
// nyc_string = "EST-05EDT,M4.1.0,M10.5.0"; // shorter when defaults used
phx_string = "MST-07"; // no-dst
time_zone_ptr nyc_2(new posix_time_zone(nyc_string));
time_zone_ptr phx_2(new posix_time_zone(phx_string));
/***** show the sets are equal *****/
std::cout << "The first zone is in daylight savings from:\n "
<< nyc_1->dst_local_start_time(2004) << " through "
<< nyc_1->dst_local_end_time(2004) << std::endl;
std::cout << "The second zone is in daylight savings from:\n "
<< nyc_2->dst_local_start_time(2004) << " through "
<< nyc_2->dst_local_end_time(2004) << std::endl;
std::cout << "The third zone (no daylight savings):\n "
<< phx_1->std_zone_abbrev() << " and "
<< phx_1->base_utc_offset() << std::endl;
std::cout << "The fourth zone (no daylight savings):\n "
<< phx_2->std_zone_abbrev() << " and "
<< phx_2->base_utc_offset() << std::endl;
return 0;
}
]]>
</programlisting>
</section>
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