.. _mpi_win_post:


MPI_Win_post
============

.. include_body

:ref:`MPI_Win_post` |mdash| Starts an RMA exposure epoch for the local window
associated with *win*


SYNTAX
------


C Syntax
^^^^^^^^

.. code-block:: c

   #include <mpi.h>

   int MPI_Win_post(MPI_Group group, int assert, MPI_Win win)


Fortran Syntax
^^^^^^^^^^^^^^

.. code-block:: fortran

   USE MPI
   ! or the older form: INCLUDE 'mpif.h'
   MPI_WIN_POST(GROUP, ASSERT, WIN, IERROR)
   	INTEGER GROUP, ASSERT, WIN, IERROR


Fortran 2008 Syntax
^^^^^^^^^^^^^^^^^^^

.. code-block:: fortran

   USE mpi_f08
   MPI_Win_post(group, assert, win, ierror)
   	TYPE(MPI_Group), INTENT(IN) :: group
   	INTEGER, INTENT(IN) :: assert
   	TYPE(MPI_Win), INTENT(IN) :: win
   	INTEGER, OPTIONAL, INTENT(OUT) :: ierror


INPUT PARAMETERS
----------------
* ``group``: The group of origin processes (handle)
* ``assert``: Program assertion (integer)
* ``win``: Window object (handle)

OUTPUT PARAMETERS
-----------------
* ``ierror``: Fortran only: Error status (integer).

DESCRIPTION
-----------

Starts an RMA exposure epoch for the local window associated with *win*.
Only the processes belonging to *group* should access the window with
RMA calls on *win* during this epoch. Each process in *group* must issue
a matching call to :ref:`MPI_Win_start`. :ref:`MPI_Win_post` does not block.

The *assert* argument is used to provide assertions on the context of

the call that may be used for various optimizations. A value of *assert*
^ 0 is always valid. The following assertion values are supported:

MPI_MODE_NOCHECK
   The matching calls to :ref:`MPI_Win_start` have not yet occurred on any
   origin processes when this call is made. This assertion must be
   present for all matching :ref:`MPI_Win_start` calls if used.

MPI_MODE_NOSTORE
   Informs that the local window was not updated by local stores or get
   calls in the preceding epoch.

MPI_MODE_NOPUT
   Informs that the local window will not be updated by put or
   accummulate calls until the ensuing wait synchronization.


ERRORS
------

.. include:: ./ERRORS.rst

.. seealso::
   * :ref:`MPI_Win_start`
   * :ref:`MPI_Win_wait`