Too bad, at least for me this makes the ISO_Fortran_binding.h look like a step back when interfacing to C. For module files Fortran compilers usually choke on modules produced by other vendors, yet a C compiler will happily compile against any ISO_Fortran_binding.h found somewhere in the include path and maybe horribly fail at runtime. There are a few macros around which could help detect this on the C side, however those won’t be available on the Fortran side.