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This queue is for tickets about the Time-Local CPAN distribution.

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The Basics
Id: 11662
Status: resolved
Priority: 0/
Queue: Time-Local

People
Owner: DROLSKY [...] cpan.org
Requestors: roger.picton [...] opre.co.uk
Cc:
AdminCc:

Bug Information
Severity: Normal
Broken in: 1.10
Fixed in: 1.12_01



Subject: Time::Local v1.10 problem with transition to GMT daylight saving time
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When using ActivePerl 5.8.6.811 (which includes Time::Local v1.10) on Windows NT, 2000 and XP with a time zone of GMT, timelocal returns the wrong number of seconds from the epoch when given a time during the 24 hours after the transition from standard to daylight saving time. The following shows this (to see the problem you must switch your PC to the "(GMT) Greenwich Mean Time : Dublin, Edinburgh, Lisbon, London" time zone if it's not already there): use Time::Local; use POSIX; foreach $hour (0..23) { # GMT to BST switch will occur on 27th March 2005 $secs = timelocal(0, 0, $hour, 27, 2, 2005); printf "Hour %2d -> %s\n", $hour, strftime( '%Y-%m-%d %H:%M:%S %z', localtime($secs)); } The same problem occurs with Time::Local v1.11 (from CPAN) but not with v1.07 (which was included with ActivePerl 5.8.4.810). The problem doesn't occur with most other time zones I've tried but does occur with "(GMT-01:00) Azores, Cape Verde Is." just after the opposite transition (from daylight saving to standard time - 30th October 2005). I think the problem may be caused by the introduction of the "one-day delta" at v1.10 and v1.11 (line 156 in v1.10) which wasn't there at v1.07. If the year is given as >= 100 (as above) $delta will be -86400. This means that the localtime call on the following line will think it's in standard time causing $zone_off on line 160 to be zero. In turn that will cause the 'or return $loc_t' on line 161 to return. This may also explain the "Azores" case above (their daylight saving time is actually GMT). Also, changing the year supplied in the code above from 2005 to 5 gives the right answer - presumably because $delta will now be +86400 and so gives a localtime during daylight saving. I don't understand the details of the code well enough to suggest a patch but I hope the above will give an expert enough to go on! Roger Picton Fujitsu Services Telford, UK roger.picton@opre.co.uk 25th February 2005
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On Fri Feb 25 11:09:10 2005, guest wrote: Show quoted text
> I think the problem may be caused by the introduction of the "one-day > delta" at v1.10 and v1.11 (line 156 in v1.10) which wasn't there at > v1.07. If the year is given as >= 100 (as above) $delta will be -86400. > This means that the localtime call on the following line will think it's > in standard time causing $zone_off on line 160 to be zero. In turn that > will cause the 'or return $loc_t' on line 161 to return.
This is all gone in 1.13. Can you try this version?
Subject: RE: [rt.cpan.org #11662] Time::Local v1.10 problem with transition to GMT daylight saving time
Date: Wed, 20 Sep 2006 16:10:18 +0100
To: <bug-Time-Local [...] rt.cpan.org>
From: "Operational Research, Telford" <oru [...] opre.co.uk>
I've rerun my original tests with Time::Local v1.13 from CPAN on ActivePerl 5.8.8.819 and it gives the same answers as I originally got with 1.07, so I think we can declare the bug fixed. Thanks for your help with this! Regards, Roger Picton Fujitsu Services Telford, UK roger.picton@opre.co.uk Show quoted text
-----Original Message----- From: via RT [mailto:bug-Time-Local@rt.cpan.org] Sent: 17 September 2006 17:07 To: roger.picton@opre.co.uk Subject: [rt.cpan.org #11662] Time::Local v1.10 problem with transition to GMT daylight saving time <URL: http://rt.cpan.org/Ticket/Display.html?id=11662 > On Fri Feb 25 11:09:10 2005, guest wrote:
> I think the problem may be caused by the introduction of the "one-day > delta" at v1.10 and v1.11 (line 156 in v1.10) which wasn't there at > v1.07. If the year is given as >= 100 (as above) $delta will be -86400. > This means that the localtime call on the following line will think it's > in standard time causing $zone_off on line 160 to be zero. In turn that > will cause the 'or return $loc_t' on line 161 to return.
This is all gone in 1.13. Can you try this version?


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