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From: Kilgallen@SpamCop.net (Larry Kilgallen)
Newsgroups: comp.lang.ada
Subject: Re: How to cache output of the compiler aka ccache
Date: 18 Mar 2005 21:25:02 -0600
Organization: LJK Software
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Date: 2005-03-18T21:25:02-06:00
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In article <pJqdnQxLIP40rqbfRVn-uw@megapath.net>, "Randy Brukardt" <randy@rrsoftware.com> writes:
> "Simon Wright" <simon@pushface.org> wrote in message
> news:x7vekeciwtj.fsf@smaug.pushface.org...
> ...
>> We had an interesting bug with 3.16a1 on Windows where compilations
>> ran slower if the compiler had been installed in the winter months
>> (outside daylight saving time) -- a feature involving the Windows
>> installer, I think; the timestamps in the library were all one hour
>> out.
> 
> This is a bizarre Windows "feature". When daylight saving time changes, all
> of the time stamps on your existing files will change one hour. (If you
> don't believe me, check it out when the time changes.)
> 
> If you have code the previously stored the time stamp somewhere (say in a
> dependency file), it will suddenly be off an hour, and thus will mismatch.
> 
> Janus/Ada doesn't have the problem with the core runtime (since the source
> isn't supplied), but sometimes a daylight saving time change will force a
> rebuild of an entire project. I've never figured out a good solution, since
> the behavior is so odd.

It seems to me that one should instruct Windows that one is in a
place where Daylight Savings Time is not honored.  To ask the
computer to go switching times away from reality is asking for
trouble.