#450 Time('O') jumps 2hrs for Daylight Savings Time

[SimonT]

Hi - using 3.9.0 on W7 and W8.1 Europe time zone: A call to Time('O') went from +1 hours pre-DST to +3 hours post-DST (should be +2). The documentation mentions that it can be unreliable for some OS's, so not sure whether this is a bug or a Windows issue?

Thanks,
Simon T.

[Mark Hessling]

If the only change in the environment is the date on which the test was run; ie Regina version the same, Windows OS the same, then it will be a Windows issue. Time('O') is determined by subtracting GMT from local time, and if DST is in effect, adds an hour. All time information is obtained from the operating system.

[Arthur T.]

I don't think this is invalid. If the operating system returns the DST-corrected local time and GMT, then your 1-hour correction forces an incorrect value in Regina. This is happening tome, too. All levels of Regina from through 3.9.3 on Windows 2000 & Windows10.

[Stefan Haubenthal]

Indeed, remove this code

if ( tmptr->tm_isdst )
   timediff += 3600;

https://stackoverflow.com/questions/46258930/

[Mark Hessling]

Applied as per Stefan's suggestion

[Paul Kislanko]

TIME('O') works, but on the last day of DST it appears that TIME('T') has the same bug:

parse version v; say v; say time() time(,time('t'),'t')
REXX-Regina_3.9.4(MT) 5.00 25 Oct 2021
12:41:47 13:41:47