MPI_Comm_set_name(3)               Open MPI               MPI_Comm_set_name(3)



NAME
       MPI_Comm_set_name - Associates a name with a communicator.


SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Comm_set_name(MPI_Comm comm, char *comm_name)


Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_COMM_SET_NAME(COMM, COMM_NAME, IERROR)
            INTEGER   COMM, IERROR
            CHARACTER*(*) COMM_NAME


C++ Syntax
       #include <mpi.h>
       void MPI::Comm::Set_name(const char* comm_name)


INPUT/OUTPUT PARAMETER
       comm      Communicator whose identifier is to be set (handle).


INPUT PARAMETER
       comm_name Character string to be used as the identifier for the
                 communicator (string).


OUTPUT PARAMETER
       IERROR    Fortran only: Error status (integer).



DESCRIPTION
       MPI_Comm_set_name allows a user to associate a name string with a
       communicator. The character string that is passed to MPI_Comm_set_name
       is saved inside the MPI library (so it can be freed by the caller
       immediately after the call, or allocated on the stack). Leading spaces
       in name are significant, but trailing ones are not.

       MPI_Comm_set_name is a local (noncollective) operation, which affects
       only the name of the communicator as seen in the process that made the
       MPI_Comm_set_name call. There is no requirement that the same (or any)
       name be assigned to a communicator in every process where it exists.

       The length of the name that can be stored is limited to the value of
       MPI_MAX_OBJECT_NAME in Fortran and MPI_MAX_OBJECT_NAME-1 in C and C++
       (to allow for the null terminator). Attempts to set names longer than
       this will result in truncation of the name. MPI_MAX_OBJECT_NAME must
       have a value of at least 64.



NOTES
       Since MPI_Comm_set_name is provided to help debug code, it is sensible
       to give the same name to a communicator in all of the processes where
       it exists, to avoid confusion.

       Regarding name length, under circumstances of store exhaustion, an
       attempt to set a name of any length could fail; therefore, the value of
       MPI_MAX_OBJECT_NAME should be viewed only as a strict upper bound on
       the name length, not a guarantee that setting names of less than this
       length will always succeed.


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.


SEE ALSO
       MPI_Comm_get_name






1.4.1                            Jan 14, 2010             MPI_Comm_set_name(3)
