doc: application: improvements to "Overriding Default Configuration"

For information on available kernel configuration options, including

inter-dependencies between options, see the :ref:`configuration`.

.. _application_set_conf:

Setting Application Configuration Values

========================================

Overriding Default Configuration

================================

Override the default board and kernel configuration to temporarily alter the

application's configuration, perhaps to test the effect of a change.

Follow these steps to override an application's configuration

temporarily, perhaps to test the effect of a change.

.. note::

   If you want to permanently alter the configuration you

   should revise the :file:`.conf` file.

   If you want to permanently alter the configuration you should set

   the new value in a :file:`.conf` file, as described above in

   :ref:`application_set_conf`.

The steps below describe how to configure your application using a

menu-driven configurator interface. While you can edit your

application's :file:`.config` manually, using a configurator tool is

preferred, since it correctly handles dependencies between options.

#. Generate a Ninja build system, and use it to run ``ninja

   menuconfig`` as follows.

Configure the kernel options using a menu-driven interface. While you can add

entries manually, using the configuration menu is a preferred method.

   a) Using CMake, create a build directory (:file:`~/app/build`) from

      your application directory (:file:`~/app`) with a Ninja build

      system.

      For example, on a Unix shell:

#. After generating project files run :command:`ninja menuconfig` to launch the menu-driven interface.

      .. code-block:: bash

         $ cd ~/app

         $ mkdir build && cd build

         $ cmake -GNinja ..

   a) In a terminal session, navigate to the application directory

      (:file:`~/app`).

   b) Run ``ninja menuconfig`` from the build directory

      (:file:`~/app/build`).

   b) Enter the following command:

      Continuing the above Unix shell example:

      .. code-block:: bash

          $ cmake -Bbuild -H. -GNinja

          $ ninja -C build menuconfig

          $ ninja menuconfig

      A question-based menu opens that allows you to set individual configuration

      options.

      A question-based menu opens that allows you to set individual

      configuration options.

      .. image:: figures/app_kernel_conf_1.png

           :width: 600px

   * Type a numerical value in the round brackets :guilabel:`( )`.

   * Press :kbd:`Tab` to navigate the command menu at the bottom of the display.

   * Press :kbd:`Tab` to navigate the command menu at the bottom of the

     display.

     .. note::

   Press :kbd:`Enter` to return to the menu.

#. Press :kbd:`/` to bring up a search menu to look for a particular option.

#. After configuring the kernel options for your application, tab to

   :guilabel:`< Save >` and press :kbd:`Enter`.