[Gambas-user] forcing time zone localization

[Benoît Minisini]

Le 01/02/2013 08:37, Kevin Fishburne a écrit :
> On 01/31/2013 04:29 AM, Benoît Minisini wrote:
>> Le 31/01/2013 08:35, Kevin Fishburne a écrit :
>>> I have a client/server application in which the server tells the client
>>> the date and time. The date and time is calculated by the server from an
>>> arbitrary starting point and at an arbitrary scale, but based on the
>>> server's system clock so that time still "advances" when the server
>>> application is not running. The client and server display the date and
>>> time using code like this:
>>>
>>> Format$(CDate(DateCurrent), "mmmm d, yyyy, hh:nn:AM/PM")
>>>
>>> I need Gambas to use a specific time zone for the client and server,
>>> ignoring the system time zone. I've read this:
>>>
>>> http://gambasdoc.org/help/doc/locale?v3
>>>
>>> Is what I'm trying to do possible? What environment variable should I
>>> set in Gambas ($LC_ALL, $LANG), and is there an ISO or table of codes to
>>> choose from? I've looked at ISO 3166 here:
>>>
>>> http://en.wikipedia.org/wiki/ISO_3166
>>>
>>> Thanks.
>>>
>> You should not need to use a different timezone for a program. Otherwise
>> you can use the TZ environmental variable.
>>
>> But you can get the current timezone by doing: Round(Frac(Date(now)) *
>> 24). (Meaning that the time is UTC + that value. TZ is set with the
>> opposite).
>>
>> Then you can convert a local time to GTM time for your communication
>> between server and client.
>>
>> Dunno if it fits your need.
>>
>> Regards,
>>
>
> Just spent two hours on this with no success. I have the server's OS set
> to use Venezuela's time zone because it has no DST. The client OS is
> UTC/GMT -5 (US Eastern). The client and server start with the same raw
> date/time obtained through CFloat(Now) on the server. The client's
> date/time is different than the server's by 30 minutes due to
> localization used by Format$.
>
> I created a TZ environment variable and regardless of its value it has
> no effect on the output of Format$. Is the TZ environment variable
> ignored or not used by Format$? There may be a solution staring me in
> the face based on the information you gave me, but I can't see it
> despite my efforts. The really stupid way to solve the problem would be
> to set the client and server OS time zones to be the same, but that
> would correctly inform the user that I was an idiot. ;)
>

OK... You must understand that Gambas stores all date/time in UTC 
internally. The timezone is applied only when converting that date/time 
to a string.

So you can safely exchange date/time between your client and your server 
by using the WRITE instruction or by converting the date/time to a 
number with CFloat() before exchanging it.

Regards,

-- 
Benoît Minisini