MPI_COMM_DUP_FN - Built-in MPI function to simple-mindedly copy communicator attributes.

       The LAM Team would like the thank the MPICH Team for the handy program to generate man  pages  ("doctext"
       from  ftp://ftp.mcs.anl.gov/pub/sowing/sowing.tar.gz ), the initial formatting, and some initial text for
       most of the MPI-1 man pages.

comm   - communicator (handle)
       key    - key value (integer)
       extra  - extra state
       attrin - in value for attribute

       dupfn.c

LAM/MPI 7.1.4                                       6/24/2006                                 MPI_COMM_DUP_FN(3)

       For  more  information,  please  see the official MPI Forum web site, which contains the text of both the
       MPI-1 and MPI-2 standards.  These documents contain detailed information about each MPI function (most of
       which is not duplicated in these man pages).

       http://www.mpi-forum.org/

       MPI_COMM_DUP_FN -  Built-in MPI function to simple-mindedly copy communicator attributes.

       This  function  blindly  byte-copies  attributes  on  communicators.  It is the default atrribute-copying
       function for communicators.  This function will always return MPI_SUCCESS , and flag will always  be  set
       to 1.

       The actual copy is performed by the code

       *((void **) attrout) = attrin;

       If this simple assignment is not sufficient for your attributes, you will need to reassign the attribute-
       copying function on relevant keyvals on communicators with the MPI_Comm_keyval_create function.

       All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have an additional argument ierr at the
       end of the argument list.  ierr is an integer and has the same meaning as the return value of the routine
       in C.  In Fortran, MPI routines are subroutines, and are invoked with the call statement.

       All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in Fortran.

attrout
              - out value for attribute
       flag   - 1 if attribute copied successfully, 0 otherwise (logical)

       MPI_Comm_keyval_create

       #include <mpi.h>
       int MPI_COMM_DUP_FN(MPI_Comm comm, int key, void *extra,
                          void *attrin, void *attrout, int *flag)