fortran: ierror keyword argument not handled correctly in Fortran 90 mpi module bindings

[mathomp4]

I have some sample code that does not compile with MPICH 4.1.2:

program hello_world
   use mpi
   implicit none
   integer :: status
   call MPI_Init(ierror=status)
   call MPI_Finalize(ierror=status)
end program hello_world

With MPICH:

$ mpifort init_status.F90
init_status.F90:5:24:

    5 |    call MPI_Init(ierror=status)
      |                        1
Error: Keyword argument 'ierror' at (1) is not in the procedure; did you mean 'ierr'?
init_status.F90:6:28:

    6 |    call MPI_Finalize(ierror=status)
      |                            1
Error: Keyword argument 'ierror' at (1) is not in the procedure; did you mean 'ierr'?

Every other stack I try supports this. Per the MPI Standard, I'm pretty sure the Fortran interfaces say the final argument will be IERROR.

Per a colleague of mine (@tclune) on the Fortran Standards Committee:

Explicit interfaces for Fortran procedures include the keywords, i.e., the spelling of the procedure arguments. The use mpi mechanism is intended to provide explicit interfaces to MPI procedures. The MPI standard specifies the final argument is spelled "IERROR", not "IERR".

Note, that this works:

program hello_world
   use mpi
   implicit none
   integer :: ierror
   call MPI_Init(ierror)
   call MPI_Finalize(ierror)
end program hello_world

works because you aren't using keywords. Also, the first program works if you use mpi_f08 because it seems to handle ierror keyword correctly. But the Fortran 90 bindings seem to have been constructed such that it thinks the last argument is called ierr (as in C) and not ierror (as it should be in Fortran).

[hzhou]

Thank you for the report! We will fix it.