C -*- Mode: Fortran; -*- 

C

C  (C) 2003 by Argonne National Laboratory.

C      See COPYRIGHT in top-level directory.

C

      program main

      implicit none

      include 'mpif.h'

      integer size, rank, ierr, errs, eclass

      integer color, comm, intercomm

      integer s1, s2

      character*(MPI_MAX_PORT_NAME) portname

      errs = 0

      call mtest_init( ierr )

      call mpi_comm_size( MPI_COMM_WORLD, size, ierr )

      call mpi_comm_rank( MPI_COMM_WORLD, rank, ierr )

      if (size .lt. 2) then

         print *, 'This example must have at least 2 processes'

         call mpi_abort( MPI_COMM_WORLD, 1, ierr )

      endif

C

C Part of this test is to ensure that lookups cleanly fail when

C a name is not present.  This code is used to ensure that the

C name is not in use  before the test.

C The MPI Standard (10.4.4 Name Publishing) requires that a process that

C has published a name unpublish it before it exits.  

C This code attempts to lookup the name that we want to use as the

C service name for this example.  If it is found (it should not be, but

C might if an MPI program with this service name exits without unpublishing

C the servicename, and the runtime that provides the name publishing

C leaves the servicename in use.  This block of code should not be necessary

C in a robust MPI implementation, but should not cause problems for a correct.

C

      call mpi_barrier( MPI_COMM_WORLD, ierr )

      call mpi_comm_set_errhandler( MPI_COMM_WORLD, MPI_ERRORS_RETURN, 

     &     ierr )

      call mpi_lookup_name( "fservtest", MPI_INFO_NULL, portname, ierr )

      if (ierr .eq. MPI_SUCCESS) then

          call mpi_unpublish_name( "fservtest", MPI_INFO_NULL, portname, 

     &        ierr )

      endif

      call mpi_barrier( MPI_COMM_WORLD, ierr )

C Ignore errors from unpublish_name (such as name-not-found)      

      call mpi_comm_set_errhandler( MPI_COMM_WORLD, 

     &     MPI_ERRORS_ARE_FATAL, ierr )

C

C The server (accept) side is rank < size/2 and the client (connect)

C side is rank >= size/2

      color = 0

      if (rank .ge. size/2) color = 1

      call mpi_comm_split( MPI_COMM_WORLD, color, rank, comm, ierr )

C

      if (rank .lt. size/2) then

C        Server

         call mpi_barrier( MPI_COMM_WORLD, ierr )

         if (rank .eq. 0) then

             call mpi_open_port( MPI_INFO_NULL, portname, ierr )

             call mpi_publish_name( "fservtest", MPI_INFO_NULL, 

     &            portname, ierr )

         endif

         call mpi_barrier( MPI_COMM_WORLD, ierr )

         call mpi_comm_accept( portname, MPI_INFO_NULL, 0, comm, 

     &                         intercomm, ierr )

         if (rank .eq. 0) then 

            call mpi_close_port( portname, ierr )

            call mpi_unpublish_name( "fservtest", MPI_INFO_NULL,

     &            portname, ierr )

         endif

      else

C        Client

         call mpi_comm_set_errhandler( MPI_COMM_WORLD,MPI_ERRORS_RETURN, 

     &                                 ierr )

         ierr = MPI_SUCCESS

         call mpi_lookup_name( "fservtest", MPI_INFO_NULL, 

     &                         portname, ierr )

         if (ierr .eq. MPI_SUCCESS) then

            errs = errs + 1

            print *, 'lookup name returned a value before published'

         else

            call mpi_error_class( ierr, eclass, ierr )

            if (eclass .ne. MPI_ERR_NAME) then

               errs = errs + 1

               print *, ' Wrong error class, is ', eclass, ' must be ',

     &          MPI_ERR_NAME

C              See the MPI-2 Standard, 5.4.4

            endif

         endif

         call mpi_comm_set_errhandler( MPI_COMM_WORLD, 

     &            MPI_ERRORS_ARE_FATAL, ierr )

         call mpi_barrier( MPI_COMM_WORLD, ierr )

         call mpi_barrier( MPI_COMM_WORLD, ierr )

         call mpi_lookup_name( "fservtest", MPI_INFO_NULL, 

     &                         portname, ierr )

C        This should not happen (ERRORS_ARE_FATAL), but just in case...

         if (ierr .ne. MPI_SUCCESS) then

            errs = errs + 1

            print *, ' Major error: errors_are_fatal set but returned'

            print *, ' non MPI_SUCCESS value.  Details:'

            call MTestPrintErrorMsg( ' Unable to lookup fservtest port', 

     &                               ierr )

C           Unable to continue without a valid port

            call mpi_abort( MPI_COMM_WORLD, 1, ierr )

         endif

         call mpi_comm_connect( portname, MPI_INFO_NULL, 0, comm, 

     &                          intercomm, ierr )

      endif

C

C Check that this is an acceptable intercomm

      call mpi_comm_size( intercomm, s1, ierr )

      call mpi_comm_remote_size( intercomm, s2, ierr )

      if (s1 + s2 .ne. size) then

         errs = errs + 1

         print *, ' Wrong size for intercomm = ', s1+s2

      endif

      call mpi_comm_free(comm, ierr)

C Everyone can now abandon the new intercomm      

      call mpi_comm_disconnect( intercomm, ierr )

      call mtest_finalize( errs )

      call mpi_finalize( ierr )

      end