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+******************
+Variables Glossary
+******************
+This chapter lists common variables used in the OpenEmbedded build
+system and gives an overview of their function and contents.
+`A <#var-ABIEXTENSION>`__ `B <#var-B>`__ `C <#var-CACHE>`__
+`D <#var-D>`__ `E <#var-EFI_PROVIDER>`__ `F <#var-FEATURE_PACKAGES>`__
+`G <#var-GCCPIE>`__ `H <#var-HOMEPAGE>`__ `I <#var-ICECC_DISABLED>`__
+`K <#var-KARCH>`__ `L <#var-LABELS>`__ `M <#var-MACHINE>`__
+`N <#var-NATIVELSBSTRING>`__ `O <#var-OBJCOPY>`__ `P <#var-P>`__
+`R <#var-RANLIB>`__ `S <#var-S>`__ `T <#var-T>`__
+`U <#var-UBOOT_CONFIG>`__ `V <#var-VOLATILE_LOG_DIR>`__
+`W <#var-WARN_QA>`__ `X <#var-XSERVER>`__
+ABIEXTENSION
+   Extension to the Application Binary Interface (ABI) field of the GNU
+   canonical architecture name (e.g. "eabi").
+   ABI extensions are set in the machine include files. For example, the
+   ``meta/conf/machine/include/arm/arch-arm.inc`` file sets the
+   following extension: ABIEXTENSION = "eabi"
+ALLOW_EMPTY
+   Specifies whether to produce an output package even if it is empty.
+   By default, BitBake does not produce empty packages. This default
+   behavior can cause issues when there is an
+   ```RDEPENDS`` <#var-RDEPENDS>`__ or some other hard runtime
+   requirement on the existence of the package.
+   Like all package-controlling variables, you must always use them in
+   conjunction with a package name override, as in: ALLOW_EMPTY_${PN} =
+   "1" ALLOW_EMPTY_${PN}-dev = "1" ALLOW_EMPTY_${PN}-staticdev = "1"
+ALTERNATIVE
+   Lists commands in a package that need an alternative binary naming
+   scheme. Sometimes the same command is provided in multiple packages.
+   When this occurs, the OpenEmbedded build system needs to use the
+   alternatives system to create a different binary naming scheme so the
+   commands can co-exist.
+   To use the variable, list out the package's commands that also exist
+   as part of another package. For example, if the ``busybox`` package
+   has four commands that also exist as part of another package, you
+   identify them as follows: ALTERNATIVE_busybox = "sh sed test bracket"
+   For more information on the alternatives system, see the
+   "```update-alternatives.bbclass`` <#ref-classes-update-alternatives>`__"
+   section.
+ALTERNATIVE_LINK_NAME
+   Used by the alternatives system to map duplicated commands to actual
+   locations. For example, if the ``bracket`` command provided by the
+   ``busybox`` package is duplicated through another package, you must
+   use the ``ALTERNATIVE_LINK_NAME`` variable to specify the actual
+   location: ALTERNATIVE_LINK_NAME[bracket] = "/usr/bin/["
+   In this example, the binary for the ``bracket`` command (i.e. ``[``)
+   from the ``busybox`` package resides in ``/usr/bin/``.
+   .. note::
+      If
+      ALTERNATIVE_LINK_NAME
+      is not defined, it defaults to
+      ${bindir}/
+      name
+      .
+   For more information on the alternatives system, see the
+   "```update-alternatives.bbclass`` <#ref-classes-update-alternatives>`__"
+   section.
+ALTERNATIVE_PRIORITY
+   Used by the alternatives system to create default priorities for
+   duplicated commands. You can use the variable to create a single
+   default regardless of the command name or package, a default for
+   specific duplicated commands regardless of the package, or a default
+   for specific commands tied to particular packages. Here are the
+   available syntax forms: ALTERNATIVE_PRIORITY = "priority"
+   ALTERNATIVE_PRIORITY[name] = "priority"
+   ALTERNATIVE_PRIORITY_pkg[name] = "priority"
+   For more information on the alternatives system, see the
+   "```update-alternatives.bbclass`` <#ref-classes-update-alternatives>`__"
+   section.
+ALTERNATIVE_TARGET
+   Used by the alternatives system to create default link locations for
+   duplicated commands. You can use the variable to create a single
+   default location for all duplicated commands regardless of the
+   command name or package, a default for specific duplicated commands
+   regardless of the package, or a default for specific commands tied to
+   particular packages. Here are the available syntax forms:
+   ALTERNATIVE_TARGET = "target" ALTERNATIVE_TARGET[name] = "target"
+   ALTERNATIVE_TARGET_pkg[name] = "target"
+   .. note::
+      If ``ALTERNATIVE_TARGET`` is not defined, it inherits the value
+      from the
+      ```ALTERNATIVE_LINK_NAME`` <#var-ALTERNATIVE_LINK_NAME>`__
+      variable.
+      If ``ALTERNATIVE_LINK_NAME`` and ``ALTERNATIVE_TARGET`` are the
+      same, the target for ``ALTERNATIVE_TARGET`` has "``.{BPN}``"
+      appended to it.
+      Finally, if the file referenced has not been renamed, the
+      alternatives system will rename it to avoid the need to rename
+      alternative files in the ```do_install`` <#ref-tasks-install>`__
+      task while retaining support for the command if necessary.
+   For more information on the alternatives system, see the
+   "```update-alternatives.bbclass`` <#ref-classes-update-alternatives>`__"
+   section.
+APPEND
+   An override list of append strings for each target specified with
+   ```LABELS`` <#var-LABELS>`__.
+   See the ```grub-efi`` <#ref-classes-grub-efi>`__ class for more
+   information on how this variable is used.
+AR
+   The minimal command and arguments used to run ``ar``.
+ARCHIVER_MODE
+   When used with the ```archiver`` <#ref-classes-archiver>`__ class,
+   determines the type of information used to create a released archive.
+   You can use this variable to create archives of patched source,
+   original source, configured source, and so forth by employing the
+   following variable flags (varflags): ARCHIVER_MODE[src] = "original"
+   # Uses original (unpacked) source # files. ARCHIVER_MODE[src] =
+   "patched" # Uses patched source files. This is # the default.
+   ARCHIVER_MODE[src] = "configured" # Uses configured source files.
+   ARCHIVER_MODE[diff] = "1" # Uses patches between do_unpack and #
+   do_patch. ARCHIVER_MODE[diff-exclude] ?= "file file ..." # Lists
+   files and directories to # exclude from diff. ARCHIVER_MODE[dumpdata]
+   = "1" # Uses environment data. ARCHIVER_MODE[recipe] = "1" # Uses
+   recipe and include files. ARCHIVER_MODE[srpm] = "1" # Uses RPM
+   package files. For information on how the variable works, see the
+   ``meta/classes/archiver.bbclass`` file in the `Source
+   Directory <#source-directory>`__.
+AS
+   Minimal command and arguments needed to run the assembler.
+ASSUME_PROVIDED
+   Lists recipe names (```PN`` <#var-PN>`__ values) BitBake does not
+   attempt to build. Instead, BitBake assumes these recipes have already
+   been built.
+   In OpenEmbedded-Core, ``ASSUME_PROVIDED`` mostly specifies native
+   tools that should not be built. An example is ``git-native``, which
+   when specified, allows for the Git binary from the host to be used
+   rather than building ``git-native``.
+ASSUME_SHLIBS
+   Provides additional ``shlibs`` provider mapping information, which
+   adds to or overwrites the information provided automatically by the
+   system. Separate multiple entries using spaces.
+   As an example, use the following form to add an ``shlib`` provider of
+   shlibname in packagename with the optional version:
+   shlibname:packagename[_version]
+   Here is an example that adds a shared library named ``libEGL.so.1``
+   as being provided by the ``libegl-implementation`` package:
+   ASSUME_SHLIBS = "libEGL.so.1:libegl-implementation"
+AUTHOR
+   The email address used to contact the original author or authors in
+   order to send patches and forward bugs.
+AUTO_LIBNAME_PKGS
+   When the ```debian`` <#ref-classes-debian>`__ class is inherited,
+   which is the default behavior, ``AUTO_LIBNAME_PKGS`` specifies which
+   packages should be checked for libraries and renamed according to
+   Debian library package naming.
+   The default value is "${PACKAGES}", which causes the debian class to
+   act on all packages that are explicitly generated by the recipe.
+AUTO_SYSLINUXMENU
+   Enables creating an automatic menu for the syslinux bootloader. You
+   must set this variable in your recipe. The
+   ```syslinux`` <#ref-classes-syslinux>`__ class checks this variable.
+AUTOREV
+   When ``SRCREV`` is set to the value of this variable, it specifies to
+   use the latest source revision in the repository. Here is an example:
+   SRCREV = "${AUTOREV}"
+   If you use the previous statement to retrieve the latest version of
+   software, you need to be sure ```PV`` <#var-PV>`__ contains
+   ``${``\ ```SRCPV`` <#var-SRCPV>`__\ ``}``. For example, suppose you
+   have a kernel recipe that inherits the
+   `kernel <#ref-classes-kernel>`__ class and you use the previous
+   statement. In this example, ``${SRCPV}`` does not automatically get
+   into ``PV``. Consequently, you need to change ``PV`` in your recipe
+   so that it does contain ``${SRCPV}``.
+   For more information see the "`Automatically Incrementing a Binary
+   Package Revision
+   Number <&YOCTO_DOCS_DEV_URL;#automatically-incrementing-a-binary-package-revision-number>`__"
+   section in the Yocto Project Development Tasks Manual.
+AVAILABLE_LICENSES
+   List of licenses found in the directories specified by
+   ```COMMON_LICENSE_DIR`` <#var-COMMON_LICENSE_DIR>`__ and
+   ```LICENSE_PATH`` <#var-LICENSE_PATH>`__.
+   .. note::
+      It is assumed that all changes to
+      COMMON_LICENSE_DIR
+      and
+      LICENSE_PATH
+      have been done before
+      AVAILABLE_LICENSES
+      is defined (in
+      license.bbclass
+      ).
+AVAILTUNES
+   The list of defined CPU and Application Binary Interface (ABI)
+   tunings (i.e. "tunes") available for use by the OpenEmbedded build
+   system.
+   The list simply presents the tunes that are available. Not all tunes
+   may be compatible with a particular machine configuration, or with
+   each other in a
+   `Multilib <&YOCTO_DOCS_DEV_URL;#combining-multiple-versions-library-files-into-one-image>`__
+   configuration.
+   To add a tune to the list, be sure to append it with spaces using the
+   "+=" BitBake operator. Do not simply replace the list by using the
+   "=" operator. See the "`Basic
+   Syntax <&YOCTO_DOCS_BB_URL;#basic-syntax>`__" section in the BitBake
+   User Manual for more information.
+B
+   The directory within the `Build Directory <#build-directory>`__ in
+   which the OpenEmbedded build system places generated objects during a
+   recipe's build process. By default, this directory is the same as the
+   ```S`` <#var-S>`__ directory, which is defined as: S =
+   "${WORKDIR}/${BP}"
+   You can separate the (``S``) directory and the directory pointed to
+   by the ``B`` variable. Most Autotools-based recipes support
+   separating these directories. The build system defaults to using
+   separate directories for ``gcc`` and some kernel recipes.
