Qt QDateTime 纳秒（1970 年 1 月 1 日起）

发布于 2024-09-07 08:30:39 字数 880 浏览 5 评论 0原文

我即将从一个文件中读取数据，该文件存储了 1970 年 1 月 1 日起的纳秒时间。我的问题是我想将其读取到 QDateTime 对象，但它根本无法按照我想要的方式工作，并且 Qt 文档也没有帮助我。

注意：毫秒光栅足以满足我的目的这是我目前的方法：

void setDateTime(qint64 &ns)
{
    _datetime.setDate(QDate(1970,1,1));
    _datetime.setTime(QTime(0,0,0,0));
    ns /= 1000; //ns are now ms
    qDebug() << "| ms = " << ns;
    qDebug() << "| days = " << static_cast<int>(ns%(60*60*24*1E6));
    _datetime.addDays( static_cast<int>(ns%(60*60*24*1000)) );
    _datetime.addMSecs( ns - ((ns/(60*60*24*1000))*60*60*24*1E6) );
    qDebug() << "| dt = " << _datetime;
}

结果总是

 | dt =  QDateTime("Thu Jan 1 00:00:00 1970")

肯定是错误的，

有人能告诉我我的缺陷在哪里吗？感谢您的任何提示和帮助。

编辑： setTime_t 显然是我想要的（除了毫秒分辨率），并且按预期工作，但我真的很好奇为什么上述方法不起作用。

编辑将 hack-away 错误从 1E6 乘法更改为 1E6

原文

I am about to read data From a File which has stored it's time in nanoseconds from 1/1/1970. My problem is I want to read it to a QDateTime object, but it simply does not work as I want it to and the Qt Documentation did not help me either.

Note: milliseconds raster is enough for my purposes
Here my current approach:

void setDateTime(qint64 &ns)
{
    _datetime.setDate(QDate(1970,1,1));
    _datetime.setTime(QTime(0,0,0,0));
    ns /= 1000; //ns are now ms
    qDebug() << "| ms = " << ns;
    qDebug() << "| days = " << static_cast<int>(ns%(60*60*24*1E6));
    _datetime.addDays( static_cast<int>(ns%(60*60*24*1000)) );
    _datetime.addMSecs( ns - ((ns/(60*60*24*1000))*60*60*24*1E6) );
    qDebug() << "| dt = " << _datetime;
}

the result is always

 | dt =  QDateTime("Thu Jan 1 00:00:00 1970")

which is surely wrong

Can anybody tell where my flaw is? Thanks for any tips and help.

Edit: setTime_t is obviously what I wanted (except for msec resolution), and that works as expected, but I am really curious why the above approach does not work.

Edit changed hack-away bug from 1E6 multiplicative to 1E6

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