BOOST：使用local_date_time 计算当前时间戳

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> #include <boost/date_time/local_time/local_time.hpp> using namespace std; using namespace boost::gregorian; using namespace boost::local_time; using namespace boost::posix_time; int main() { tz_database tz_db; try { /* *加载时区数据库 */ tz_db.load_from_file("/usr/local/boost_1_42_0/libs/date_time/data/date_time_zonespec.csv"); } catch(data_not_accessible dna) { std::cerr << "Error with time zone data file: " << dna.what() << std::endl; exit(EXIT_FAILURE); } catch(bad_field_count bfc) { std::cerr << "Error with time zone data file: " << bfc.what() << std::endl; exit(EXIT_FAILURE); } /* *由于没有找到北京，我们暂时指向重庆 */ time_zone_ptr time_zone = tz_db.time_zone_from_region("Asia/Chongqing"); const time_t tt = time(NULL); tm* pLocalTime = localtime(&tt); date record_date(pLocalTime->tm_year+1900,pLocalTime->tm_mon+1,pLocalTime->tm_mday); time_duration record_time(pLocalTime->tm_hour,pLocalTime->tm_min,pLocalTime->tm_sec); /* *本地当前时间 */ local_date_time time_t_now(record_date, record_time, time_zone, local_date_time::NOT_DATE_TIME_ON_ERROR); std::cout << "localtime:[" << time_t_now << "]" << std::endl; /* *纪元时间 */ ptime time_t_begin(date(1970,1,1)); time_duration timestamp = time_t_now.utc_time() - time_t_begin; 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 * understood to be in the passed tz. The DST flag is calculated * according to the specified rule. */ local_date_time_base(date_type d, time_duration_type td, boost::shared_ptr<tz_type> tz, DST_CALC_OPTIONS calc_option) : // dummy value - time_ is set in constructor code date_time::base_time<utc_time_type,time_system_type>(utc_time_type(d,td)), zone_(tz)  

 

 

运行结果：

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