+BAD_RECOMMENDATIONS
+   Lists "recommended-only" packages to not install. Recommended-only
+   packages are packages installed only through the
+   ```RRECOMMENDS`` <#var-RRECOMMENDS>`__ variable. You can prevent any
+   of these "recommended" packages from being installed by listing them
+   with the ``BAD_RECOMMENDATIONS`` variable: BAD_RECOMMENDATIONS =
+   "package_name package_name package_name ..."
+   You can set this variable globally in your ``local.conf`` file or you
+   can attach it to a specific image recipe by using the recipe name
+   override: BAD_RECOMMENDATIONS_pn-target_image = "package_name"
+   It is important to realize that if you choose to not install packages
+   using this variable and some other packages are dependent on them
+   (i.e. listed in a recipe's ```RDEPENDS`` <#var-RDEPENDS>`__
+   variable), the OpenEmbedded build system ignores your request and
+   will install the packages to avoid dependency errors.
+   Support for this variable exists only when using the IPK and RPM
+   packaging backend. Support does not exist for DEB.
+   See the ```NO_RECOMMENDATIONS`` <#var-NO_RECOMMENDATIONS>`__ and the
+   ```PACKAGE_EXCLUDE`` <#var-PACKAGE_EXCLUDE>`__ variables for related
+   information.
+BASE_LIB
+   The library directory name for the CPU or Application Binary
+   Interface (ABI) tune. The ``BASE_LIB`` applies only in the Multilib
+   context. See the "`Combining Multiple Versions of Library Files into
+   One
+   Image <&YOCTO_DOCS_DEV_URL;#combining-multiple-versions-library-files-into-one-image>`__"
+   section in the Yocto Project Development Tasks Manual for information
+   on Multilib.
+   The ``BASE_LIB`` variable is defined in the machine include files in
+   the `Source Directory <#source-directory>`__. If Multilib is not
+   being used, the value defaults to "lib".
+BASE_WORKDIR
+   Points to the base of the work directory for all recipes. The default
+   value is "${TMPDIR}/work".
+BB_ALLOWED_NETWORKS
+   Specifies a space-delimited list of hosts that the fetcher is allowed
+   to use to obtain the required source code. Following are
+   considerations surrounding this variable:
+   -  This host list is only used if ``BB_NO_NETWORK`` is either not set
+      or set to "0".
+   -  Limited support for wildcard matching against the beginning of
+      host names exists. For example, the following setting matches
+      ``git.gnu.org``, ``ftp.gnu.org``, and ``foo.git.gnu.org``.
+      BB_ALLOWED_NETWORKS = "*.gnu.org"
+      .. note::
+         The use of the "``*``" character only works at the beginning of
+         a host name and it must be isolated from the remainder of the
+         host name. You cannot use the wildcard character in any other
+         location of the name or combined with the front part of the
+         name.
+         For example, ``*.foo.bar`` is supported, while ``*aa.foo.bar``
+         is not.
+   -  Mirrors not in the host list are skipped and logged in debug.
+   -  Attempts to access networks not in the host list cause a failure.
+   Using ``BB_ALLOWED_NETWORKS`` in conjunction with
+   ```PREMIRRORS`` <#var-PREMIRRORS>`__ is very useful. Adding the host
+   you want to use to ``PREMIRRORS`` results in the source code being
+   fetched from an allowed location and avoids raising an error when a
+   host that is not allowed is in a ```SRC_URI`` <#var-SRC_URI>`__
+   statement. This is because the fetcher does not attempt to use the
+   host listed in ``SRC_URI`` after a successful fetch from the
+   ``PREMIRRORS`` occurs.
+BB_DANGLINGAPPENDS_WARNONLY
+   Defines how BitBake handles situations where an append file
+   (``.bbappend``) has no corresponding recipe file (``.bb``). This
+   condition often occurs when layers get out of sync (e.g. ``oe-core``
+   bumps a recipe version and the old recipe no longer exists and the
+   other layer has not been updated to the new version of the recipe
+   yet).
+   The default fatal behavior is safest because it is the sane reaction
+   given something is out of sync. It is important to realize when your
+   changes are no longer being applied.
+   You can change the default behavior by setting this variable to "1",
+   "yes", or "true" in your ``local.conf`` file, which is located in the
+   `Build Directory <#build-directory>`__: Here is an example:
+   BB_DANGLINGAPPENDS_WARNONLY = "1"
+BB_DISKMON_DIRS
+   Monitors disk space and available inodes during the build and allows
+   you to control the build based on these parameters.
+   Disk space monitoring is disabled by default. To enable monitoring,
+   add the ``BB_DISKMON_DIRS`` variable to your ``conf/local.conf`` file
+   found in the `Build Directory <#build-directory>`__. Use the
+   following form: BB_DISKMON_DIRS = "action,dir,threshold [...]" where:
+   action is: ABORT: Immediately abort the build when a threshold is
+   broken. STOPTASKS: Stop the build after the currently executing tasks
+   have finished when a threshold is broken. WARN: Issue a warning but
+   continue the build when a threshold is broken. Subsequent warnings
+   are issued as defined by the BB_DISKMON_WARNINTERVAL variable, which
+   must be defined in the conf/local.conf file. dir is: Any directory
+   you choose. You can specify one or more directories to monitor by
+   separating the groupings with a space. If two directories are on the
+   same device, only the first directory is monitored. threshold is:
+   Either the minimum available disk space, the minimum number of free
+   inodes, or both. You must specify at least one. To omit one or the
+   other, simply omit the value. Specify the threshold using G, M, K for
+   Gbytes, Mbytes, and Kbytes, respectively. If you do not specify G, M,
+   or K, Kbytes is assumed by default. Do not use GB, MB, or KB.
+   Here are some examples: BB_DISKMON_DIRS = "ABORT,${TMPDIR},1G,100K
+   WARN,${SSTATE_DIR},1G,100K" BB_DISKMON_DIRS =
+   "STOPTASKS,${TMPDIR},1G" BB_DISKMON_DIRS = "ABORT,${TMPDIR},,100K"
+   The first example works only if you also provide the
+   ```BB_DISKMON_WARNINTERVAL`` <#var-BB_DISKMON_WARNINTERVAL>`__
+   variable in the ``conf/local.conf``. This example causes the build
+   system to immediately abort when either the disk space in
+   ``${TMPDIR}`` drops below 1 Gbyte or the available free inodes drops
+   below 100 Kbytes. Because two directories are provided with the
+   variable, the build system also issue a warning when the disk space
+   in the ``${SSTATE_DIR}`` directory drops below 1 Gbyte or the number
+   of free inodes drops below 100 Kbytes. Subsequent warnings are issued
+   during intervals as defined by the ``BB_DISKMON_WARNINTERVAL``
+   variable.
+   The second example stops the build after all currently executing
+   tasks complete when the minimum disk space in the ``${TMPDIR}``
+   directory drops below 1 Gbyte. No disk monitoring occurs for the free
+   inodes in this case.
+   The final example immediately aborts the build when the number of
+   free inodes in the ``${TMPDIR}`` directory drops below 100 Kbytes. No
+   disk space monitoring for the directory itself occurs in this case.
+BB_DISKMON_WARNINTERVAL
+   Defines the disk space and free inode warning intervals. To set these
+   intervals, define the variable in your ``conf/local.conf`` file in
+   the `Build Directory <#build-directory>`__.
+   If you are going to use the ``BB_DISKMON_WARNINTERVAL`` variable, you
+   must also use the ```BB_DISKMON_DIRS`` <#var-BB_DISKMON_DIRS>`__
+   variable and define its action as "WARN". During the build,
+   subsequent warnings are issued each time disk space or number of free
+   inodes further reduces by the respective interval.
+   If you do not provide a ``BB_DISKMON_WARNINTERVAL`` variable and you
+   do use ``BB_DISKMON_DIRS`` with the "WARN" action, the disk
+   monitoring interval defaults to the following:
+   BB_DISKMON_WARNINTERVAL = "50M,5K"
+   When specifying the variable in your configuration file, use the
+   following form: BB_DISKMON_WARNINTERVAL =
+   "disk_space_interval,disk_inode_interval" where: disk_space_interval
+   is: An interval of memory expressed in either G, M, or K for Gbytes,
+   Mbytes, or Kbytes, respectively. You cannot use GB, MB, or KB.
+   disk_inode_interval is: An interval of free inodes expressed in
+   either G, M, or K for Gbytes, Mbytes, or Kbytes, respectively. You
+   cannot use GB, MB, or KB.
+   Here is an example: BB_DISKMON_DIRS = "WARN,${SSTATE_DIR},1G,100K"
+   BB_DISKMON_WARNINTERVAL = "50M,5K" These variables cause the
+   OpenEmbedded build system to issue subsequent warnings each time the
+   available disk space further reduces by 50 Mbytes or the number of
+   free inodes further reduces by 5 Kbytes in the ``${SSTATE_DIR}``
+   directory. Subsequent warnings based on the interval occur each time
+   a respective interval is reached beyond the initial warning (i.e. 1
+   Gbytes and 100 Kbytes).
+BB_GENERATE_MIRROR_TARBALLS
+   Causes tarballs of the source control repositories (e.g. Git
+   repositories), including metadata, to be placed in the
+   ```DL_DIR`` <#var-DL_DIR>`__ directory.
+   For performance reasons, creating and placing tarballs of these
+   repositories is not the default action by the OpenEmbedded build
+   system. BB_GENERATE_MIRROR_TARBALLS = "1" Set this variable in your
+   ``local.conf`` file in the `Build Directory <#build-directory>`__.
+   Once you have the tarballs containing your source files, you can
+   clean up your ``DL_DIR`` directory by deleting any Git or other
+   source control work directories.
+BB_NUMBER_THREADS
+   The maximum number of tasks BitBake should run in parallel at any one
+   time. The OpenEmbedded build system automatically configures this
+   variable to be equal to the number of cores on the build system. For
+   example, a system with a dual core processor that also uses
+   hyper-threading causes the ``BB_NUMBER_THREADS`` variable to default
+   to "4".
+   For single socket systems (i.e. one CPU), you should not have to
+   override this variable to gain optimal parallelism during builds.
+   However, if you have very large systems that employ multiple physical
+   CPUs, you might want to make sure the ``BB_NUMBER_THREADS`` variable
+   is not set higher than "20".
+   For more information on speeding up builds, see the "`Speeding Up a
+   Build <&YOCTO_DOCS_DEV_URL;#speeding-up-a-build>`__" section in the
+   Yocto Project Development Tasks Manual.
+BB_SERVER_TIMEOUT
+   Specifies the time (in seconds) after which to unload the BitBake
+   server due to inactivity. Set ``BB_SERVER_TIMEOUT`` to determine how
+   long the BitBake server stays resident between invocations.
+   For example, the following statement in your ``local.conf`` file
+   instructs the server to be unloaded after 20 seconds of inactivity:
+   BB_SERVER_TIMEOUT = "20" If you want the server to never be unloaded,
+   set ``BB_SERVER_TIMEOUT`` to "-1".
