NAG compiler and MPICH 4.0

[ivanpribec]

@nncarlson

I’m thinking it must be an inadequacy in the MPICH build system, which when it’s compiling the C code for the Fortran API needs to find for the correct ISO_Fortran_binding header file.

This issue was also discussed in the thread:

Is ISO_Fortran_binding.h compatible for different Fortran ABIs?

The C compiler can generate the correct ABI if the corresponding ISO_Fortran_binding.h is used. In case Intel Fortran is correctly setup the include directory of the Intel compilers should be in the CPATH environment variable and therefore prefer the ISO_Fortran_binding.h of Intel Fortran over the GFortran one. However, you have to be careful about your environment and include paths, if the build of the Fortran and C side are separated, an incorrect ABI could be generated if the wrong header i…

Just linking the discussion if anyone wants to add a comment there.