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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