std.date again

[Carlos Santander]

Walter Bright escribió:
> Carlos Santander wrote:
>> No, I'm saying the UTC result on linux is the correct local result.
> 
> 
> It's hard for me to debug this, because it works in my timezone. Want to 
> give it a try in yours?

I'm completely confused about this whole thing, and I think the problem is 
documentation.

-- On linux (DMD):

If I do toUTCString(getUTCtime()) I correctly get:

Mon, 15 May 2006 17:58:57 UTC

But when I do toTimeString(getUTCtime()) I get:

12:58:57 GMT-0500

So I think toTimeString must be wrong, my logic being that I asked it to return 
the current time as UTC time. But what it returned was the time for my local 
timezone. However, it's never explicitly stated that it should behave that way.

-- On mac (GDC):

It's the same as linux, but the timezone seems to be doing the opposite:

UTC  :Mon, 15 May 2006 18:07:44 UTC
Local:04:07:44 GMT+0500

So it performed an addition instead of a difference.

-- On windows (DMD):

toTimeString(getUTCtime()) returns:

18:13:14 GMT+0000

And toUTCString(getUTCtime()):

Mon, 15 May 2006 18:13:14 UTC

So, on windows, these are ok, I think. At least they behave as I expected them 
to. If I'm right with this, then toTimeString on linux is definitely wrong.

Now, toTimeString(UTCtoLocalTime(getUTCtime())) also returns:

18:13:14 GMT+0000

So, unless toTimeString always prints UTC time (which I don't think it should), 
this is obviously wrong, and the problem has to be in the timezone conversion.

Part of the solution might be here: 
http://www.digitalmars.com/drn-bin/wwwnews?D/20470, but if 
GetTimeZoneInformation() fails, what if instead you use GetLocalTime() to get 
the local time, and since getUTCtime() is ok, then you could use those two 
values to get the timezone (UTCtime - localtime). Does that make sense?

-- Finally....

It's easy, in fact, for you to test it too: change your timezone to different 
parts of the world when debugging this and see what happens. It's really easy to 
do in both linux and windows.

Sorry if that sounded harsh, but I think right now std.date doesn't work in a 
usable way outside your own timezone and maybe a couple more, and that is a 
shame for D, especially since these problems have been around for so long.

-- 
Carlos Santander Bernal