[MPIWG Fortran] Provide Fortran datatypes if Fortran bindings not provided?

Jeff Squyres (jsquyres) jsquyres at cisco.com
Thu Feb 18 12:42:05 CST 2016

On Feb 18, 2016, at 1:31 PM, Jeff Hammond <jeff.science at gmail.com> wrote:
> > Please tell me why we want to do something different for Fortran.
> Seems to be a good point.
> What is mpich doing if there is no accompanying Fortran compiler?
> Full mpi.h from my Clang MPICH builds with FC=false attached.  Relevant excerpt below.
> /* Fortran types */
> #define MPI_COMPLEX           ((MPI_Datatype)MPI_DATATYPE_NULL)

It looks like OMPI does a mix of setting some Fortran datatypes to (effectively) MPI_DATATYPE_NULL and others to what we guess/assume they should be equivalent to (e.g., MPI_INTEGER --> MPI_INT).

> Middleware that compiles but cannot be used in any nontrivial way because MPI_DATATYPE_NULL may (at least with Open-MPI) cause the program to abort.  I don't see a problem in breaking compilation when successful compilation today leads to unsuccessful execution.


Jeff Squyres
jsquyres at cisco.com
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