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, const char *comm_name)

Fortran Syntax

       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_COMM_SET_NAME(COMM, COMM_NAME, IERROR)
            INTEGER   COMM, IERROR
            CHARACTER*(*) COMM_NAME

Fortran 2008 Syntax

       USE mpi_f08
       MPI_Comm_set_name(comm, comm_name, ierror)
            TYPE(MPI_Comm), INTENT(IN) :: comm
            CHARACTER(LEN=*), INTENT(IN) :: comm_name
            INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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

4.1.6                                             Sep 30, 2023                              MPI_Comm_set_name(3)