George Gatling wrote:

> All the same, the seconds to date/time provides a "is DST" flag... so there 
> could still be a boolean input on the format to string function regarding 
> whether to ignore the DST flag.  Just a thought though.

There could if it would be used at all!! The underlying Windows API functions
most probably simply ignore this flag and so do probably all other system APIs
including the Mac.
Also note that the flag as returned from the "seconds to date/time" at
least until LabVIEW 6.1, does not indicate the DST state of the timestamp
entered in reference to the current DST switching times for the current time
zone but the DST state of the current system time. As such it is highly
useless or in fact even misleading.

LabVIEW 7.0 fixed that to a certain amount, at least for the "seconds to date/time" 
function which seems to correctly indicate the daylight saving
time flag in relation to the current locale and the actual time stamp
converted.
I say fixed it to some amount because the actual offset in seconds used
is still in relation to the current timezone and DST of the current time.

Consequently "date/time to seconds" blissfully ignores the DST flag
completely and just simply uses the current time zones and times offset
to convert a time cluster into a timestamp.

This behaviour although somewhat strange and illogical is however highly desirable in 
terms of functional compatibility to earlier LabVIEW versions
as many programs might suddenly misbehave if this had changed.

Also note that the actual GMT delta library I mentioned earlier on
downloadable from Developer Exchange has actually a problem when upgraded
to LabVIEW 7.0 at least in the version I downloaded sometimes last year.
It is not because of the change of above functions (which has not changed
at all in this part) but because the hidden timestamp used as reference
(Jan 1, 1980 0:00) gets modified when the VI is loaded into LabVIEW 7.0
by adding either the current DST offset or the current timezone offset
(I'm not sure which one as they are both 1 hour for me at the moment)
to it.

Rolf Kalbermatter
CIT Engineering Nederland BV    tel: +31 (070) 415 9190
Treubstraat 7H                  fax: +31 (070) 415 9191
2288 EG Rijswijk        http://www.citengineering.com
Netherlands             mailto:[EMAIL PROTECTED]
 



Reply via email to