docs(best_practices): add information about the packaging of a cmake project

documentation/best_practices/cmake.rst

@@ -0,0 +1,94 @@
+***************************
+CMake with Bitbake recipes
+***************************
+
+Example of using CMake with Bitbake recipes. 
+
+Please find the example here:
+`CMake Yocto Example <https://bitbucket.gad.local/projects/ICO/repos/coreos/browse/layers/meta-belden-coreos/recipes-demo/cmake-demo?at=refs%2Fheads%2Fdoc_demo_cmake_yocto>`_.
+
+
+BitBake recipe
+===============
+
+Bitbake recipe inherits the cmake class and then ``CMakeLists.txt`` file can be used for building and installing.
+``CMakeLists.txt`` is expected at top of the sources tree pointed by ``SRC_URI``. 
+Usually this file is fetched using git or by downloading a tarball (.tar.gz).
+If this file is created locally it should be placed somewhere in path (usually ``<Package Name>/files``). Files that are going to be used in 
+package need to be included using ``SRC_URI +=``, files need to be included with paths relative to files directory.
+Installation of generated files can also be done using native CMake install command (which is recommended), 
+but in case something specific is needed, developer can override CMake installation with a BitBake ``do_install`` function.
+
+.. warning::
+   When using CMake for installation of some files, and using Bitbake recipe 
+   for installing other files. Bitbake's ``do_install`` will override the CMake 
+   installation, therefore, one should use ``do_install:append``.
+
+
+
+``CMakeLists.txt`` file
+========================
+When building binaries and libraries in the same package, it's a good idea to keep ``CMakeLists.txt`` 
+files split up over all source directories with top ``CMakeLists.txt`` to keep common info:
+
+* ``cmake_minimum_required`` - Defines minimum version of CMake required for desired build. Please check what version is supported by installed Yocto.
+* ``project`` - Defines project name and version.
+* ``add_subdirectory`` - If the package uses multiple ``CMakeLists.txt`` files, their directories should be included using this command.
+
+optional: ``set(CMAKE_VERBOSE_MAKEFILE ON)`` - can be used for debugging
+
+
+
+Helloworld - Simple binary example
+===================================
+
+This method shows a simple "Hello world" program written in C, 
+that uses CMake for building and installing the binary in Yocto.
+
+Additional information about this topic can be found in official 
+documentation: :external:ref:`Yocto Project - CMake
+<ref-classes-cmake>`. 
+
+
+
+CMake file - explanation
+-------------------------
+``CMakeLists.txt`` inherits top ``CMakeLists.txt``, so only minimal information is defined in this file:
+
+* ``add_executable`` - Creating binary file
+* ``install`` - Installing binary file
+
+
+
+
+Hello service - Simple binary is started in systemd
+====================================================
+
+A simple service that starts binary on boot is created. Service 
+file is installed using Bitbake method, as using CMake can be 
+avoided in this case (no need to build).
+
+
+
+
+Libdemo - Simple library example
+=================================
+
+Demo library with one function is built and installed using CMake.
+An include file is also installed.
+
+Further information about building different types of libraries can 
+be found on official CMake page: :external:ref:`Yocto Project Library documentation 
+<dev-manual/common-tasks:working with libraries>`.
+
+
+
+CMake file - explanation
+-------------------------
+
+``CMakeLists.txt`` inherits top ``CMakeLists.txt``, but this ``CMakeLists.txt`` is somewhat different compared to Helloworld:
+
+* ``add_library`` - declare the library target.
+* ``set_target_properties`` - define different properties that are useful for creating library (e.g. defining include files)
+* ``set_target_properties`` - installing files to desired locations
+

documentation/best_practices/index.rst

@@ -0,0 +1,13 @@
+
+==============================
+Belden CoreOS Best Practices
+==============================
+
+|
+
+.. toctree::
+   :caption: Table of Contents
+   :numbered:
+
+   overview
+   cmake

documentation/best_practices/overview.rst

@@ -0,0 +1,6 @@
+************************
+Best Practices Overview
+************************
+
+To ease the support and developement of CoreOS on multiple plateform,
+some examples were made to show developers good practices when working with yocto.

documentation/index.rst

@@ -32,6 +32,7 @@ same structures.
 
    Reference Manual <ref-manual/index>
    Boot Concepts <boot/index>
+   Best Practices <best_practices/index>
 
 .. toctree::
    :maxdepth: 1

documentation/ref-manual/classes.rst

@@ -13,7 +13,7 @@ provided by OpenEmbedded-Core are documented in the
 ``coreos-efi-secureboot.bbclass``
 =================================
 
-The ``coreos-efi-secureboot`` class is a class made to be ihnerited in a global
+The ``coreos-efi-secureboot`` class is a class made to be inherited in a global
 configuration file. On the CoreOS distribution, this class is inherited inside
 the CoreOS distrubtion configuration file.