+BBCLASSEXTEND
+   Allows you to extend a recipe so that it builds variants of the
+   software. Common variants for recipes exist such as "natives" like
+   ``quilt-native``, which is a copy of Quilt built to run on the build
+   system; "crosses" such as ``gcc-cross``, which is a compiler built to
+   run on the build machine but produces binaries that run on the target
+   ```MACHINE`` <#var-MACHINE>`__; "nativesdk", which targets the SDK
+   machine instead of ``MACHINE``; and "mulitlibs" in the form
+   "``multilib:``\ multilib_name".
+   To build a different variant of the recipe with a minimal amount of
+   code, it usually is as simple as adding the following to your recipe:
+   BBCLASSEXTEND =+ "native nativesdk" BBCLASSEXTEND =+
+   "multilib:multilib_name"
+   .. note::
+      Internally, the ``BBCLASSEXTEND`` mechanism generates recipe
+      variants by rewriting variable values and applying overrides such
+      as ``_class-native``. For example, to generate a native version of
+      a recipe, a ```DEPENDS`` <#var-DEPENDS>`__ on "foo" is rewritten
+      to a ``DEPENDS`` on "foo-native".
+      Even when using ``BBCLASSEXTEND``, the recipe is only parsed once.
+      Parsing once adds some limitations. For example, it is not
+      possible to include a different file depending on the variant,
+      since ``include`` statements are processed when the recipe is
+      parsed.
+BBFILE_COLLECTIONS
+   Lists the names of configured layers. These names are used to find
+   the other ``BBFILE_*`` variables. Typically, each layer will append
+   its name to this variable in its ``conf/layer.conf`` file.
+BBFILE_PATTERN
+   Variable that expands to match files from
+   ```BBFILES`` <#var-BBFILES>`__ in a particular layer. This variable
+   is used in the ``conf/layer.conf`` file and must be suffixed with the
+   name of the specific layer (e.g. ``BBFILE_PATTERN_emenlow``).
+BBFILE_PRIORITY
+   Assigns the priority for recipe files in each layer.
+   This variable is useful in situations where the same recipe appears
+   in more than one layer. Setting this variable allows you to
+   prioritize a layer against other layers that contain the same recipe
+   - effectively letting you control the precedence for the multiple
+   layers. The precedence established through this variable stands
+   regardless of a recipe's version (```PV`` <#var-PV>`__ variable). For
+   example, a layer that has a recipe with a higher ``PV`` value but for
+   which the ``BBFILE_PRIORITY`` is set to have a lower precedence still
+   has a lower precedence.
+   A larger value for the ``BBFILE_PRIORITY`` variable results in a
+   higher precedence. For example, the value 6 has a higher precedence
+   than the value 5. If not specified, the ``BBFILE_PRIORITY`` variable
+   is set based on layer dependencies (see the ``LAYERDEPENDS`` variable
+   for more information. The default priority, if unspecified for a
+   layer with no dependencies, is the lowest defined priority + 1 (or 1
+   if no priorities are defined).
+   .. tip::
+      You can use the command
+      bitbake-layers show-layers
+      to list all configured layers along with their priorities.
+BBFILES
+   A space-separated list of recipe files BitBake uses to build
+   software.
+   When specifying recipe files, you can pattern match using Python's
+   ```glob`` <https://docs.python.org/3/library/glob.html>`__ syntax.
+   For details on the syntax, see the documentation by following the
+   previous link.
+BBFILES_DYNAMIC
+   Activates content when identified layers are present. You identify
+   the layers by the collections that the layers define.
+   Use the ``BBFILES_DYNAMIC`` variable to avoid ``.bbappend`` files
+   whose corresponding ``.bb`` file is in a layer that attempts to
+   modify other layers through ``.bbappend`` but does not want to
+   introduce a hard dependency on those other layers.
+   Use the following form for ``BBFILES_DYNAMIC``:
+   collection_name:filename_pattern The following example identifies two
+   collection names and two filename patterns: BBFILES_DYNAMIC += " \\
+   clang-layer:${LAYERDIR}/bbappends/meta-clang/*/*/*.bbappend \\
+   core:${LAYERDIR}/bbappends/openembedded-core/meta/*/*/*.bbappend \\ "
+   This next example shows an error message that occurs because invalid
+   entries are found, which cause parsing to abort: ERROR:
+   BBFILES_DYNAMIC entries must be of the form <collection
+   name>:<filename pattern>, not:
+   /work/my-layer/bbappends/meta-security-isafw/*/*/*.bbappend
+   /work/my-layer/bbappends/openembedded-core/meta/*/*/*.bbappend
+BBINCLUDELOGS
+   Variable that controls how BitBake displays logs on build failure.
+BBINCLUDELOGS_LINES
+   If ```BBINCLUDELOGS`` <#var-BBINCLUDELOGS>`__ is set, specifies the
+   maximum number of lines from the task log file to print when
+   reporting a failed task. If you do not set ``BBINCLUDELOGS_LINES``,
+   the entire log is printed.
+BBLAYERS
+   Lists the layers to enable during the build. This variable is defined
+   in the ``bblayers.conf`` configuration file in the `Build
+   Directory <#build-directory>`__. Here is an example: BBLAYERS = " \\
+   /home/scottrif/poky/meta \\ /home/scottrif/poky/meta-poky \\
+   /home/scottrif/poky/meta-yocto-bsp \\
+   /home/scottrif/poky/meta-mykernel \\ "
+   This example enables four layers, one of which is a custom,
+   user-defined layer named ``meta-mykernel``.
+BBMASK
+   Prevents BitBake from processing recipes and recipe append files.
+   You can use the ``BBMASK`` variable to "hide" these ``.bb`` and
+   ``.bbappend`` files. BitBake ignores any recipe or recipe append
+   files that match any of the expressions. It is as if BitBake does not
+   see them at all. Consequently, matching files are not parsed or
+   otherwise used by BitBake.
+   The values you provide are passed to Python's regular expression
+   compiler. Consequently, the syntax follows Python's Regular
+   Expression (re) syntax. The expressions are compared against the full
+   paths to the files. For complete syntax information, see Python's
+   documentation at ` <http://docs.python.org/3/library/re.html#re>`__.
+   The following example uses a complete regular expression to tell
+   BitBake to ignore all recipe and recipe append files in the
+   ``meta-ti/recipes-misc/`` directory: BBMASK = "meta-ti/recipes-misc/"
+   If you want to mask out multiple directories or recipes, you can
+   specify multiple regular expression fragments. This next example
+   masks out multiple directories and individual recipes: BBMASK +=
+   "/meta-ti/recipes-misc/ meta-ti/recipes-ti/packagegroup/" BBMASK +=
+   "/meta-oe/recipes-support/" BBMASK += "/meta-foo/.*/openldap" BBMASK
+   += "opencv.*\.bbappend" BBMASK += "lzma"
+   .. note::
+      When specifying a directory name, use the trailing slash character
+      to ensure you match just that directory name.
+BBMULTICONFIG
+   Specifies each additional separate configuration when you are
+   building targets with multiple configurations. Use this variable in
+   your ``conf/local.conf`` configuration file. Specify a
+   multiconfigname for each configuration file you are using. For
+   example, the following line specifies three configuration files:
+   BBMULTICONFIG = "configA configB configC" Each configuration file you
+   use must reside in the `Build Directory <#build-directory>`__
+   ``conf/multiconfig`` directory (e.g.
+   build_directory\ ``/conf/multiconfig/configA.conf``).
+   For information on how to use ``BBMULTICONFIG`` in an environment
+   that supports building targets with multiple configurations, see the
+   "`Building Images for Multiple Targets Using Multiple
+   Configurations <&YOCTO_DOCS_DEV_URL;#dev-building-images-for-multiple-targets-using-multiple-configurations>`__"
+   section in the Yocto Project Development Tasks Manual.
+BBPATH
+   Used by BitBake to locate ``.bbclass`` and configuration files. This
+   variable is analogous to the ``PATH`` variable.
+   .. note::
+      If you run BitBake from a directory outside of the
+      Build Directory
+      , you must be sure to set
+      BBPATH
+      to point to the Build Directory. Set the variable as you would any
+      environment variable and then run BitBake:
+      ::
+              $ BBPATH = "build_directory"
+              $ export BBPATH
+              $ bitbake target
+                                 
+BBSERVER
+   If defined in the BitBake environment, ``BBSERVER`` points to the
+   BitBake remote server.
+   Use the following format to export the variable to the BitBake
+   environment: export BBSERVER=localhost:$port
+   By default, ``BBSERVER`` also appears in
+   ```BB_HASHBASE_WHITELIST`` <&YOCTO_DOCS_BB_URL;#var-BB_HASHBASE_WHITELIST>`__.
+   Consequently, ``BBSERVER`` is excluded from checksum and dependency
+   data.
+BINCONFIG
+   When inheriting the
+   ```binconfig-disabled`` <#ref-classes-binconfig-disabled>`__ class,
+   this variable specifies binary configuration scripts to disable in
+   favor of using ``pkg-config`` to query the information. The
+   ``binconfig-disabled`` class will modify the specified scripts to
+   return an error so that calls to them can be easily found and
+   replaced.
+   To add multiple scripts, separate them by spaces. Here is an example
+   from the ``libpng`` recipe: BINCONFIG = "${bindir}/libpng-config
+   ${bindir}/libpng16-config"
+BINCONFIG_GLOB
+   When inheriting the ```binconfig`` <#ref-classes-binconfig>`__ class,
+   this variable specifies a wildcard for configuration scripts that
+   need editing. The scripts are edited to correct any paths that have
+   been set up during compilation so that they are correct for use when
+   installed into the sysroot and called by the build processes of other
+   recipes.
+   .. note::
+      The
+      BINCONFIG_GLOB
+      variable uses
+      shell globbing
+      , which is recognition and expansion of wildcards during pattern
+      matching. Shell globbing is very similar to
+      fnmatch
+      and
+      glob
+      .
+   For more information on how this variable works, see
+   ``meta/classes/binconfig.bbclass`` in the `Source
+   Directory <#source-directory>`__. You can also find general
+   information on the class in the
+   "```binconfig.bbclass`` <#ref-classes-binconfig>`__" section.
+BP
+   The base recipe name and version but without any special recipe name
+   suffix (i.e. ``-native``, ``lib64-``, and so forth). ``BP`` is
+   comprised of the following: ${BPN}-${PV}
+BPN
+   This variable is a version of the ```PN`` <#var-PN>`__ variable with
+   common prefixes and suffixes removed, such as ``nativesdk-``,
+   ``-cross``, ``-native``, and multilib's ``lib64-`` and ``lib32-``.
+   The exact lists of prefixes and suffixes removed are specified by the
+   ```MLPREFIX`` <#var-MLPREFIX>`__ and
+   ```SPECIAL_PKGSUFFIX`` <#var-SPECIAL_PKGSUFFIX>`__ variables,
+   respectively.
+BUGTRACKER
+   Specifies a URL for an upstream bug tracking website for a recipe.
+   The OpenEmbedded build system does not use this variable. Rather, the
+   variable is a useful pointer in case a bug in the software being
+   built needs to be manually reported.
+BUILD_ARCH
+   Specifies the architecture of the build host (e.g. ``i686``). The
+   OpenEmbedded build system sets the value of ``BUILD_ARCH`` from the
+   machine name reported by the ``uname`` command.
