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MPI_Comm_dup(3OpenMPI)                                                                MPI_Comm_dup(3OpenMPI)



NAME
       MPI_Comm_dup  -  Duplicates an existing communicator with all its cached information.


SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Comm_dup(MPI_Comm comm, MPI_Comm *newcomm)


Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_COMM_DUP(COMM, NEWCOMM, IERROR)
            INTEGER   COMM, NEWCOMM, IERROR


C++ Syntax
       #include <mpi.h>
       Intracomm Intracomm::Dup() const

       Intercomm Intercomm::Dup() const


INPUT PARAMETER
       comm      Communicator (handle).


OUTPUT PARAMETERS
       newcomm   Copy of comm (handle).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       MPI_Comm_dup  duplicates  the  existing  communicator  comm  with associated key values. For each key
       value, the respective copy callback function determines the attribute value associated with this  key
       in  the  new  communicator;  one  particular  action  that  a copy callback may take is to delete the
       attribute from the new communicator. Returns in newcomm a new communicator with the same  group,  any
       copied  cached  information, but a new context (see Section 5.7.1 of the MPI-1 Standard, "Functional-ity"). "Functionality").
       ity").


NOTES
       This operation is used to provide a parallel library call with a duplicate communication  space  that
       has  the  same  properties as the original communicator. This includes any attributes (see below) and
       topologies (see Chapter 6, "Process Topologies," in the MPI-1 Standard). This call is valid  even  if
       there are pending point-to-point communications involving the communicator comm. A typical call might
       involve an MPI_Comm_dup at the beginning of the parallel call, and an MPI_Comm_free  of  that  dupli-cated duplicated
       cated communicator at the end of the call. Other models of communicator management are also possible.

       This call applies to both intra- and intercommunicators.


ERRORS
       Almost all MPI routines return an error value; C routines as the value of the  function  and  Fortran
       routines  in  the  last argument. C++ functions do not return errors. If the default error handler is
       set to MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism will be used to  throw
       an MPI:Exception object.

       Before  the  error value is returned, the current MPI error handler is called. By default, this error
       handler aborts the MPI job, except for I/O function errors. The error handler  may  be  changed  with
       MPI_Comm_set_errhandler;  the  predefined  error handler MPI_ERRORS_RETURN may be used to cause error
       values to be returned. Note that MPI does not guarantee that an MPI  program  can  continue  past  an
       error.





Open MPI 1.2                                   September 2006                         MPI_Comm_dup(3OpenMPI)