Question

我在我的系统上运行find /usr/share/zoneinfo/ -type f -exec file {} \; |grep -v 'no leap'，并且每个时区文件都说它没有闰秒。闰秒存储在mac OS X的任何地方，我可以以健壮的方式获得吗？我正在编写一个需要闰秒的库，所以我宁愿不通过网络连接，尽管可以接受某种系统调用。

Answer 1

在macOS上的IANA数据库中没有存储闰秒信息：/ usr / share / zoneinfo

如果您愿意使用第三方C ++ 11库，Howard Hinnant's time zone library为您提供处理闰秒的全部功能。这确实需要下载IANA数据库。但您可以将此库配置为自动下载，也可以手动下载，库将访问该库。

文档中有这个例子：

#include "tz.h"
#include <iostream>

int
main()
{
    using namespace date;
    using namespace std::chrono_literals;
    auto start = to_utc_time(sys_days{2015_y/jul/1} - 500ms);
    auto end = start + 2s;
    for (auto utc = start; utc < end; utc += 100ms)
    {
        auto sys = to_sys_time(utc);
        auto tai = to_tai_time(utc);
        auto gps = to_gps_time(utc);
        std::cout << format("%F %T SYS  ==  ", sys)
                  << format("%F %T %Z  ==  ", utc)
                  << format("%F %T %Z  ==  ", tai)
                  << format("%F %T %Z\n", gps);
    }
}

此示例迭代2015年6月闰秒插入附近的时间，比较系统时间，UTC，TAI和GPS时钟标准：

2015-06-30 23:59:59.500 SYS  ==  2015-06-30 23:59:59.500 UTC  ==  2015-07-01 00:00:34.500 TAI  ==  2015-07-01 00:00:15.500 GPS
2015-06-30 23:59:59.600 SYS  ==  2015-06-30 23:59:59.600 UTC  ==  2015-07-01 00:00:34.600 TAI  ==  2015-07-01 00:00:15.600 GPS
2015-06-30 23:59:59.700 SYS  ==  2015-06-30 23:59:59.700 UTC  ==  2015-07-01 00:00:34.700 TAI  ==  2015-07-01 00:00:15.700 GPS
2015-06-30 23:59:59.800 SYS  ==  2015-06-30 23:59:59.800 UTC  ==  2015-07-01 00:00:34.800 TAI  ==  2015-07-01 00:00:15.800 GPS
2015-06-30 23:59:59.900 SYS  ==  2015-06-30 23:59:59.900 UTC  ==  2015-07-01 00:00:34.900 TAI  ==  2015-07-01 00:00:15.900 GPS
2015-06-30 23:59:59.999 SYS  ==  2015-06-30 23:59:60.000 UTC  ==  2015-07-01 00:00:35.000 TAI  ==  2015-07-01 00:00:16.000 GPS
2015-06-30 23:59:59.999 SYS  ==  2015-06-30 23:59:60.100 UTC  ==  2015-07-01 00:00:35.100 TAI  ==  2015-07-01 00:00:16.100 GPS
2015-06-30 23:59:59.999 SYS  ==  2015-06-30 23:59:60.200 UTC  ==  2015-07-01 00:00:35.200 TAI  ==  2015-07-01 00:00:16.200 GPS
2015-06-30 23:59:59.999 SYS  ==  2015-06-30 23:59:60.300 UTC  ==  2015-07-01 00:00:35.300 TAI  ==  2015-07-01 00:00:16.300 GPS
2015-06-30 23:59:59.999 SYS  ==  2015-06-30 23:59:60.400 UTC  ==  2015-07-01 00:00:35.400 TAI  ==  2015-07-01 00:00:16.400 GPS
2015-06-30 23:59:59.999 SYS  ==  2015-06-30 23:59:60.500 UTC  ==  2015-07-01 00:00:35.500 TAI  ==  2015-07-01 00:00:16.500 GPS
2015-06-30 23:59:59.999 SYS  ==  2015-06-30 23:59:60.600 UTC  ==  2015-07-01 00:00:35.600 TAI  ==  2015-07-01 00:00:16.600 GPS
2015-06-30 23:59:59.999 SYS  ==  2015-06-30 23:59:60.700 UTC  ==  2015-07-01 00:00:35.700 TAI  ==  2015-07-01 00:00:16.700 GPS
2015-06-30 23:59:59.999 SYS  ==  2015-06-30 23:59:60.800 UTC  ==  2015-07-01 00:00:35.800 TAI  ==  2015-07-01 00:00:16.800 GPS
2015-06-30 23:59:59.999 SYS  ==  2015-06-30 23:59:60.900 UTC  ==  2015-07-01 00:00:35.900 TAI  ==  2015-07-01 00:00:16.900 GPS
2015-07-01 00:00:00.000 SYS  ==  2015-07-01 00:00:00.000 UTC  ==  2015-07-01 00:00:36.000 TAI  ==  2015-07-01 00:00:17.000 GPS
2015-07-01 00:00:00.100 SYS  ==  2015-07-01 00:00:00.100 UTC  ==  2015-07-01 00:00:36.100 TAI  ==  2015-07-01 00:00:17.100 GPS
2015-07-01 00:00:00.200 SYS  ==  2015-07-01 00:00:00.200 UTC  ==  2015-07-01 00:00:36.200 TAI  ==  2015-07-01 00:00:17.200 GPS
2015-07-01 00:00:00.300 SYS  ==  2015-07-01 00:00:00.300 UTC  ==  2015-07-01 00:00:36.300 TAI  ==  2015-07-01 00:00:17.300 GPS
2015-07-01 00:00:00.400 SYS  ==  2015-07-01 00:00:00.400 UTC  ==  2015-07-01 00:00:36.400 TAI  ==  2015-07-01 00:00:17.400 GPS

闰秒是否存储在Mac OS X上的任何位置？

1 个答案: