[netCDF #MVM-110226]: HDF5 and configure

lools good; might change
...Therefore I have
to ...Therefore we have

Russ Rew wrote:
> New Staff Reply: HDF5 and configure
> 
> Hi Mathieu,
> 
>> we were trying to compile HDF5 with configure
>> and we found that there is no option for hdf5 in it:
>> ------
>> dutour@dutour-Satellite-L655:~/netcdf-4.1.3$ ./configure --help | grep -i
>> hdf
>> --disable-netcdf-4      build with netcdf-4 (HDF5 and zlib required)
>> --enable-netcdf4        build with netcdf-4 (HDF5 and zlib required)
>> --enable-hdf4           build netcdf-4 with HDF4 read capability (HDF4,
>> HDF5
>> --enable-hdf4-file-tests
>> get some HDF4 files from Unidata ftp site and test
>> Forecast conventions. (Requires netCDF-4 and HDF5)
>> Specify default file cache chunk size for HDF5
>> files
>> file chunk cache chunk for HDF5 files (should be
>> for HDF5 files (a number between 0 and 1,
>> ------
>> We would have expected a --with-hdf5-prefix=.... but there is no
>> such thing. Instead we used CPPFLAGS and LDFLAGS.
>>
>> There may be some reason for that but right now this looks very
>> strange.
> 
> The change in how the locations of the various libraries are handled
> was to fix a bug caused by using "--with-hdf5=".  
> 
> I need to promote this to an FAQ answer, so people can see what lead
> to this decision.  Here's a draft of what the FAQ will look like:
> 
> Q: Why was the "--with-hdf5=" configure option dropped in netCDF
>    versions after 4.1.3?
> 
> A: It fails badly in the area of 32/64 bit platforms (i.e. platforms
>    that want both a 32 bit and a 64 bit version of the library
>    installed at the same time.) It also adds a lot of code to our
>    build system.
> 
>    Since this is not the normal way that packages are built, the use
>    of these options caused netCDF to require more documentation, and,
>    what's worse, required that each installer read the documentation
>    (this is not the usual case with Unix packages, which can generally
>    be built without setting any options.)
> 
>    More importantly, the use of the --with-hdf5 option (and similar
>    ones like --with-zlib, --with-szlib, --with-pnetcdf, --with-hdf4)
>    cause two serious bugs:
> 
>    1 - No way for these options to work on platforms that have libraries
>        in /lib and /lib64 for 32 and 64 bit builds.
>    2 - Caused problem for for cross-compiles link the mingw32 build and
>        builds on some supercomputers.
> 
>    Ultimately, it is only possible for the builder of the software to
>    know what settings to use in the various FLAG environment
>    variables. All of our attempts to "help" in this area just result
>    in problems for some small (but important) fraction of the user
>    base. Therefore I have decided that all these options must go, both
>    in netCDF and in libCF. I regret the inconvenience this may cause
>    users who have become accustomed to these options.
> 
>    A fuller explanation can be found here:
>    
>      https://www.unidata.ucar.edu/jira/browse/NCF-20
>    
>    and the conspiracy behind this decision is explained in the last
>    paragraph of this netcdfgroup mailing list posting:
> 
>     
> http://www.unidata.ucar.edu/mailing_lists/archives/netcdfgroup/2011/msg00345.html
> 
> --Russ
> 
> 
> Russ Rew                                         UCAR Unidata Program
> address@hidden                      http://www.unidata.ucar.edu
> 
> 
> 
> Ticket Details
> ===================
> Ticket ID: MVM-110226
> Department: Support netCDF
> Priority: Normal
> Status: Closed
> Link:  
> https://www.unidata.ucar.edu/esupport/staff/index.php?_m=tickets&_a=viewticket&ticketid=20585



Ticket Details
===================
Ticket ID: MVM-110226
Department: Support netCDF
Priority: Normal
Status: Closed