+BUILD_AS_ARCH
+   Specifies the architecture-specific assembler flags for the build
+   host. By default, the value of ``BUILD_AS_ARCH`` is empty.
+BUILD_CC_ARCH
+   Specifies the architecture-specific C compiler flags for the build
+   host. By default, the value of ``BUILD_CC_ARCH`` is empty.
+BUILD_CCLD
+   Specifies the linker command to be used for the build host when the C
+   compiler is being used as the linker. By default, ``BUILD_CCLD``
+   points to GCC and passes as arguments the value of
+   ```BUILD_CC_ARCH`` <#var-BUILD_CC_ARCH>`__, assuming
+   ``BUILD_CC_ARCH`` is set.
+BUILD_CFLAGS
+   Specifies the flags to pass to the C compiler when building for the
+   build host. When building in the ``-native`` context,
+   ```CFLAGS`` <#var-CFLAGS>`__ is set to the value of this variable by
+   default.
+BUILD_CPPFLAGS
+   Specifies the flags to pass to the C preprocessor (i.e. to both the C
+   and the C++ compilers) when building for the build host. When
+   building in the ``-native`` context, ```CPPFLAGS`` <#var-CPPFLAGS>`__
+   is set to the value of this variable by default.
+BUILD_CXXFLAGS
+   Specifies the flags to pass to the C++ compiler when building for the
+   build host. When building in the ``-native`` context,
+   ```CXXFLAGS`` <#var-CXXFLAGS>`__ is set to the value of this variable
+   by default.
+BUILD_FC
+   Specifies the Fortran compiler command for the build host. By
+   default, ``BUILD_FC`` points to Gfortran and passes as arguments the
+   value of ```BUILD_CC_ARCH`` <#var-BUILD_CC_ARCH>`__, assuming
+   ``BUILD_CC_ARCH`` is set.
+BUILD_LD
+   Specifies the linker command for the build host. By default,
+   ``BUILD_LD`` points to the GNU linker (ld) and passes as arguments
+   the value of ```BUILD_LD_ARCH`` <#var-BUILD_LD_ARCH>`__, assuming
+   ``BUILD_LD_ARCH`` is set.
+BUILD_LD_ARCH
+   Specifies architecture-specific linker flags for the build host. By
+   default, the value of ``BUILD_LD_ARCH`` is empty.
+BUILD_LDFLAGS
+   Specifies the flags to pass to the linker when building for the build
+   host. When building in the ``-native`` context,
+   ```LDFLAGS`` <#var-LDFLAGS>`__ is set to the value of this variable
+   by default.
+BUILD_OPTIMIZATION
+   Specifies the optimization flags passed to the C compiler when
+   building for the build host or the SDK. The flags are passed through
+   the ```BUILD_CFLAGS`` <#var-BUILD_CFLAGS>`__ and
+   ```BUILDSDK_CFLAGS`` <#var-BUILDSDK_CFLAGS>`__ default values.
+   The default value of the ``BUILD_OPTIMIZATION`` variable is "-O2
+   -pipe".
+BUILD_OS
+   Specifies the operating system in use on the build host (e.g.
+   "linux"). The OpenEmbedded build system sets the value of
+   ``BUILD_OS`` from the OS reported by the ``uname`` command - the
+   first word, converted to lower-case characters.
+BUILD_PREFIX
+   The toolchain binary prefix used for native recipes. The OpenEmbedded
+   build system uses the ``BUILD_PREFIX`` value to set the
+   ```TARGET_PREFIX`` <#var-TARGET_PREFIX>`__ when building for
+   ``native`` recipes.
+BUILD_STRIP
+   Specifies the command to be used to strip debugging symbols from
+   binaries produced for the build host. By default, ``BUILD_STRIP``
+   points to
+   ``${``\ ```BUILD_PREFIX`` <#var-BUILD_PREFIX>`__\ ``}strip``.
+BUILD_SYS
+   Specifies the system, including the architecture and the operating
+   system, to use when building for the build host (i.e. when building
+   ``native`` recipes).
+   The OpenEmbedded build system automatically sets this variable based
+   on ```BUILD_ARCH`` <#var-BUILD_ARCH>`__,
+   ```BUILD_VENDOR`` <#var-BUILD_VENDOR>`__, and
+   ```BUILD_OS`` <#var-BUILD_OS>`__. You do not need to set the
+   ``BUILD_SYS`` variable yourself.
+BUILD_VENDOR
+   Specifies the vendor name to use when building for the build host.
+   The default value is an empty string ("").
+BUILDDIR
+   Points to the location of the `Build Directory <#build-directory>`__.
+   You can define this directory indirectly through the
+   ````` <#structure-core-script>`__ script by passing in a Build
+   Directory path when you run the script. If you run the script and do
+   not provide a Build Directory path, the ``BUILDDIR`` defaults to
+   ``build`` in the current directory.
+BUILDHISTORY_COMMIT
+   When inheriting the ```buildhistory`` <#ref-classes-buildhistory>`__
+   class, this variable specifies whether or not to commit the build
+   history output in a local Git repository. If set to "1", this local
+   repository will be maintained automatically by the ``buildhistory``
+   class and a commit will be created on every build for changes to each
+   top-level subdirectory of the build history output (images, packages,
+   and sdk). If you want to track changes to build history over time,
+   you should set this value to "1".
+   By default, the ``buildhistory`` class does not commit the build
+   history output in a local Git repository: BUILDHISTORY_COMMIT ?= "0"
+BUILDHISTORY_COMMIT_AUTHOR
+   When inheriting the ```buildhistory`` <#ref-classes-buildhistory>`__
+   class, this variable specifies the author to use for each Git commit.
+   In order for the ``BUILDHISTORY_COMMIT_AUTHOR`` variable to work, the
+   ```BUILDHISTORY_COMMIT`` <#var-BUILDHISTORY_COMMIT>`__ variable must
+   be set to "1".
+   Git requires that the value you provide for the
+   ``BUILDHISTORY_COMMIT_AUTHOR`` variable takes the form of "name
+   email@host". Providing an email address or host that is not valid
+   does not produce an error.
+   By default, the ``buildhistory`` class sets the variable as follows:
+   BUILDHISTORY_COMMIT_AUTHOR ?= "buildhistory <buildhistory@${DISTRO}>"
+BUILDHISTORY_DIR
+   When inheriting the ```buildhistory`` <#ref-classes-buildhistory>`__
+   class, this variable specifies the directory in which build history
+   information is kept. For more information on how the variable works,
+   see the ``buildhistory.class``.
+   By default, the ``buildhistory`` class sets the directory as follows:
+   BUILDHISTORY_DIR ?= "${TOPDIR}/buildhistory"
+BUILDHISTORY_FEATURES
+   When inheriting the ```buildhistory`` <#ref-classes-buildhistory>`__
+   class, this variable specifies the build history features to be
+   enabled. For more information on how build history works, see the
+   "`Maintaining Build Output
+   Quality <&YOCTO_DOCS_DEV_URL;#maintaining-build-output-quality>`__"
+   section in the Yocto Project Development Tasks Manual.
+   You can specify these features in the form of a space-separated list:
+   -  *image:* Analysis of the contents of images, which includes the
+      list of installed packages among other things.
+   -  *package:* Analysis of the contents of individual packages.
+   -  *sdk:* Analysis of the contents of the software development kit
+      (SDK).
+   -  *task:* Save output file signatures for `shared
+      state <&YOCTO_DOCS_OM_URL;#shared-state-cache>`__ (sstate) tasks.
+      This saves one file per task and lists the SHA-256 checksums for
+      each file staged (i.e. the output of the task).
+   By default, the ``buildhistory`` class enables the following
+   features: BUILDHISTORY_FEATURES ?= "image package sdk"
+BUILDHISTORY_IMAGE_FILES
+   When inheriting the ```buildhistory`` <#ref-classes-buildhistory>`__
+   class, this variable specifies a list of paths to files copied from
+   the image contents into the build history directory under an
+   "image-files" directory in the directory for the image, so that you
+   can track the contents of each file. The default is to copy
+   ``/etc/passwd`` and ``/etc/group``, which allows you to monitor for
+   changes in user and group entries. You can modify the list to include
+   any file. Specifying an invalid path does not produce an error.
+   Consequently, you can include files that might not always be present.
+   By default, the ``buildhistory`` class provides paths to the
+   following files: BUILDHISTORY_IMAGE_FILES ?= "/etc/passwd /etc/group"
+BUILDHISTORY_PUSH_REPO
+   When inheriting the ```buildhistory`` <#ref-classes-buildhistory>`__
+   class, this variable optionally specifies a remote repository to
+   which build history pushes Git changes. In order for
+   ``BUILDHISTORY_PUSH_REPO`` to work,
+   ```BUILDHISTORY_COMMIT`` <#var-BUILDHISTORY_COMMIT>`__ must be set to
+   "1".
+   The repository should correspond to a remote address that specifies a
+   repository as understood by Git, or alternatively to a remote name
+   that you have set up manually using ``git remote`` within the local
+   repository.
+   By default, the ``buildhistory`` class sets the variable as follows:
+   BUILDHISTORY_PUSH_REPO ?= ""
+BUILDSDK_CFLAGS
+   Specifies the flags to pass to the C compiler when building for the
+   SDK. When building in the ``nativesdk-`` context,
+   ```CFLAGS`` <#var-CFLAGS>`__ is set to the value of this variable by
+   default.
+BUILDSDK_CPPFLAGS
+   Specifies the flags to pass to the C pre-processor (i.e. to both the
+   C and the C++ compilers) when building for the SDK. When building in
+   the ``nativesdk-`` context, ```CPPFLAGS`` <#var-CPPFLAGS>`__ is set
+   to the value of this variable by default.
+BUILDSDK_CXXFLAGS
+   Specifies the flags to pass to the C++ compiler when building for the
+   SDK. When building in the ``nativesdk-`` context,
+   ```CXXFLAGS`` <#var-CXXFLAGS>`__ is set to the value of this variable
+   by default.
+BUILDSDK_LDFLAGS
+   Specifies the flags to pass to the linker when building for the SDK.
+   When building in the ``nativesdk-`` context,
+   ```LDFLAGS`` <#var-LDFLAGS>`__ is set to the value of this variable
+   by default.
+BUILDSTATS_BASE
+   Points to the location of the directory that holds build statistics
+   when you use and enable the
+   ```buildstats`` <#ref-classes-buildstats>`__ class. The
+   ``BUILDSTATS_BASE`` directory defaults to
+   ``${``\ ```TMPDIR`` <#var-TMPDIR>`__\ ``}/buildstats/``.
+BUSYBOX_SPLIT_SUID
+   For the BusyBox recipe, specifies whether to split the output
+   executable file into two parts: one for features that require
+   ``setuid root``, and one for the remaining features (i.e. those that
+   do not require ``setuid root``).
+   The ``BUSYBOX_SPLIT_SUID`` variable defaults to "1", which results in
+   splitting the output executable file. Set the variable to "0" to get
+   a single output executable file.
+CACHE
+   Specifies the directory BitBake uses to store a cache of the
+   `Metadata <#metadata>`__ so it does not need to be parsed every time
+   BitBake is started.
