bugGNU Octave - Bugs: bug #53908, Omissions in Documentation of...


bug #53908: Omissions in Documentation of tm_struct

Submitted by:  Ian McCallion <ianmcc>
Submitted on:  Tue 15 May 2018 11:50:00 AM UTC  
Category:  Documentation Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Documentation
Status:  None Assigned to:  None
Originator Name:  Open/Closed:  Open
Release:  4.4.0 Operating System:  Any

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Tue 15 May 2018 07:21:57 PM UTC, comment #3:

I think someone with access to Windows will have to try to get something working with GetTimeZoneInformation, GetDynamicTimeZoneInformation, and/or GetTimeZoneInformationForYear. The latter two are not available in older versions of Windows.

I guess this might look something like

but that's just off the top of my head without ever having used these functions before.

Mike Miller <mtmiller>
Project Administrator
Tue 15 May 2018 06:21:01 PM UTC, comment #2:

Looking on MSDN, the aptly named GetTimeZoneInformation function seems to fit the bill.

Ian McCallion <ianmcc>
Tue 15 May 2018 05:43:02 PM UTC, comment #1:

The value of gmtoff is meant to be the number of seconds offset between your local time and UTC, so in your case it ought to be 3600.

I think we would be happy to add support to fill in this offset if it is at all possible with the Windows API. If there is a way to get that information for a given time value, it can be added. Otherwise we should document that it is not implemented on some systems.

Mike Miller <mtmiller>
Project Administrator
Tue 15 May 2018 11:50:00 AM UTC, original submission:

A. I'm in the UK and on Windows (4.2.2 and 4.4.0):

> >> localtime(time)
> usec = 178342
> sec = 59
> min = 32
> hour = 8
> mday = 12
> mon = 4
> year = 118
> wday = 6
> yday = 131
> isdst = 1
> gmtoff = 0
> zone = GMT Daylight Time

Clearly gmtoff should be 1 as it is currently daylight time.

I would suggest this is a code bug. However I have been asked to submit it as a documentation bug with the fix being to state at the start of section 36.1 of the manual that gmtoff is not implemented in Windows.

B. The mktime function takes a tm_struct as parameter. However the values for gmtoff and zone are ignored. This is working as designed (because mktime uses the TZ environment variable to obtain timezone information). This fact should be mentioned in the documentation.

Ian McCallion <ianmcc>


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