Boost - 使用时间戳记格式化次精度时间 [英] Boost - Formatting sub second precision time with a time stamp

问题描述

我需要以毫秒的精度获得格式正确的时间戳（略微修改ISO 8601）。

I need to get a nicely formatted timestamp (slightly modified ISO 8601) with millisecond precision.

示例日期如下所示： 2011-09-28 13：11：15.237-08：00

格式化也应该能够覆盖。

And example date would look like this: 2011-09-28 13:11:15.237-08:00
The formatting should be able to be overwridden as well.

我一直在玩 boost :: posix_time :: microsec_clock :: local_time（） 和 boost :: posix_time :: time_facet ，除非它

由于posix时间不包含时区信息，这是不可能的（我猜猜）

I've been playing around with boost::posix_time::microsec_clock::local_time() and boost::posix_time::time_facet which works just fine except when it comes to timestamps.
Since posix time doesn't contain time zone information this is just not possible (I'm guessing)

因此，还有其他任何我可以使用的毫秒精度包含时区信息，或者我可以使 time_facet 与时区一起工作吗？

So, is there anything else I could use that has millisecond precision that contains timezone information or can I make the time_facet work with timezones?

也许我应该总是使用UTC？

Maybe I should always use UTC?

谢谢

推荐答案

看看boost :: local_time :: local_date_time类。您可以指定时区，并使用本地微秒时钟来初始化它

Have a look at the boost::local_time::local_date_time class. You can specify a time zone and use the local microsecond clock to initialize it like

boost::local_time::local_date_time  my_ldt(boost::local_time::local_microsec_clock::local_time(new boost::local_time::posix_time_zone("EST-5EDT,M4.1.0,M10.5.0")));

您应该能够使用facet格式化为字符串。

You should then be able to use the facets to format to a string.

编辑：完整示例：

#include <iostream>
#include <iomanip>
#include <string>
#include <sstream>

#include <boost/date_time/local_time/local_time.hpp>

int main(void)
{
    boost::posix_time::ptime  now = boost::posix_time::second_clock::local_time();
    boost::posix_time::ptime  utc = boost::posix_time::second_clock::universal_time();

    boost::posix_time::time_duration tz_offset = (now - utc);

    std::stringstream   ss;
    boost::local_time::local_time_facet* output_facet = new boost::local_time::local_time_facet();
    ss.imbue(std::locale(std::locale::classic(), output_facet));

    output_facet->format("%H:%M:%S");
    ss.str("");
    ss << tz_offset;

    boost::local_time::time_zone_ptr    zone(new boost::local_time::posix_time_zone(ss.str().c_str()));
    boost::local_time::local_date_time  ldt = boost::local_time::local_microsec_clock::local_time(zone);
    boost::local_time::local_time_facet* output_facet = new boost::local_time::local_time_facet();
    ss.imbue(std::locale(std::locale::classic(), output_facet));
    output_facet->format("%Y-%m-%d %H:%M:%S%f%Q");
    ss.str("");
    ss << ldt;
    std::cout << ss.str() << std::endl; // "2004-02-29 12:34:56.000789-05:00"

    std::cout << "Press return to exit" << std::endl;
    std::string wait_for_line;
    std::getline(std::cin, wait_for_line);

    return (0);
}

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