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.. _mpi_comm_get_parent:
MPI_Comm_get_parent
===================
.. include_body
:ref:`MPI_Comm_get_parent` |mdash| Returns the parent intercommunicator of
current spawned process.
SYNTAX
------
C Syntax
^^^^^^^^
.. code-block:: c
#include <mpi.h>
int MPI_Comm_get_parent(MPI_Comm *parent)
Fortran Syntax
^^^^^^^^^^^^^^
.. code-block:: fortran
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_COMM_GET_PARENT(PARENT, IERROR)
INTEGER PARENT, IERROR
Fortran 2008 Syntax
^^^^^^^^^^^^^^^^^^^
.. code-block:: fortran
USE mpi_f08
MPI_Comm_get_parent(parent, ierror)
TYPE(MPI_Comm), INTENT(OUT) :: parent
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
OUTPUT PARAMETERS
-----------------
* ``parent``: The parent communicator (handle).
* ``ierror``: Fortran only: Error status (integer).
DESCRIPTION
-----------
If a process was started with :ref:`MPI_Comm_spawn` or :ref:`MPI_Comm_spawn_multiple`,
:ref:`MPI_Comm_get_parent` returns the "parent" intercommunicator of the
current process. This parent intercommunicator is created implicitly
inside of :ref:`MPI_Init` and is the same intercommunicator returned by the
spawn call made in the parents.
If the process was not spawned, :ref:`MPI_Comm_get_parent` returns
MPI_COMM_NULL.
After the parent communicator is freed or disconnected,
:ref:`MPI_Comm_get_parent` returns MPI_COMM_NULL.
NOTES
-----
:ref:`MPI_Comm_get_parent` returns a handle to a single intercommunicator.
Calling :ref:`MPI_Comm_get_parent` a second time returns a handle to the same
intercommunicator. Freeing the handle with :ref:`MPI_Comm_disconnect` or
:ref:`MPI_Comm_free` will cause other references to the intercommunicator to
become invalid (dangling). Note that calling :ref:`MPI_Comm_free` on the parent
communicator is not useful.
ERRORS
------
.. include:: ./ERRORS.rst
.. seealso::
* :ref:`MPI_Comm_spawn`
* :ref:`MPI_Comm_spawn_multiple`
|
