On Feb 13, 2008, at 5:07 PM, Craig E. Rasmussen wrote:

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! I think we should provide better interfaces to command line arguments. ! It can be done through GET_COMMAND and GET_COMMAND_ARGUMENT. ! MPI_Init should be able to pass back something like modified C argc and argv arguments.

err = MPI_Init()

What do you mean?

Pretty much what you do (see below).

I think that if an MPI implementation needs the argv, it can have its own implementation of MPI_Init in Fortran that calls GET_COMMAND and GET_COMMAND_ARGUMENT; the argc/argv arguments to MPI_INIT in C are allowed be NULL,NULL.

Right. I'm thinking that we can wrap MPI_Init so that the functionality is to pass back essentially the argc, argv list that C users get.

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! We need to figure out the type of MPI handles. ! Currently I'm leaning toward TYPE(C_PTR) rather than ! the INTEGER(MPI_HANDLE_KIND) Jeff and I used in our paper.

Will this be able to handle MPI implementations that use integers as MPI handles in C?

So are we talking about global constants like MPI_COMM_WORLD? If so it looks like we can use the same global integers that are used in C. We would just initialize MPI_COMM_WORLD in Fortran MPI_Init to the address of the global C integer. If you can grok the Fortran, I've included the code snippets: ! the global integer in OMPI integer, bind(C) :: ompi_mpi_comm_world ! the declaration of the handle in Fortran type(C_PTR) :: MPI_COMM_WORLD ! the initialization in MPI_Init() MPI_COMM_WORLD = C_LOC(ompi_mpi_comm_world) Cheers, Craig