如何在 C++ 中构建 ISO 8601 日期时间?

问题描述

我正在使用 Azure REST API，他们正在使用它来创建表存储的请求正文:

I'm working with the Azure REST API and they are using this to create the request body for table storage:

DateTime.UtcNow.ToString("o")

产生:

2012-03-02T04:07:34.0218628Z

2012-03-02T04:07:34.0218628Z

它被称为往返"，显然它是一个 ISO 标准(参见 http://en.wikipedia.org/wiki/ISO_8601) 但我不知道如何在阅读 wiki 文章后复制它.

It is called "round-trip" and apparently it's an ISO standard (see http://en.wikipedia.org/wiki/ISO_8601) but I have no idea how to replicate it after reading the wiki article.

有谁知道 Boost 是否支持这个，或者可能 Qt?

Does anyone know if Boost has support for this, or possibly Qt?

推荐答案

如果到最接近秒的时间足够精确，可以使用strftime:

If the time to the nearest second is precise enough, you can use strftime:

#include <ctime>
#include <iostream>

int main() {
    time_t now;
    time(&now);
    char buf[sizeof "2011-10-08T07:07:09Z"];
    strftime(buf, sizeof buf, "%FT%TZ", gmtime(&now));
    // this will work too, if your compiler doesn't support %F or %T:
    //strftime(buf, sizeof buf, "%Y-%m-%dT%H:%M:%SZ", gmtime(&now));
    std::cout << buf << "
";
}

如果您需要更高的精度，可以使用 Boost:

If you need more precision, you can use Boost:

#include <iostream>
#include <boost/date_time/posix_time/posix_time.hpp>

int main() {
    using namespace boost::posix_time;
    ptime t = microsec_clock::universal_time();
    std::cout << to_iso_extended_string(t) << "Z
";
}

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