+
+Integrating with the Build System
+---------------------------------
+
+DPDK is built using the tools ``meson`` and ``ninja``.
+
+Therefore all new component additions should include a ``meson.build`` file,
+and should be added to the component lists in the ``meson.build`` files in the
+relevant top-level directory:
+either ``lib`` directory or a ``driver`` subdirectory.
+
+Meson Build File Contents - Libraries
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The ``meson.build`` file for a new DPDK library should be of the following basic
+format.
+
+.. code-block:: python
+
+ sources = files('file1.c', ...)
+ headers = files('file1.h', ...)
+
+
+This will build based on a number of conventions and assumptions within the DPDK
+itself, for example, that the library name is the same as the directory name in
+which the files are stored.
+
+For a library ``meson.build`` file, there are number of variables which can be
+set, some mandatory, others optional. The mandatory fields are:
+
+sources
+ **Default Value = []**.
+ This variable should list out the files to be compiled up to create the
+ library. Files must be specified using the meson ``files()`` function.
+
+
+The optional fields are:
+
+build
+ **Default Value = true**
+ Used to optionally compile a library, based on its dependencies or
+ environment. When set to "false" the ``reason`` value, explained below, should
+ also be set to explain to the user why the component is not being built.
+ A simple example of use would be:
+
+.. code-block:: python
+
+ if not is_linux
+ build = false
+ reason = 'only supported on Linux'
+ endif
+
+
+cflags
+ **Default Value = [<-march/-mcpu flags>]**.
+ Used to specify any additional cflags that need to be passed to compile
+ the sources in the library.
+
+deps
+ **Default Value = ['eal']**.
+ Used to list the internal library dependencies of the library. It should
+ be assigned to using ``+=`` rather than overwriting using ``=``. The
+ dependencies should be specified as strings, each one giving the name of
+ a DPDK library, without the ``librte_`` prefix. Dependencies are handled
+ recursively, so specifying e.g. ``mempool``, will automatically also
+ make the library depend upon the mempool library's dependencies too -
+ ``ring`` and ``eal``. For libraries that only depend upon EAL, this
+ variable may be omitted from the ``meson.build`` file. For example:
+
+.. code-block:: python
+
+ deps += ['ethdev']
+
+
+ext_deps
+ **Default Value = []**.
+ Used to specify external dependencies of this library. They should be
+ returned as dependency objects, as returned from the meson
+ ``dependency()`` or ``find_library()`` functions. Before returning
+ these, they should be checked to ensure the dependencies have been
+ found, and, if not, the ``build`` variable should be set to ``false``.
+ For example:
+
+.. code-block:: python
+
+ my_dep = dependency('libX', required: 'false')
+ if my_dep.found()
+ ext_deps += my_dep
+ else
+ build = false
+ endif
+
+
+headers
+ **Default Value = []**.
+ Used to return the list of header files for the library that should be
+ installed to $PREFIX/include when ``ninja install`` is run. As with
+ source files, these should be specified using the meson ``files()``
+ function.
+ When ``check_includes`` build option is set to ``true``, each header file
+ has additional checks performed on it, for example to ensure that it is
+ not missing any include statements for dependent headers.
+ For header files which are public, but only included indirectly in
+ applications, these checks can be skipped by using the ``indirect_headers``
+ variable rather than ``headers``.
+
+indirect_headers
+ **Default Value = []**.
+ As with ``headers`` option above, except that the files are not checked
+ for all needed include files as part of a DPDK build when
+ ``check_includes`` is set to ``true``.
+
+includes:
+ **Default Value = []**.
+ Used to indicate any additional header file paths which should be
+ added to the header search path for other libs depending on this
+ library. EAL uses this so that other libraries building against it
+ can find the headers in subdirectories of the main EAL directory. The
+ base directory of each library is always given in the include path,
+ it does not need to be specified here.
+
+name
+ **Default Value = library name derived from the directory name**.
+ If a library's .so or .a file differs from that given in the directory
+ name, the name should be specified using this variable. In practice,
+ since the convention is that for a library called ``librte_xyz.so``, the
+ sources are stored in a directory ``lib/librte_xyz``, this value should
+ never be needed for new libraries.
+
+.. note::
+
+ The name value also provides the name used to find the function version
+ map file, as part of the build process, so if the directory name and
+ library names differ, the ``version.map`` file should be named
+ consistently with the library, not the directory
+
+objs
+ **Default Value = []**.
+ This variable can be used to pass to the library build some pre-built
+ objects that were compiled up as part of another target given in the
+ included library ``meson.build`` file.
+
+reason
+ **Default Value = '<unknown reason>'**.
+ This variable should be used when a library is not to be built i.e. when
+ ``build`` is set to "false", to specify the reason why a library will not be
+ built. For missing dependencies this should be of the form
+ ``'missing dependency, "libname"'``.
+
+use_function_versioning
+ **Default Value = false**.
+ Specifies if the library in question has ABI versioned functions. If it
+ has, this value should be set to ensure that the C files are compiled
+ twice with suitable parameters for each of shared or static library
+ builds.
+
+Meson Build File Contents - Drivers
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+For drivers, the values are largely the same as for libraries. The variables
+supported are:
+
+build
+ As above.
+
+cflags
+ As above.
+
+deps
+ As above.
+
+ext_deps
+ As above.
+
+includes
+ **Default Value = <driver directory>** Some drivers include a base
+ directory for additional source files and headers, so we have this
+ variable to allow the headers from that base directory to be found when
+ compiling driver sources. Should be appended to using ``+=`` rather than
+ overwritten using ``=``. The values appended should be meson include
+ objects got using the ``include_directories()`` function. For example:
+
+.. code-block:: python
+
+ includes += include_directories('base')
+
+name
+ As above, though note that each driver class can define it's own naming
+ scheme for the resulting ``.so`` files.
+
+objs
+ As above, generally used for the contents of the ``base`` directory.
+
+pkgconfig_extra_libs
+ **Default Value = []**
+ This variable is used to pass additional library link flags through to
+ the DPDK pkgconfig file generated, for example, to track any additional
+ libraries that may need to be linked into the build - especially when
+ using static libraries. Anything added here will be appended to the end
+ of the ``pkgconfig --libs`` output.
+
+reason
+ As above.
+
+sources [mandatory]
+ As above
+
+headers
+ As above
+
+version
+ As above