Sean argues the point well.  I would add that having a special set of flags
for one file should be done as a last resort (e.g., as a temporary work
around a compiler bug, in which case a reference to the bug report should
be provided).   In other cases (e.g., tests like "size > size+1" replaced
by "size == INT_MAX") it is better to rely on a defined constant than some
potentially undefined behaviour.

In this spirit, would it be better to #define the required values (and
perhaps provide checks to let us know when a value is incorrect)?  Perhaps
the existing code could provide a stand-alone tool to help compute values
for new compilers/platforms where RTFM or contacting the tool developers
fails.  In the long run, perhaps these values would be provided with the
compilers' headers.



On Thu, Oct 17, 2013 at 4:47 PM, Raymond Lu <[email protected]> wrote:

> Sean,
>
> Several of us including Quincey and Elena looked at the issue.  We decided
> that since the algorithm is trying to detect the alignment of integers,
> ideally the flag -fcatch-undefined-behavior and other optimization flags
> shouldn't to be used for H5detect.c. In the future, we can separate flags
> for H5detect.c from the rest of the library.
>
> (For those who don't know what Issue 8147 is: CLANG compiler on mac
> machines with the options -fcatch-undefined-behavior and -ftrapv catches
> some undefined behavior in the alignment algorithm of the macro DETECT_I in
> H5detect.c.)
>
> Please let us know your thoughts.
>
> Thanks.
>
> Ray
>
>
> On Oct 9, 2013, at 3:48 PM, Elena Pourmal wrote:
>
> Sean,
>
> Unfortunately the bug was not fixed, but its priority has been bumped
> (clang is one of the compilers that we should fully support).
>
> We are aware of the failures you have been posting to our CDash and will
> try to resolve the issue ASAP.
>
> Elena
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Elena Pourmal  The HDF Group  http://hdfgroup.org
> 1800 So. Oak St., Suite 203, Champaign IL 61820
> 217.531.6112
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
>
>
> On Oct 9, 2013, at 1:34 PM, Sean McBride <[email protected]>
>  wrote:
>
> On Tue, 8 Oct 2013 20:15:17 -0500, Elena Pourmal said:
>
> A pre-release candidate of HDF5 1.8.12 is available for testing and can
> be downloaded from the following location:
>
> *SNIP*
>
> The new release includes but is not limited to:
>
>
> Is HDFFV-8147 fixed?
>
> Cheers,
>
> --
> ____________________________________________________________
> Sean McBride, B. Eng                 [email protected]
> Rogue Research                        www.rogue-research.com
> Mac Software Developer              Montréal, Québec, Canada
>
>
>
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>
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>
>
> _______________________________________________
> Hdf-forum is for HDF software users discussion.
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>


-- 
George N. White III <[email protected]>
Head of St. Margarets Bay, Nova Scotia
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