All,

I'm sort of new to MPICH and I'm encountering one call that works with Open MPI but not MPICH. As such, I'm wondering if I built MPICH incorrectly or incompletely (always easy to miss a configure flag!).

To wit, I have a code like:

program main

   use mpi

   use iso_fortran_env, only: INT64

   use iso_c_binding, only: C_PTR

   integer(kind=INT64) :: sz

   type (c_ptr) :: ptr

   call MPI_Alloc_mem(sz, MPI_INFO_NULL, ptr, ierror)

end program main

If I compile with GCC 12.1 + Open MPI 4.1.3, all is well:

$ mpifort --showme:version

mpifort: Open MPI 4.1.3 (Language: Fortran)

mathomp4@discover23 ~/MPITests/CPtr master ?25

$ mpifort support_for_mpi_alloc_mem_cptr.F90

mathomp4@discover23 ~/MPITests/CPtr master ?25

$ echo $?

0

I'll also say Intel MPI builds this code as well.

But with MPICH 4.1.2 I just built:

$ mpifort support_for_mpi_alloc_mem_cptr.F90

support_for_mpi_alloc_mem_cptr.F90:9:53:

    9 |    call MPI_Alloc_mem(sz, MPI_INFO_NULL, ptr, ierror)

      |                                                     1

Error: Type mismatch in argument 'baseptr' at (1); passed TYPE(c_ptr) to INTEGER(8)

Now, my configure lines to Open MPI and MPICH are pretty boring, so the resulting mpiforts are as well:

$ mpifort -show

gfortran -I/discover/swdev/gmao_SIteam/MPI/openmpi/4.1.3/gcc-12.1.0/include -pthread -I/discover/swdev/gmao_SIteam/MPI/openmpi/4.1.3/gcc-12.1.0/lib -L/discover/swdev/gmao_SIteam/MPI/openmpi/4.1.3/gcc-12.1.0/lib -lmpi_usempif08 -lmpi_usempi_ignore_tkr -lmpi_mpifh -lmpi

$ mpifort -show

gfortran -I/discover/swdev/gmao_SIteam/MPI/mpich/4.1.2/gcc-12.1.0/include -I/discover/swdev/gmao_SIteam/MPI/mpich/4.1.2/gcc-12.1.0/include -L/discover/swdev/gmao_SIteam/MPI/mpich/4.1.2/gcc-12.1.0/lib -lmpifort -Wl,-rpath -Wl,/discover/swdev/gmao_SIteam/MPI/mpich/4.1.2/gcc-12.1.0/lib -Wl,--enable-new-dtags -lmpi

But I see Open MPI has that "mpi_usempi_ignore_tkr", is it possible that's what is doing it?

Perhaps we just need to recode the code (using transfer, etc?)

Thanks for any help,

Matt