[Users] HDF5 and C++

[John Baker]

Hi,
     There was some discussion of HDF5 and c++ recently on
this list (See: 
http://lists.einsteintoolkit.org/pipermail/users/2010-September/000515.html 
). And also on the trac list in October.
In relation to these, our group has been having several problems
related to HDF5 and c++ recently.
      On many of the production environments where we run, there is no 
hdf5 build available which includes cpp support.  In particular a build 
failed when searching for libhdf5_hl_cpp.   We worked around this by 
removing these libraries from the list in 
ExternalLibraries/HDF5/HDF5.sh.  This seemed to work, but required our 
hacking the repository version of the code and presumably could cause a 
failure with any thorns needing HDF5 C++ support.
     At the same time (actually going back to the first ETK release) I 
have had difficulty compiling on MacOS, (the macports hdf5-18 doesn't 
support fortran or c++ with openmpi).  I don't generally need hdf5 when 
I'm doing development on my laptop, but it would be good to have it 
working.  I recently tried using the HDF5=BUILD option on Mac, but this 
seemed to lead to the same problem in different form.  The HDF5 
configuration failed with a complaint that --enable-cxx was incompatible 
with MPI compilers.
     Getting to the point now, I have some questions:

1. Is there a good reason why HDF5 needs the C++ libraries in Cactus?
2. Does hdf5 1.8.5 even support the c++ interface?
3. What should we be doing differently to work around these issues?

Thanks.
John.