!
! Copyright (C) by Argonne National Laboratory
!     See COPYRIGHT in top-level directory
!

      program bustit
      use mpi
      implicit none
      
      integer comm
      integer newtype
      integer me
      integer position
      integer type(5)
      integer length(5)
      integer (kind=MPI_ADDRESS_KIND) disp(5)
      integer bufsize
      integer errs, toterrs
      parameter (bufsize=100)
      character buf(bufsize)
      character name*(10)
      integer status(MPI_STATUS_SIZE)
      integer i, size
      double precision x
      integer src, dest
      integer ierr

      errs = 0
!     Enroll in MPI
      call mtest_init(ierr)

!     get my rank
      call mpi_comm_rank(MPI_COMM_WORLD, me, ierr)
      call mpi_comm_size(MPI_COMM_WORLD, size, ierr )
      if (size .lt. 2) then
         print *, "Must have at least 2 processes"
         call MPI_Abort( MPI_COMM_WORLD, 1, ierr )
      endif

      comm = MPI_COMM_WORLD
      src = 0
      dest = 1

      if(me.eq.src) then
          i=5
          x=5.1234d0
          name="Hello"

          type(1)=MPI_CHARACTER
          length(1)=5
          call mpi_get_address(name,disp(1),ierr)

          type(2)=MPI_DOUBLE_PRECISION
          length(2)=1
          call mpi_get_address(x,disp(2),ierr)

          call mpi_type_create_struct(2,length,disp,type,newtype,ierr)
          call mpi_type_commit(newtype,ierr)
          call mpi_barrier( MPI_COMM_WORLD, ierr )
          call mpi_send(MPI_BOTTOM,1,newtype,dest,1,comm,ierr)
          call mpi_type_free(newtype,ierr)
!         write(*,*) "Sent ",name(1:5),x
      else 
!         Everyone calls barrier in case size > 2
          call mpi_barrier( MPI_COMM_WORLD, ierr )
          if (me.eq.dest) then
             position=0

             name = " "
             x    = 0.0d0
             call mpi_recv(buf,bufsize,MPI_PACKED, src,                    &
     &            1, comm, status, ierr)
             
             call mpi_unpack(buf,bufsize,position,                         &
     &            name,5,MPI_CHARACTER, comm,ierr)
             call mpi_unpack(buf,bufsize,position,                         &
     &            x,1,MPI_DOUBLE_PRECISION, comm,ierr)
!            Check the return values (/= is not-equal in F90)
             if (name /= "Hello") then
                errs = errs + 1
                print *, "Received ", name, " but expected Hello"
             endif
             if (abs(x-5.1234) .gt. 1.0e-6) then
                errs = errs + 1
                print *, "Received ", x, " but expected 5.1234"
             endif
          endif
      endif
!
!     Sum up errs and report the result
      call mtest_finalize(errs)

      end
