使用 C++ 和 Boost 以毫秒为单位获取当前时间

问题描述

在我的线程中(使用 boost::thread)我需要以毫秒或更少的时间检索当前时间并转换为毫秒:

In my thread (using boost::thread) I need to retrieve the current time in ms or less and to convert into ms:

实际上，在这里阅读我发现了这一点:

Actually, reading here I've found this:

tick = boost::posix_time::second_clock::local_time();
now  = boost::posix_time::second_clock::local_time();

并且似乎有效，但是在我需要现在的毫秒值之后...

And seems to work, but after I need to have a long value of the milliseconds of the now...

我该怎么做?

推荐答案

您可以使用 boost::posix_time::time_duration 获取时间范围.例如像这样

You can use boost::posix_time::time_duration to get the time range. E.g like this

boost::posix_time::time_duration diff = tick - now;
diff.total_milliseconds();

为了获得更高的分辨率，您可以更改正在使用的时钟.例如对于 boost::posix_time::microsec_clock，尽管这可能取决于操作系统.例如，在 Windows 上，boost::posix_time::microsecond_clock 具有毫秒分辨率，而不是微秒.

And to get a higher resolution you can change the clock you are using. For example to the boost::posix_time::microsec_clock, though this can be OS dependent. On Windows, for example, boost::posix_time::microsecond_clock has milisecond resolution, not microsecond.

一个有点依赖硬件的例子.

An example which is a little dependent on the hardware.

int main(int argc, char* argv[])
{
    boost::posix_time::ptime t1 = boost::posix_time::second_clock::local_time();
    boost::this_thread::sleep(boost::posix_time::millisec(500));
    boost::posix_time::ptime t2 = boost::posix_time::second_clock::local_time();
    boost::posix_time::time_duration diff = t2 - t1;
    std::cout << diff.total_milliseconds() << std::endl;

    boost::posix_time::ptime mst1 = boost::posix_time::microsec_clock::local_time();
    boost::this_thread::sleep(boost::posix_time::millisec(500));
    boost::posix_time::ptime mst2 = boost::posix_time::microsec_clock::local_time();
    boost::posix_time::time_duration msdiff = mst2 - mst1;
    std::cout << msdiff.total_milliseconds() << std::endl;
    return 0;
}

在我的 win7 机器上.第一个输出是 0 或 1000.第二个分辨率.第二个几乎总是 500，因为时钟的分辨率更高.我希望能有所帮助.

On my win7 machine. The first out is either 0 or 1000. Second resolution. The second one is nearly always 500, because of the higher resolution of the clock. I hope that help a little.

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