+CC
+   The minimal command and arguments used to run the C compiler.
+CFLAGS
+   Specifies the flags to pass to the C compiler. This variable is
+   exported to an environment variable and thus made visible to the
+   software being built during the compilation step.
+   Default initialization for ``CFLAGS`` varies depending on what is
+   being built:
+   -  ```TARGET_CFLAGS`` <#var-TARGET_CFLAGS>`__ when building for the
+      target
+   -  ```BUILD_CFLAGS`` <#var-BUILD_CFLAGS>`__ when building for the
+      build host (i.e. ``-native``)
+   -  ```BUILDSDK_CFLAGS`` <#var-BUILDSDK_CFLAGS>`__ when building for
+      an SDK (i.e. ``nativesdk-``)
+CLASSOVERRIDE
+   An internal variable specifying the special class override that
+   should currently apply (e.g. "class-target", "class-native", and so
+   forth). The classes that use this variable (e.g.
+   ```native`` <#ref-classes-native>`__,
+   ```nativesdk`` <#ref-classes-nativesdk>`__, and so forth) set the
+   variable to appropriate values.
+   .. note::
+      CLASSOVERRIDE
+      gets its default "class-target" value from the
+      bitbake.conf
+      file.
+   As an example, the following override allows you to install extra
+   files, but only when building for the target:
+   do_install_append_class-target() { install my-extra-file
+   ${D}${sysconfdir} } Here is an example where ``FOO`` is set to
+   "native" when building for the build host, and to "other" when not
+   building for the build host: FOO_class-native = "native" FOO =
+   "other" The underlying mechanism behind ``CLASSOVERRIDE`` is simply
+   that it is included in the default value of
+   ```OVERRIDES`` <#var-OVERRIDES>`__.
+CLEANBROKEN
+   If set to "1" within a recipe, ``CLEANBROKEN`` specifies that the
+   ``make clean`` command does not work for the software being built.
+   Consequently, the OpenEmbedded build system will not try to run
+   ``make clean`` during the ```do_configure`` <#ref-tasks-configure>`__
+   task, which is the default behavior.
+COMBINED_FEATURES
+   Provides a list of hardware features that are enabled in both
+   ```MACHINE_FEATURES`` <#var-MACHINE_FEATURES>`__ and
+   ```DISTRO_FEATURES`` <#var-DISTRO_FEATURES>`__. This select list of
+   features contains features that make sense to be controlled both at
+   the machine and distribution configuration level. For example, the
+   "bluetooth" feature requires hardware support but should also be
+   optional at the distribution level, in case the hardware supports
+   Bluetooth but you do not ever intend to use it.
+COMMON_LICENSE_DIR
+   Points to ``meta/files/common-licenses`` in the `Source
+   Directory <#source-directory>`__, which is where generic license
+   files reside.
+COMPATIBLE_HOST
+   A regular expression that resolves to one or more hosts (when the
+   recipe is native) or one or more targets (when the recipe is
+   non-native) with which a recipe is compatible. The regular expression
+   is matched against ```HOST_SYS`` <#var-HOST_SYS>`__. You can use the
+   variable to stop recipes from being built for classes of systems with
+   which the recipes are not compatible. Stopping these builds is
+   particularly useful with kernels. The variable also helps to increase
+   parsing speed since the build system skips parsing recipes not
+   compatible with the current system.
+COMPATIBLE_MACHINE
+   A regular expression that resolves to one or more target machines
+   with which a recipe is compatible. The regular expression is matched
+   against ```MACHINEOVERRIDES`` <#var-MACHINEOVERRIDES>`__. You can use
+   the variable to stop recipes from being built for machines with which
+   the recipes are not compatible. Stopping these builds is particularly
+   useful with kernels. The variable also helps to increase parsing
+   speed since the build system skips parsing recipes not compatible
+   with the current machine.
+COMPLEMENTARY_GLOB
+   Defines wildcards to match when installing a list of complementary
+   packages for all the packages explicitly (or implicitly) installed in
+   an image.
+   .. note::
+      The
+      COMPLEMENTARY_GLOB
+      variable uses Unix filename pattern matching (
+      fnmatch
+      ), which is similar to the Unix style pathname pattern expansion (
+      glob
+      ).
+   The resulting list of complementary packages is associated with an
+   item that can be added to
+   ```IMAGE_FEATURES`` <#var-IMAGE_FEATURES>`__. An example usage of
+   this is the "dev-pkgs" item that when added to ``IMAGE_FEATURES``
+   will install -dev packages (containing headers and other development
+   files) for every package in the image.
+   To add a new feature item pointing to a wildcard, use a variable flag
+   to specify the feature item name and use the value to specify the
+   wildcard. Here is an example: COMPLEMENTARY_GLOB[dev-pkgs] = '*-dev'
+COMPONENTS_DIR
+   Stores sysroot components for each recipe. The OpenEmbedded build
+   system uses ``COMPONENTS_DIR`` when constructing recipe-specific
+   sysroots for other recipes.
+   The default is
+   "``${``\ ```STAGING_DIR`` <#var-STAGING_DIR>`__\ ``}-components``."
+   (i.e.
+   "``${``\ ```TMPDIR`` <#var-TMPDIR>`__\ ``}/sysroots-components``").
+CONF_VERSION
+   Tracks the version of the local configuration file (i.e.
+   ``local.conf``). The value for ``CONF_VERSION`` increments each time
+   ``build/conf/`` compatibility changes.
+CONFFILES
+   Identifies editable or configurable files that are part of a package.
+   If the Package Management System (PMS) is being used to update
+   packages on the target system, it is possible that configuration
+   files you have changed after the original installation and that you
+   now want to remain unchanged are overwritten. In other words,
+   editable files might exist in the package that you do not want reset
+   as part of the package update process. You can use the ``CONFFILES``
+   variable to list the files in the package that you wish to prevent
+   the PMS from overwriting during this update process.
+   To use the ``CONFFILES`` variable, provide a package name override
+   that identifies the resulting package. Then, provide a
+   space-separated list of files. Here is an example: CONFFILES_${PN} +=
+   "${sysconfdir}/file1 \\ ${sysconfdir}/file2 ${sysconfdir}/file3"
+   A relationship exists between the ``CONFFILES`` and ``FILES``
+   variables. The files listed within ``CONFFILES`` must be a subset of
+   the files listed within ``FILES``. Because the configuration files
+   you provide with ``CONFFILES`` are simply being identified so that
+   the PMS will not overwrite them, it makes sense that the files must
+   already be included as part of the package through the ``FILES``
+   variable.
+   .. note::
+      When specifying paths as part of the
+      CONFFILES
+      variable, it is good practice to use appropriate path variables.
+      For example,
+      ${sysconfdir}
+      rather than
+      /etc
+      or
+      ${bindir}
+      rather than
+      /usr/bin
+      . You can find a list of these variables at the top of the
+      meta/conf/bitbake.conf
+      file in the
+      Source Directory
+      .
+CONFIG_INITRAMFS_SOURCE
+   Identifies the initial RAM filesystem (initramfs) source files. The
+   OpenEmbedded build system receives and uses this kernel Kconfig
+   variable as an environment variable. By default, the variable is set
+   to null ("").
+   The ``CONFIG_INITRAMFS_SOURCE`` can be either a single cpio archive
+   with a ``.cpio`` suffix or a space-separated list of directories and
+   files for building the initramfs image. A cpio archive should contain
+   a filesystem archive to be used as an initramfs image. Directories
+   should contain a filesystem layout to be included in the initramfs
+   image. Files should contain entries according to the format described
+   by the ``usr/gen_init_cpio`` program in the kernel tree.
+   If you specify multiple directories and files, the initramfs image
+   will be the aggregate of all of them.
+   For information on creating an initramfs, see the "`Building an
+   Initial RAM Filesystem (initramfs)
+   Image <&YOCTO_DOCS_DEV_URL;#building-an-initramfs-image>`__" section
+   in the Yocto Project Development Tasks Manual.
+CONFIG_SITE
+   A list of files that contains ``autoconf`` test results relevant to
+   the current build. This variable is used by the Autotools utilities
+   when running ``configure``.
+CONFIGURE_FLAGS
+   The minimal arguments for GNU configure.
+CONFLICT_DISTRO_FEATURES
+   When inheriting the
+   ```distro_features_check`` <#ref-classes-distro_features_check>`__
+   class, this variable identifies distribution features that would be
+   in conflict should the recipe be built. In other words, if the
+   ``CONFLICT_DISTRO_FEATURES`` variable lists a feature that also
+   appears in ``DISTRO_FEATURES`` within the current configuration, an
+   error occurs and the build stops.
+COPYLEFT_LICENSE_EXCLUDE
+   A space-separated list of licenses to exclude from the source
+   archived by the ```archiver`` <#ref-classes-archiver>`__ class. In
+   other words, if a license in a recipe's
+   ```LICENSE`` <#var-LICENSE>`__ value is in the value of
+   ``COPYLEFT_LICENSE_EXCLUDE``, then its source is not archived by the
+   class.
+   .. note::
+      The
+      COPYLEFT_LICENSE_EXCLUDE
+      variable takes precedence over the
+      COPYLEFT_LICENSE_INCLUDE
+      variable.
+   The default value, which is "CLOSED Proprietary", for
+   ``COPYLEFT_LICENSE_EXCLUDE`` is set by the
+   ```copyleft_filter`` <#ref-classes-copyleft_filter>`__ class, which
+   is inherited by the ``archiver`` class.
+COPYLEFT_LICENSE_INCLUDE
+   A space-separated list of licenses to include in the source archived
+   by the ```archiver`` <#ref-classes-archiver>`__ class. In other
+   words, if a license in a recipe's ```LICENSE`` <#var-LICENSE>`__
+   value is in the value of ``COPYLEFT_LICENSE_INCLUDE``, then its
+   source is archived by the class.
+   The default value is set by the
+   ```copyleft_filter`` <#ref-classes-copyleft_filter>`__ class, which
+   is inherited by the ``archiver`` class. The default value includes
+   "GPL*", "LGPL*", and "AGPL*".
+COPYLEFT_PN_EXCLUDE
+   A list of recipes to exclude in the source archived by the
+   ```archiver`` <#ref-classes-archiver>`__ class. The
+   ``COPYLEFT_PN_EXCLUDE`` variable overrides the license inclusion and
+   exclusion caused through the
+   ```COPYLEFT_LICENSE_INCLUDE`` <#var-COPYLEFT_LICENSE_INCLUDE>`__ and
+   ```COPYLEFT_LICENSE_EXCLUDE`` <#var-COPYLEFT_LICENSE_EXCLUDE>`__
+   variables, respectively.
+   The default value, which is "" indicating to not explicitly exclude
+   any recipes by name, for ``COPYLEFT_PN_EXCLUDE`` is set by the
+   ```copyleft_filter`` <#ref-classes-copyleft_filter>`__ class, which
+   is inherited by the ``archiver`` class.
+COPYLEFT_PN_INCLUDE
+   A list of recipes to include in the source archived by the
+   ```archiver`` <#ref-classes-archiver>`__ class. The
+   ``COPYLEFT_PN_INCLUDE`` variable overrides the license inclusion and
+   exclusion caused through the
+   ```COPYLEFT_LICENSE_INCLUDE`` <#var-COPYLEFT_LICENSE_INCLUDE>`__ and
+   ```COPYLEFT_LICENSE_EXCLUDE`` <#var-COPYLEFT_LICENSE_EXCLUDE>`__
+   variables, respectively.
