.. _mpi_info_get_nthkey:


MPI_Info_get_nthkey
===================

.. include_body

:ref:`MPI_Info_get_nthkey` |mdash| Returns the *n*\ th defined key in *info*.


SYNTAX
------


C Syntax
^^^^^^^^

.. code-block:: c

   #include <mpi.h>

   int MPI_Info_get_nthkey(MPI_Info info, int n, char *key)


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

.. code-block:: fortran

   USE MPI
   ! or the older form: INCLUDE 'mpif.h'
   MPI_INFO_GET_NTHKEY(INFO, N, KEY, IERROR)
   	INTEGER		INFO, N, IERROR
   	CHARACTER*(*)	KEY


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

.. code-block:: fortran

   USE mpi_f08
   MPI_Info_get_nthkey(info, n, key, ierror)
   	TYPE(MPI_Info), INTENT(IN) :: info
   	INTEGER, INTENT(IN) :: n
   	CHARACTER(LEN=*), INTENT(OUT) :: key
   	INTEGER, OPTIONAL, INTENT(OUT) :: ierror


INPUT PARAMETERS
----------------
* ``info``: Info object (handle).
* ``n``: Key number (integer).

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

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

:ref:`MPI_Info_get_nthkey` returns the *n*\ th defined key in *info*. Keys are
numbered 0...\ *N* - 1 where *N* is the value returned by
:ref:`MPI_Info_get_nkeys`. All keys between 0 and *N* - 1 are guaranteed to be
defined. The number of a given key does not change as long as *info* is
not modified with :ref:`MPI_Info_set` or :ref:`MPI_Info_delete`.


ERRORS
------

.. include:: ./ERRORS.rst

.. seealso::
   * :ref:`MPI_Info_get`
   * :ref:`MPI_Info_get_nkeys`
   * :ref:`MPI_Info_get_valuelen`