[Dune] [Dune-Commit] dune-localfunctions r828 - in trunk/dune/localfunctions: common lagrange test

[Carsten Gräser]

No one seems to know which old compilers are still used
with dune. As the developers all seem to use more recent
compilers it would be nice to also have feedback from the
users which compilers/versions are actually used.

Otherwise the 'Perhaps compiler-x.y is still used' argument
are valid forever. When do we want to drop support for older
(and less standard conforming) compilers ?

E.g. the first gcc-4.x release is about 5 years old and the last
gcc-3.4.x release about 4 years.

Of course supporting other compilers (xlc, sun ?) would
be nice, but this seems to be a different issues. If we
want to have support for them this is in no way guaranteed
by supporting older gcc/icc versions.

Regards
Carsten

Am 12.02.2010 15:57, schrieb Andreas Dedner:
> Of course I would agree that xlc would be good to have on the support list.
> But is there any direct correspondence between gcc 3.4 and xlc?
> I think that especially testing with gcc 3.4 although we are close to
> having a gcc 4.5 is unnecessary - bur is adding a test for xlc (if
> possibl)e not
> a different issue?
> 
> Andreas
> 
> Markus Blatt wrote:
>> Hi,
>>
>> On Fri, Feb 12, 2010 at 02:25:42PM +0100, Oliver Sander wrote:
>>  
>>> I agree with this.  Do we know of actually users who need the backward
>>> compatibility and cannot stay with Dune 1.2.2 at the same time?
>>>
>>>
>>> Andreas Dedner schrieb:
>>>    
>>>> Hi,
>>>> I think we have to discuss to what extend we really want to still
>>>> support these old compiler - especially icc 7 and gcc 3.4.
>>>> Could somebody who really uses them comment on this. For example
>>>> in Karlsruhe on their cluster they have gcc 4.2 and icc 12.
>>>> We said we wanted to have the compatibility for 2.0 and lets go ahead
>>>> with that but some of the fixes checked in to manage this have  not
>>>> been
>>>> very nice code and if nobody requires the old compiler I would
>>>> suggest to revert some of the changes (e.g. in 
>>>> dune-lf/dune/lf/utility/field.hh)
>>>> in the trunk and to drop those old compilers from the compatibility
>>>> list
>>>> for the next release.
>>>> Best
>>>> Andreas
>>>>       
>>
>>
>> While I agree that few people use this compilers, I still think
>> dropping support for them is not the way to go. The more compilers we
>> support the more standard compliant we are. In the last weeks several
>> non standard-conformant things were patched due to supporting these
>> rather old compilers.
>>
>> My fear is that if we drop support we will maybe not drop standard
>> conformance, but use more and more features that are just supported by
>> the leading pack of the compilers. This would prevent other compilers
>> (e.g. IBM's xlc) from catching up.
>>
>> There are compilers on supercomputers (xlc on the Blue Gene) that I
>> would like to see being supported by Dune. IMO support here means giving
>> them time to implement the standard correctly before DUNE moves to the
>> next standard.
>> Having said that, I agree that using typedefs in code to do this is a
>> real pain and not beautiful/readable etc.
>>
>> Just my 2 cents.
>>
>> Marus
>>
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>>   
> 
> 
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-- 
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Carsten Gräser           | phone: +49-30 / 838-75349
Freie Universität Berlin | fax  : +49-30 / 838-54977
Institut für Mathematik  | email: graeser at math.fu-berlin.de
Arnimallee 6             |
14195 Berlin, Germany    | URL  : http://page.mi.fu-berlin.de/graeser
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