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