+   The default value, which is "" indicating to not explicitly include
+   any recipes by name, for ``COPYLEFT_PN_INCLUDE`` is set by the
+   ```copyleft_filter`` <#ref-classes-copyleft_filter>`__ class, which
+   is inherited by the ``archiver`` class.
+COPYLEFT_RECIPE_TYPES
+   A space-separated list of recipe types to include in the source
+   archived by the ```archiver`` <#ref-classes-archiver>`__ class.
+   Recipe types are ``target``, ``native``, ``nativesdk``, ``cross``,
+   ``crosssdk``, and ``cross-canadian``.
+   The default value, which is "target*", for ``COPYLEFT_RECIPE_TYPES``
+   is set by the ```copyleft_filter`` <#ref-classes-copyleft_filter>`__
+   class, which is inherited by the ``archiver`` class.
+COPY_LIC_DIRS
+   If set to "1" along with the
+   ```COPY_LIC_MANIFEST`` <#var-COPY_LIC_MANIFEST>`__ variable, the
+   OpenEmbedded build system copies into the image the license files,
+   which are located in ``/usr/share/common-licenses``, for each
+   package. The license files are placed in directories within the image
+   itself during build time.
+   .. note::
+      The
+      COPY_LIC_DIRS
+      does not offer a path for adding licenses for newly installed
+      packages to an image, which might be most suitable for read-only
+      filesystems that cannot be upgraded. See the
+      LICENSE_CREATE_PACKAGE
+      variable for additional information. You can also reference the "
+      Providing License Text
+      " section in the Yocto Project Development Tasks Manual for
+      information on providing license text.
+COPY_LIC_MANIFEST
+   If set to "1", the OpenEmbedded build system copies the license
+   manifest for the image to
+   ``/usr/share/common-licenses/license.manifest`` within the image
+   itself during build time.
+   .. note::
+      The
+      COPY_LIC_MANIFEST
+      does not offer a path for adding licenses for newly installed
+      packages to an image, which might be most suitable for read-only
+      filesystems that cannot be upgraded. See the
+      LICENSE_CREATE_PACKAGE
+      variable for additional information. You can also reference the "
+      Providing License Text
+      " section in the Yocto Project Development Tasks Manual for
+      information on providing license text.
+CORE_IMAGE_EXTRA_INSTALL
+   Specifies the list of packages to be added to the image. You should
+   only set this variable in the ``local.conf`` configuration file found
+   in the `Build Directory <#build-directory>`__.
+   This variable replaces ``POKY_EXTRA_INSTALL``, which is no longer
+   supported.
+COREBASE
+   Specifies the parent directory of the OpenEmbedded-Core Metadata
+   layer (i.e. ``meta``).
+   It is an important distinction that ``COREBASE`` points to the parent
+   of this layer and not the layer itself. Consider an example where you
+   have cloned the Poky Git repository and retained the ``poky`` name
+   for your local copy of the repository. In this case, ``COREBASE``
+   points to the ``poky`` folder because it is the parent directory of
+   the ``poky/meta`` layer.
+COREBASE_FILES
+   Lists files from the ```COREBASE`` <#var-COREBASE>`__ directory that
+   should be copied other than the layers listed in the
+   ``bblayers.conf`` file. The ``COREBASE_FILES`` variable exists for
+   the purpose of copying metadata from the OpenEmbedded build system
+   into the extensible SDK.
+   Explicitly listing files in ``COREBASE`` is needed because it
+   typically contains build directories and other files that should not
+   normally be copied into the extensible SDK. Consequently, the value
+   of ``COREBASE_FILES`` is used in order to only copy the files that
+   are actually needed.
+CPP
+   The minimal command and arguments used to run the C preprocessor.
+CPPFLAGS
+   Specifies the flags to pass to the C pre-processor (i.e. to both the
+   C and the C++ compilers). This variable is exported to an environment
+   variable and thus made visible to the software being built during the
+   compilation step.
+   Default initialization for ``CPPFLAGS`` varies depending on what is
+   being built:
+   -  ```TARGET_CPPFLAGS`` <#var-TARGET_CPPFLAGS>`__ when building for
+      the target
+   -  ```BUILD_CPPFLAGS`` <#var-BUILD_CPPFLAGS>`__ when building for the
+      build host (i.e. ``-native``)
+   -  ```BUILDSDK_CPPFLAGS`` <#var-BUILDSDK_CPPFLAGS>`__ when building
+      for an SDK (i.e. ``nativesdk-``)
+CROSS_COMPILE
+   The toolchain binary prefix for the target tools. The
+   ``CROSS_COMPILE`` variable is the same as the
+   ```TARGET_PREFIX`` <#var-TARGET_PREFIX>`__ variable.
+   .. note::
+      The OpenEmbedded build system sets the
+      CROSS_COMPILE
+      variable only in certain contexts (e.g. when building for kernel
+      and kernel module recipes).
+CVSDIR
+   The directory in which files checked out under the CVS system are
+   stored.
+CXX
+   The minimal command and arguments used to run the C++ compiler.
+CXXFLAGS
+   Specifies the flags to pass to the C++ compiler. This variable is
+   exported to an environment variable and thus made visible to the
+   software being built during the compilation step.
+   Default initialization for ``CXXFLAGS`` varies depending on what is
+   being built:
+   -  ```TARGET_CXXFLAGS`` <#var-TARGET_CXXFLAGS>`__ when building for
+      the target
+   -  ```BUILD_CXXFLAGS`` <#var-BUILD_CXXFLAGS>`__ when building for the
+      build host (i.e. ``-native``)
+   -  ```BUILDSDK_CXXFLAGS`` <#var-BUILDSDK_CXXFLAGS>`__ when building
+      for an SDK (i.e. ``nativesdk-``)
+D
+   The destination directory. The location in the `Build
+   Directory <#build-directory>`__ where components are installed by the
+   ```do_install`` <#ref-tasks-install>`__ task. This location defaults
+   to: ${WORKDIR}/image
+   .. note::
+      Tasks that read from or write to this directory should run under
+      fakeroot
+      .
+DATE
+   The date the build was started. Dates appear using the year, month,
+   and day (YMD) format (e.g. "20150209" for February 9th, 2015).
+DATETIME
+   The date and time on which the current build started. The format is
+   suitable for timestamps.
+DEBIAN_NOAUTONAME
+   When the ```debian`` <#ref-classes-debian>`__ class is inherited,
+   which is the default behavior, ``DEBIAN_NOAUTONAME`` specifies a
+   particular package should not be renamed according to Debian library
+   package naming. You must use the package name as an override when you
+   set this variable. Here is an example from the ``fontconfig`` recipe:
+   DEBIAN_NOAUTONAME_fontconfig-utils = "1"
+DEBIANNAME
+   When the ```debian`` <#ref-classes-debian>`__ class is inherited,
+   which is the default behavior, ``DEBIANNAME`` allows you to override
+   the library name for an individual package. Overriding the library
+   name in these cases is rare. You must use the package name as an
+   override when you set this variable. Here is an example from the
+   ``dbus`` recipe: DEBIANNAME_${PN} = "dbus-1"
+DEBUG_BUILD
+   Specifies to build packages with debugging information. This
+   influences the value of the ``SELECTED_OPTIMIZATION`` variable.
+DEBUG_OPTIMIZATION
+   The options to pass in ``TARGET_CFLAGS`` and ``CFLAGS`` when
+   compiling a system for debugging. This variable defaults to "-O
+   -fno-omit-frame-pointer ${DEBUG_FLAGS} -pipe".
+DEFAULT_PREFERENCE
+   Specifies a weak bias for recipe selection priority.
+   The most common usage of this is variable is to set it to "-1" within
+   a recipe for a development version of a piece of software. Using the
+   variable in this way causes the stable version of the recipe to build
+   by default in the absence of ``PREFERRED_VERSION`` being used to
+   build the development version.
+   .. note::
+      The bias provided by
+      DEFAULT_PREFERENCE
+      is weak and is overridden by
+      BBFILE_PRIORITY
+      if that variable is different between two layers that contain
+      different versions of the same recipe.
+DEFAULTTUNE
+   The default CPU and Application Binary Interface (ABI) tunings (i.e.
+   the "tune") used by the OpenEmbedded build system. The
+   ``DEFAULTTUNE`` helps define
+   ```TUNE_FEATURES`` <#var-TUNE_FEATURES>`__.
+   The default tune is either implicitly or explicitly set by the
+   machine (```MACHINE`` <#var-MACHINE>`__). However, you can override
+   the setting using available tunes as defined with
+   ```AVAILTUNES`` <#var-AVAILTUNES>`__.
+DEPENDS
+   Lists a recipe's build-time dependencies. These are dependencies on
+   other recipes whose contents (e.g. headers and shared libraries) are
+   needed by the recipe at build time.
+   As an example, consider a recipe ``foo`` that contains the following
+   assignment: DEPENDS = "bar" The practical effect of the previous
+   assignment is that all files installed by bar will be available in
+   the appropriate staging sysroot, given by the
+   ```STAGING_DIR*`` <#var-STAGING_DIR>`__ variables, by the time the
+   ```do_configure`` <#ref-tasks-configure>`__ task for ``foo`` runs.
+   This mechanism is implemented by having ``do_configure`` depend on
+   the ```do_populate_sysroot`` <#ref-tasks-populate_sysroot>`__ task of
+   each recipe listed in ``DEPENDS``, through a
+   ``[``\ ```deptask`` <&YOCTO_DOCS_BB_URL;#variable-flags>`__\ ``]``
+   declaration in the ```base`` <#ref-classes-base>`__ class.
+   .. note::
+      It seldom is necessary to reference, for example,
+      STAGING_DIR_HOST
+      explicitly. The standard classes and build-related variables are
+      configured to automatically use the appropriate staging sysroots.
+   As another example, ``DEPENDS`` can also be used to add utilities
+   that run on the build machine during the build. For example, a recipe
+   that makes use of a code generator built by the recipe ``codegen``
+   might have the following: DEPENDS = "codegen-native" For more
+   information, see the ```native`` <#ref-classes-native>`__ class and
+   the ```EXTRANATIVEPATH`` <#var-EXTRANATIVEPATH>`__ variable.
+   .. note::
+      -  ``DEPENDS`` is a list of recipe names. Or, to be more precise,
+         it is a list of ```PROVIDES`` <#var-PROVIDES>`__ names, which
+         usually match recipe names. Putting a package name such as
+         "foo-dev" in ``DEPENDS`` does not make sense. Use "foo"
+         instead, as this will put files from all the packages that make
+         up ``foo``, which includes those from ``foo-dev``, into the
+         sysroot.
+      -  One recipe having another recipe in ``DEPENDS`` does not by
+         itself add any runtime dependencies between the packages
+         produced by the two recipes. However, as explained in the
+         "`Automatically Added Runtime
+         Dependencies <&YOCTO_DOCS_OM_URL;#automatically-added-runtime-dependencies>`__"
+         section in the Yocto Project Overview and Concepts Manual,
+         runtime dependencies will often be added automatically, meaning
+         ``DEPENDS`` alone is sufficient for most recipes.
