学步园

在工作中，我们经常使用时间戳，来标示些特性，昨天也正好有个同事问我，所以想起用这个办法。

原理：取得现在时间的utc - 纪元时间。

#include <iostream><br /> #include <boost/date_time/local_time/local_time.hpp><br /> using namespace std;<br /> using namespace boost::gregorian;<br /> using namespace boost::local_time;<br /> using namespace boost::posix_time;<br /> int main()<br /> {<br /> tz_database tz_db;<br /> try<br /> {<br /> /*<br /> *加载时区数据库<br /> */<br /> tz_db.load_from_file("/usr/local/boost_1_42_0/libs/date_time/data/date_time_zonespec.csv");<br /> }<br /> catch(data_not_accessible dna)<br /> {<br /> std::cerr << "Error with time zone data file: " << dna.what() << std::endl;<br /> exit(EXIT_FAILURE);<br /> }<br /> catch(bad_field_count bfc)<br /> {<br /> std::cerr << "Error with time zone data file: " << bfc.what() << std::endl;<br /> exit(EXIT_FAILURE);<br /> }<br /> /*<br /> *由于没有找到北京，我们暂时指向重庆<br /> */<br /> time_zone_ptr time_zone = tz_db.time_zone_from_region("Asia/Chongqing");<br /> const time_t tt = time(NULL);<br /> tm* pLocalTime = localtime(&tt);<br /> date record_date(pLocalTime->tm_year+1900,pLocalTime->tm_mon+1,pLocalTime->tm_mday);<br /> time_duration record_time(pLocalTime->tm_hour,pLocalTime->tm_min,pLocalTime->tm_sec);<br /> /*<br /> *本地当前时间<br /> */<br /> local_date_time time_t_now(record_date,<br /> record_time,<br /> time_zone,<br /> local_date_time::NOT_DATE_TIME_ON_ERROR);<br /> std::cout << "localtime:[" << time_t_now << "]" << std::endl;<br /> /*<br /> *纪元时间<br /> */<br /> ptime time_t_begin(date(1970,1,1));<br /> time_duration timestamp = time_t_now.utc_time() - time_t_begin;<br /> cout << "timestamp:[" << timestamp.total_seconds() << "]" << endl ;

这是构造函数的声明,所在<boost/date_time/local_time/local_date_time.hpp>中

/*! This constructs a local time -- the passed time information<br /> * understood to be in the passed tz. The DST flag is calculated<br /> * according to the specified rule.<br /> */<br /> local_date_time_base(date_type d,<br /> time_duration_type td,<br /> boost::shared_ptr<tz_type> tz,<br /> DST_CALC_OPTIONS calc_option) :<br /> // dummy value - time_ is set in constructor code<br /> date_time::base_time<utc_time_type,time_system_type>(utc_time_type(d,td)),<br /> zone_(tz)<br />  

运行结果：

[root@localhost bin]# ./date<br /> localtime:[2010-Jul-08 09:32:18 CST]<br /> timestamp:[1278552738]<br />