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.. _mpi_comm_set_name:
MPI_Comm_set_name
=================
.. include_body
:ref:`MPI_Comm_set_name` |mdash| Associates a name with a communicator.
SYNTAX
------
C Syntax
^^^^^^^^
.. code-block:: c
#include <mpi.h>
int MPI_Comm_set_name(MPI_Comm comm, const char *comm_name)
Fortran Syntax
^^^^^^^^^^^^^^
.. code-block:: fortran
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
^^^^^^^^^^^^^^^^^^^
.. code-block:: fortran
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
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
-----------
:ref:`MPI_Comm_set_name` allows a user to associate a name string with a
communicator. The character string that is passed to :ref:`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.
:ref:`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
:ref:`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 (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 :ref:`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
------
.. include:: ./ERRORS.rst
.. seealso::
* :ref:`MPI_Comm_get_name`
|