+      -  Counterintuitively, ``DEPENDS`` is often necessary even for
+         recipes that install precompiled components. For example, if
+         ``libfoo`` is a precompiled library that links against
+         ``libbar``, then linking against ``libfoo`` requires both
+         ``libfoo`` and ``libbar`` to be available in the sysroot.
+         Without a ``DEPENDS`` from the recipe that installs ``libfoo``
+         to the recipe that installs ``libbar``, other recipes might
+         fail to link against ``libfoo``.
+   For information on runtime dependencies, see the
+   ```RDEPENDS`` <#var-RDEPENDS>`__ variable. You can also see the
+   "`Tasks <&YOCTO_DOCS_BB_URL;#tasks>`__" and
+   "`Dependencies <&YOCTO_DOCS_BB_URL;#dependencies>`__" sections in the
+   BitBake User Manual for additional information on tasks and
+   dependencies.
+DEPLOY_DIR
+   Points to the general area that the OpenEmbedded build system uses to
+   place images, packages, SDKs, and other output files that are ready
+   to be used outside of the build system. By default, this directory
+   resides within the `Build Directory <#build-directory>`__ as
+   ``${TMPDIR}/deploy``.
+   For more information on the structure of the Build Directory, see
+   "`The Build Directory - ``build/`` <#structure-build>`__" section.
+   For more detail on the contents of the ``deploy`` directory, see the
+   "`Images <&YOCTO_DOCS_OM_URL;#images-dev-environment>`__", "`Package
+   Feeds <&YOCTO_DOCS_OM_URL;#package-feeds-dev-environment>`__", and
+   "`Application Development
+   SDK <&YOCTO_DOCS_OM_URL;#sdk-dev-environment>`__" sections all in the
+   Yocto Project Overview and Concepts Manual.
+DEPLOY_DIR_DEB
+   Points to the area that the OpenEmbedded build system uses to place
+   Debian packages that are ready to be used outside of the build
+   system. This variable applies only when
+   ```PACKAGE_CLASSES`` <#var-PACKAGE_CLASSES>`__ contains
+   "package_deb".
+   The BitBake configuration file initially defines the
+   ``DEPLOY_DIR_DEB`` variable as a sub-folder of
+   ```DEPLOY_DIR`` <#var-DEPLOY_DIR>`__: DEPLOY_DIR_DEB =
+   "${DEPLOY_DIR}/deb"
+   The ```package_deb`` <#ref-classes-package_deb>`__ class uses the
+   ``DEPLOY_DIR_DEB`` variable to make sure the
+   ```do_package_write_deb`` <#ref-tasks-package_write_deb>`__ task
+   writes Debian packages into the appropriate folder. For more
+   information on how packaging works, see the "`Package
+   Feeds <&YOCTO_DOCS_OM_URL;#package-feeds-dev-environment>`__" section
+   in the Yocto Project Overview and Concepts Manual.
+DEPLOY_DIR_IMAGE
+   Points to the area that the OpenEmbedded build system uses to place
+   images and other associated output files that are ready to be
+   deployed onto the target machine. The directory is machine-specific
+   as it contains the ``${MACHINE}`` name. By default, this directory
+   resides within the `Build Directory <#build-directory>`__ as
+   ``${DEPLOY_DIR}/images/${MACHINE}/``.
+   For more information on the structure of the Build Directory, see
+   "`The Build Directory - ``build/`` <#structure-build>`__" section.
+   For more detail on the contents of the ``deploy`` directory, see the
+   "`Images <&YOCTO_DOCS_OM_URL;#images-dev-environment>`__" and
+   "`Application Development
+   SDK <&YOCTO_DOCS_OM_URL;#sdk-dev-environment>`__" sections both in
+   the Yocto Project Overview and Concepts Manual.
+DEPLOY_DIR_IPK
+   Points to the area that the OpenEmbedded build system uses to place
+   IPK packages that are ready to be used outside of the build system.
+   This variable applies only when
+   ```PACKAGE_CLASSES`` <#var-PACKAGE_CLASSES>`__ contains
+   "package_ipk".
+   The BitBake configuration file initially defines this variable as a
+   sub-folder of ```DEPLOY_DIR`` <#var-DEPLOY_DIR>`__: DEPLOY_DIR_IPK =
+   "${DEPLOY_DIR}/ipk"
+   The ```package_ipk`` <#ref-classes-package_ipk>`__ class uses the
+   ``DEPLOY_DIR_IPK`` variable to make sure the
+   ```do_package_write_ipk`` <#ref-tasks-package_write_ipk>`__ task
+   writes IPK packages into the appropriate folder. For more information
+   on how packaging works, see the "`Package
+   Feeds <&YOCTO_DOCS_OM_URL;#package-feeds-dev-environment>`__" section
+   in the Yocto Project Overview and Concepts Manual.
+DEPLOY_DIR_RPM
+   Points to the area that the OpenEmbedded build system uses to place
+   RPM packages that are ready to be used outside of the build system.
+   This variable applies only when
+   ```PACKAGE_CLASSES`` <#var-PACKAGE_CLASSES>`__ contains
+   "package_rpm".
+   The BitBake configuration file initially defines this variable as a
+   sub-folder of ```DEPLOY_DIR`` <#var-DEPLOY_DIR>`__: DEPLOY_DIR_RPM =
+   "${DEPLOY_DIR}/rpm"
+   The ```package_rpm`` <#ref-classes-package_rpm>`__ class uses the
+   ``DEPLOY_DIR_RPM`` variable to make sure the
+   ```do_package_write_rpm`` <#ref-tasks-package_write_rpm>`__ task
+   writes RPM packages into the appropriate folder. For more information
+   on how packaging works, see the "`Package
+   Feeds <&YOCTO_DOCS_OM_URL;#package-feeds-dev-environment>`__" section
+   in the Yocto Project Overview and Concepts Manual.
+DEPLOY_DIR_TAR
+   Points to the area that the OpenEmbedded build system uses to place
+   tarballs that are ready to be used outside of the build system. This
+   variable applies only when
+   ```PACKAGE_CLASSES`` <#var-PACKAGE_CLASSES>`__ contains
+   "package_tar".
+   The BitBake configuration file initially defines this variable as a
+   sub-folder of ```DEPLOY_DIR`` <#var-DEPLOY_DIR>`__: DEPLOY_DIR_TAR =
+   "${DEPLOY_DIR}/tar"
+   The ```package_tar`` <#ref-classes-package_tar>`__ class uses the
+   ``DEPLOY_DIR_TAR`` variable to make sure the
+   ```do_package_write_tar`` <#ref-tasks-package_write_tar>`__ task
+   writes TAR packages into the appropriate folder. For more information
+   on how packaging works, see the "`Package
+   Feeds <&YOCTO_DOCS_OM_URL;#package-feeds-dev-environment>`__" section
+   in the Yocto Project Overview and Concepts Manual.
+DEPLOYDIR
+   When inheriting the ```deploy`` <#ref-classes-deploy>`__ class, the
+   ``DEPLOYDIR`` points to a temporary work area for deployed files that
+   is set in the ``deploy`` class as follows: DEPLOYDIR =
+   "${WORKDIR}/deploy-${```PN`` <#var-PN>`__}"
+   Recipes inheriting the ``deploy`` class should copy files to be
+   deployed into ``DEPLOYDIR``, and the class will take care of copying
+   them into ```DEPLOY_DIR_IMAGE`` <#var-DEPLOY_DIR_IMAGE>`__
+   afterwards.
+DESCRIPTION
+   The package description used by package managers. If not set,
+   ``DESCRIPTION`` takes the value of the ```SUMMARY`` <#var-SUMMARY>`__
+   variable.
+DISTRO
+   The short name of the distribution. For information on the long name
+   of the distribution, see the ```DISTRO_NAME`` <#var-DISTRO_NAME>`__
+   variable.
+   The ``DISTRO`` variable corresponds to a distribution configuration
+   file whose root name is the same as the variable's argument and whose
+   filename extension is ``.conf``. For example, the distribution
+   configuration file for the Poky distribution is named ``poky.conf``
+   and resides in the ``meta-poky/conf/distro`` directory of the `Source
+   Directory <#source-directory>`__.
+   Within that ``poky.conf`` file, the ``DISTRO`` variable is set as
+   follows: DISTRO = "poky"
+   Distribution configuration files are located in a ``conf/distro``
+   directory within the `Metadata <#metadata>`__ that contains the
+   distribution configuration. The value for ``DISTRO`` must not contain
+   spaces, and is typically all lower-case.
+   .. note::
+      If the
+      DISTRO
+      variable is blank, a set of default configurations are used, which
+      are specified within
+      meta/conf/distro/defaultsetup.conf
+      also in the Source Directory.
+DISTRO_CODENAME
+   Specifies a codename for the distribution being built.
+DISTRO_EXTRA_RDEPENDS
+   Specifies a list of distro-specific packages to add to all images.
+   This variable takes affect through ``packagegroup-base`` so the
+   variable only really applies to the more full-featured images that
+   include ``packagegroup-base``. You can use this variable to keep
+   distro policy out of generic images. As with all other distro
+   variables, you set this variable in the distro ``.conf`` file.
+DISTRO_EXTRA_RRECOMMENDS
+   Specifies a list of distro-specific packages to add to all images if
+   the packages exist. The packages might not exist or be empty (e.g.
+   kernel modules). The list of packages are automatically installed but
+   you can remove them.
+DISTRO_FEATURES
+   The software support you want in your distribution for various
+   features. You define your distribution features in the distribution
+   configuration file.
+   In most cases, the presence or absence of a feature in
+   ``DISTRO_FEATURES`` is translated to the appropriate option supplied
+   to the configure script during the
+   ```do_configure`` <#ref-tasks-configure>`__ task for recipes that
+   optionally support the feature. For example, specifying "x11" in
+   ``DISTRO_FEATURES``, causes every piece of software built for the
+   target that can optionally support X11 to have its X11 support
+   enabled.
+   Two more examples are Bluetooth and NFS support. For a more complete
+   list of features that ships with the Yocto Project and that you can
+   provide with this variable, see the "`Distro
+   Features <#ref-features-distro>`__" section.
+DISTRO_FEATURES_BACKFILL
+   Features to be added to ``DISTRO_FEATURES`` if not also present in
+   ``DISTRO_FEATURES_BACKFILL_CONSIDERED``.
+   This variable is set in the ``meta/conf/bitbake.conf`` file. It is
+   not intended to be user-configurable. It is best to just reference
+   the variable to see which distro features are being backfilled for
+   all distro configurations. See the "`Feature
+   Backfilling <#ref-features-backfill>`__" section for more
+   information.
+DISTRO_FEATURES_BACKFILL_CONSIDERED
+   Features from ``DISTRO_FEATURES_BACKFILL`` that should not be
+   backfilled (i.e. added to ``DISTRO_FEATURES``) during the build. See
+   the "`Feature Backfilling <#ref-features-backfill>`__" section for
+   more information.
+DISTRO_FEATURES_DEFAULT
+   A convenience variable that gives you the default list of distro
+   features with the exception of any features specific to the C library
+   (``libc``).
