[MPIWG Fortran] Questions about MPI_Comm_spawn
longb at cray.com
Tue Mar 25 09:59:16 CDT 2014
On Mar 25, 2014, at 9:51 AM, Junchao Zhang <jczhang at mcs.anl.gov> wrote:
> Hello, Fortran experts,
> p.377 of MPI3 defines prototype of MPI_Comm_spawn.
> MPI_Comm_spawn(command, argv, maxprocs, info, root, comm, intercomm, array_of_errcodes, ierror)
> CHARACTER(LEN=*), INTENT(IN) :: command, argv(*)
> I can understand that command is a variable-length character. I fetch its length by len(command). The Fortran compiler needs to pass in data of command, as well as length of command.
> But I can't understand argv(*). I interpret it as an assumed-size array of variable-length characters. Does that imply each argv(i) could have different lengths, e.g., len(argv(1)) may be different from len(argv(2))?
> I think it is unreasonable, since if that, the compiler has to pass in length of every element of argv(*).
It is unreasonable. All elements of a character array have the same length.
> Thank you
> --Junchao Zhang
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> mpiwg-fortran at lists.mpi-forum.org
Bill Long longb at cray.com
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