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Message-ID: <504B7914.1080200@apache.org>
Date: Sat, 08 Sep 2012 18:57:56 +0200
From: Herbert Duerr <hdu@apache.org>
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To: ooo-dev@incubator.apache.org
Subject: Re: *** Warning: .LOW_RESOLUTION_TIME
References: <504B296F.5020203@t-online.de>
In-Reply-To: <504B296F.5020203@t-online.de>
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Hi Regina,

On 09/08/2012 01:18 PM, Regina Henschel wrote:
> building with MSVC 2008 express on WinXP, I get a lot of warnings of the
> kind:
> make: *** Warning: .LOW_RESOLUTION_TIME file `<path
> part>/solver/350/wntmsci12/<path part>` has a high resolution time stamp
>
> It builds and the build is usable nevertheless.
>
> What does this warning mean?

Tools such as make or solenv's deliver depend on the relative order of 
timestamps. E.g. make rebuilds an object file only if the source file is 
newer.

Some filesystems, archive formats and some tools strip the sub-second 
part of a file timestamp away when the file gets copied around. This can 
result in a wrong relative time order of two files or it can result in 
updated files not being recognized as updated. The special gnumake 
target LOW_RESOLUTION_TIME is there so that even in that case the 
pseudo-wrong order doesn't cause missed dependencies.

As far as I understand the make output above LOW_RESOLUTION_TIME warns 
that it has been told that sub-second parts of timestamps are stripped 
away but the sub-second parts are still there nevertheless.

> Is there a way to avoid it?

IMHO make should be happy to find that the subsecond parts are not 
stripped and should not warn about it. Another solution could be that 
make ignores the subseconds itself for the files mentioned in a rule.

If the only way was to deal with it in our codebase then the proper 
action would be to check in the configure step which tools, which 
directories, etc. strip away the sub-seconds and only issue the special 
target if files were handled by these tools/filesystems/etc. Solving it 
that wouldn't be much fun though.

Hope that helps,
Herbert