Re: [Chicken-users] srfi-19 timezone problems

[Kon Lovett]

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On Mar 27, 2007, at 2:57 PM, Hans Bulfone wrote:

>
<snip>
> np, thanks for the quick fix!
>
> but i still get the wrong time:
>
> #;7> (values (current-date) (current-date (local-timezone-locale))  
> (current-date 7200))
> #,(date 403000116 9 36 21 27 3 2007 0 UTC #f 2 86)
> #,(date 403000000 9 36 20 27 3 2007 -3600 CET #t #f #f)
> #,(date 403000000 9 36 23 27 3 2007 7200 #f #f #f #f)
> #;8> (timezone-locale-offset (local-timezone-locale))
> -3600
> #;9>
>
> the timezone offset should be 3600 during winter and 7200 during
> summer time (which has started last weekend).
>
> i think the time zone offset from the locale is applied with the
> wrong sign.

Yes. The TZ env-var is parsed properly by the locale egg but the tz- 
offset was used incorrectly by my srfi-19 code. (Well, I did have my  
locale documentation wrong. Said the opposite of what is true.)

2.6.3 will be available Wed (earlier if I can figure out why I can't  
build).

Sorry, again,
Kon

> i just found this in libc.info about the TZ variable:
>
> ------------------------------------------------------------
>    The first format is used when there is no Daylight Saving Time (or
> summer time) in the local time zone:
>
>      STD OFFSET
>
>    The STD string specifies the name of the time zone.  It must be
> three or more characters long [...]
>
>    The OFFSET specifies the time value you must add to the local time
> to get a Coordinated Universal Time value.  It has syntax like
> [`+'|`-']HH[`:'MM[`:'SS]].  This is positive if the local time zone is
> west of the Prime Meridian and negative if it is east.  The hour must
> be between `0' and `23', and the minute and seconds between `0' and
> `59'.
>
>    For example, here is how we would specify Eastern Standard Time,  
> but
> without any Daylight Saving Time alternative:
>
>      EST+5
> ------------------------------------------------------------
>
> this is the opposite of the normal way to specify the time zone offset
> where you specify the time value you must add to UTC to get local time
> (like in ISO 8601)
>
> so CEST-2:00 would be correct:
>
> address@hidden:~$ date ; TZ=CEST-2 date ; TZ=Europe/Vienna date
> Tue Mar 27 23:54:04 CEST 2007
> Tue Mar 27 23:54:04 CEST 2007
> Tue Mar 27 23:54:04 CEST 2007
> address@hidden:~$
>
> bye,
> hans.

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