[PATCH] Extend time parsing to before 1970

[Thiago Macieira]

On quinta-feira, 28 de abril de 2016 16:17:15 PDT Linus Torvalds wrote:
> That's very odd. It's *especially* odd since I'm doing this on x86-64,
> which natively has a 64-bit signed time_t, and all the normal date
> handling functions should just work fine. But Qt seems to have explicitly
> screwed up here.
> 
> Thiago?

Historical raisins... In order to support multiple operating systems with 
dubious definitions of time_t (signed, unsigned, 32-bit, 64-bit), the API was 
crystallised on unsigned some time in the past. I'd advise against using this 
function that you found:

> Looking at
> 
>    http://doc.qt.io/qt-5/qdatetime.html#fromTime_t-1
> 
> it just looks like "QDateTime::fromTime_t()" is completely and utterly
> broken.

Yep. But we have to carry it for compatibility.

> I guess we could replace all those with
> 
>    QDateTime::fromMSecsSinceEpoch(when*1000, Qt::UTC)
> 
> or something. I have *not* tested whether that works.

That's what I recommend. The range is ± ~292 million years . It's also 64-bit 
even on 32-bit systems with time_t definitions unsafe after 2038.

Which means you've got +1 from me on your second patch.

-- 
Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
   Software Architect - Intel Open Source Technology Center