Re: mpi.h vs. hdf5.h

[Juan Pablo Carbajal]

On Tue, Mar 4, 2014 at 5:00 PM, Mike Miller <address@hidden> wrote:
> On Tue, Mar 4, 2014 at 16:36:14 +0100, Juan Pablo Carbajal wrote:
>> In Ubuntu 13.10 amd64 the configure script of default repository fails
>> to find HDF5 libraries. The error is misleading because what it fails
>> to find is the mpi.h headers.
>>
>> I this system hdf5.h is in the default include path (/usr/include),
>> but mpi is not.
>> The following call to the include script erases the warning.
>>
>> CPPFLAGS=-I/usr/lib/openmpi/include/;
>> CFLAGS=-I/usr/lib/openmpi/include/ ../default/configure
>>
>> Shall one add a test for MPI headers before the test for HDF5?
>
> This has been a long-standing issue, see many threads in the Octave
> lists and I think a couple of Debian bug reports or discussion
> threads. I suppose such a test could be added, but I strongly dislike
> Octave having to know these details about HDF5. MPI is completely
> optional with HDF5 and Octave could not care less whether it was built
> with or without MPI, or which MPI library was used.
>
> By the way, this is exactly the error you were having in your thread
> last week about an error installing the signal package. I gave a
> reason for the error in that context, see my reply [1]. Now that you
> are rebuilding Octave, you're encountering the same exact error.
>
> One workaround is to install libhdf5-dev (which will uninstall
> libhdf5-openmpi*). This is what I usually recommend if you don't
> really need MPI-enabled HDF5.
>
> My workaround is to always build Octave with
> CPPFLAGS=-I/usr/include/mpi, this is sufficient to find MPI header
> files if HDF5 needs them, otherwise they are ignored, and I can switch
> HDF5 implementations without having to worry about which one I
> installed last. This option is also saved and used in subsequent calls
> to mkoctfile.
>
> [1] 
> http://octave.1599824.n4.nabble.com/OF-signal-Compilation-errors-due-to-mpi-h-tp4662484p4662490.html
>
> --
> mike

I see... I kind of understanding this issue just now, though I have
faced it many times.
Thanks for the comprehensive answer.