+   When creating a custom distribution, you might find it useful to be
+   able to reuse the default
+   ```DISTRO_FEATURES`` <#var-DISTRO_FEATURES>`__ options without the
+   need to write out the full set. Here is an example that uses
+   ``DISTRO_FEATURES_DEFAULT`` from a custom distro configuration file:
+   DISTRO_FEATURES ?= "${DISTRO_FEATURES_DEFAULT} myfeature"
+DISTRO_FEATURES_FILTER_NATIVE
+   Specifies a list of features that if present in the target
+   ```DISTRO_FEATURES`` <#var-DISTRO_FEATURES>`__ value should be
+   included in ``DISTRO_FEATURES`` when building native recipes. This
+   variable is used in addition to the features filtered using the
+   ```DISTRO_FEATURES_NATIVE`` <#var-DISTRO_FEATURES_NATIVE>`__
+   variable.
+DISTRO_FEATURES_FILTER_NATIVESDK
+   Specifies a list of features that if present in the target
+   ```DISTRO_FEATURES`` <#var-DISTRO_FEATURES>`__ value should be
+   included in ``DISTRO_FEATURES`` when building nativesdk recipes. This
+   variable is used in addition to the features filtered using the
+   ```DISTRO_FEATURES_NATIVESDK`` <#var-DISTRO_FEATURES_NATIVESDK>`__
+   variable.
+DISTRO_FEATURES_NATIVE
+   Specifies a list of features that should be included in
+   ```DISTRO_FEATURES`` <#var-DISTRO_FEATURES>`__ when building native
+   recipes. This variable is used in addition to the features filtered
+   using the
+   ```DISTRO_FEATURES_FILTER_NATIVE`` <#var-DISTRO_FEATURES_FILTER_NATIVE>`__
+   variable.
+DISTRO_FEATURES_NATIVESDK
+   Specifies a list of features that should be included in
+   ```DISTRO_FEATURES`` <#var-DISTRO_FEATURES>`__ when building
+   nativesdk recipes. This variable is used in addition to the features
+   filtered using the
+   ```DISTRO_FEATURES_FILTER_NATIVESDK`` <#var-DISTRO_FEATURES_FILTER_NATIVESDK>`__
+   variable.
+DISTRO_NAME
+   The long name of the distribution. For information on the short name
+   of the distribution, see the ```DISTRO`` <#var-DISTRO>`__ variable.
+   The ``DISTRO_NAME`` variable corresponds to a distribution
+   configuration file whose root name is the same as the variable's
+   argument and whose filename extension is ``.conf``. For example, the
+   distribution configuration file for the Poky distribution is named
+   ``poky.conf`` and resides in the ``meta-poky/conf/distro`` directory
+   of the `Source Directory <#source-directory>`__.
+   Within that ``poky.conf`` file, the ``DISTRO_NAME`` variable is set
+   as follows: DISTRO_NAME = "Poky (Yocto Project Reference Distro)"
+   Distribution configuration files are located in a ``conf/distro``
+   directory within the `Metadata <#metadata>`__ that contains the
+   distribution configuration.
+   .. note::
+      If the
+      DISTRO_NAME
+      variable is blank, a set of default configurations are used, which
+      are specified within
+      meta/conf/distro/defaultsetup.conf
+      also in the Source Directory.
+DISTRO_VERSION
+   The version of the distribution.
+DISTROOVERRIDES
+   A colon-separated list of overrides specific to the current
+   distribution. By default, this list includes the value of
+   ```DISTRO`` <#var-DISTRO>`__.
+   You can extend ``DISTROOVERRIDES`` to add extra overrides that should
+   apply to the distribution.
+   The underlying mechanism behind ``DISTROOVERRIDES`` is simply that it
+   is included in the default value of
+   ```OVERRIDES`` <#var-OVERRIDES>`__.
+DL_DIR
+   The central download directory used by the build process to store
+   downloads. By default, ``DL_DIR`` gets files suitable for mirroring
+   for everything except Git repositories. If you want tarballs of Git
+   repositories, use the
+   ```BB_GENERATE_MIRROR_TARBALLS`` <#var-BB_GENERATE_MIRROR_TARBALLS>`__
+   variable.
+   You can set this directory by defining the ``DL_DIR`` variable in the
+   ``conf/local.conf`` file. This directory is self-maintaining and you
+   should not have to touch it. By default, the directory is
+   ``downloads`` in the `Build Directory <#build-directory>`__. #DL_DIR
+   ?= "${TOPDIR}/downloads" To specify a different download directory,
+   simply remove the comment from the line and provide your directory.
+   During a first build, the system downloads many different source code
+   tarballs from various upstream projects. Downloading can take a
+   while, particularly if your network connection is slow. Tarballs are
+   all stored in the directory defined by ``DL_DIR`` and the build
+   system looks there first to find source tarballs.
+   .. note::
+      When wiping and rebuilding, you can preserve this directory to
+      speed up this part of subsequent builds.
+   You can safely share this directory between multiple builds on the
+   same development machine. For additional information on how the build
+   process gets source files when working behind a firewall or proxy
+   server, see this specific question in the
+   "`FAQ <#how-does-the-yocto-project-obtain-source-code-and-will-it-work-behind-my-firewall-or-proxy-server>`__"
+   chapter. You can also refer to the "`Working Behind a Network
+   Proxy <&YOCTO_WIKI_URL;/wiki/Working_Behind_a_Network_Proxy>`__" Wiki
+   page.
+DOC_COMPRESS
+   When inheriting the ```compress_doc`` <#ref-classes-compress_doc>`__
+   class, this variable sets the compression policy used when the
+   OpenEmbedded build system compresses man pages and info pages. By
+   default, the compression method used is gz (gzip). Other policies
+   available are xz and bz2.
+   For information on policies and on how to use this variable, see the
+   comments in the ``meta/classes/compress_doc.bbclass`` file.
+EFI_PROVIDER
+   When building bootable images (i.e. where ``hddimg``, ``iso``, or
+   ``wic.vmdk`` is in ```IMAGE_FSTYPES`` <#var-IMAGE_FSTYPES>`__), the
+   ``EFI_PROVIDER`` variable specifies the EFI bootloader to use. The
+   default is "grub-efi", but "systemd-boot" can be used instead.
+   See the ```systemd-boot`` <#ref-classes-systemd-boot>`__ and
+   ```image-live`` <#ref-classes-image-live>`__ classes for more
+   information.
+ENABLE_BINARY_LOCALE_GENERATION
+   Variable that controls which locales for ``glibc`` are generated
+   during the build (useful if the target device has 64Mbytes of RAM or
+   less).
+ERR_REPORT_DIR
+   When used with the ```report-error`` <#ref-classes-report-error>`__
+   class, specifies the path used for storing the debug files created by
+   the `error reporting
+   tool <&YOCTO_DOCS_DEV_URL;#using-the-error-reporting-tool>`__, which
+   allows you to submit build errors you encounter to a central
+   database. By default, the value of this variable is
+   ``${``\ ```LOG_DIR`` <#var-LOG_DIR>`__\ ``}/error-report``.
+   You can set ``ERR_REPORT_DIR`` to the path you want the error
+   reporting tool to store the debug files as follows in your
+   ``local.conf`` file: ERR_REPORT_DIR = "path"
+ERROR_QA
+   Specifies the quality assurance checks whose failures are reported as
+   errors by the OpenEmbedded build system. You set this variable in
+   your distribution configuration file. For a list of the checks you
+   can control with this variable, see the
+   "```insane.bbclass`` <#ref-classes-insane>`__" section.
+EXCLUDE_FROM_SHLIBS
+   Triggers the OpenEmbedded build system's shared libraries resolver to
+   exclude an entire package when scanning for shared libraries.
+   .. note::
+      The shared libraries resolver's functionality results in part from
+      the internal function
+      package_do_shlibs
+      , which is part of the
+      do_package
+      task. You should be aware that the shared libraries resolver might
+      implicitly define some dependencies between packages.
+   The ``EXCLUDE_FROM_SHLIBS`` variable is similar to the
+   ```PRIVATE_LIBS`` <#var-PRIVATE_LIBS>`__ variable, which excludes a
+   package's particular libraries only and not the whole package.
+   Use the ``EXCLUDE_FROM_SHLIBS`` variable by setting it to "1" for a
+   particular package: EXCLUDE_FROM_SHLIBS = "1"
+EXCLUDE_FROM_WORLD
+   Directs BitBake to exclude a recipe from world builds (i.e.
+   ``bitbake world``). During world builds, BitBake locates, parses and
+   builds all recipes found in every layer exposed in the
+   ``bblayers.conf`` configuration file.
+   To exclude a recipe from a world build using this variable, set the
+   variable to "1" in the recipe.
+   .. note::
+      Recipes added to
+      EXCLUDE_FROM_WORLD
+      may still be built during a world build in order to satisfy
+      dependencies of other recipes. Adding a recipe to
+      EXCLUDE_FROM_WORLD
+      only ensures that the recipe is not explicitly added to the list
+      of build targets in a world build.
+EXTENDPE
+   Used with file and pathnames to create a prefix for a recipe's
+   version based on the recipe's ```PE`` <#var-PE>`__ value. If ``PE``
+   is set and greater than zero for a recipe, ``EXTENDPE`` becomes that
+   value (e.g if ``PE`` is equal to "1" then ``EXTENDPE`` becomes "1_").
+   If a recipe's ``PE`` is not set (the default) or is equal to zero,
+   ``EXTENDPE`` becomes "".
+   See the ```STAMP`` <#var-STAMP>`__ variable for an example.
+EXTENDPKGV
+   The full package version specification as it appears on the final
+   packages produced by a recipe. The variable's value is normally used
+   to fix a runtime dependency to the exact same version of another
+   package in the same recipe: RDEPENDS_${PN}-additional-module = "${PN}
+   (= ${EXTENDPKGV})"
+   The dependency relationships are intended to force the package
+   manager to upgrade these types of packages in lock-step.
+EXTERNAL_KERNEL_TOOLS
+   When set, the ``EXTERNAL_KERNEL_TOOLS`` variable indicates that these
+   tools are not in the source tree.
+   When kernel tools are available in the tree, they are preferred over
+   any externally installed tools. Setting the ``EXTERNAL_KERNEL_TOOLS``
+   variable tells the OpenEmbedded build system to prefer the installed
+   external tools. See the
+   ```kernel-yocto`` <#ref-classes-kernel-yocto>`__ class in
+   ``meta/classes`` to see how the variable is used.
+EXTERNALSRC
+   When inheriting the ```externalsrc`` <#ref-classes-externalsrc>`__
+   class, this variable points to the source tree, which is outside of
+   the OpenEmbedded build system. When set, this variable sets the
+   ```S`` <#var-S>`__ variable, which is what the OpenEmbedded build
+   system uses to locate unpacked recipe source code.
+   For more information on ``externalsrc.bbclass``, see the
+   "```externalsrc.bbclass`` <#ref-classes-externalsrc>`__" section. You
+   can also find information on how to use this variable in the
+   "`Building Software from an External
+   Source <&YOCTO_DOCS_DEV_URL;#building-software-from-an-external-source>`__"
+   section in the Yocto Project Development Tasks Manual.
+EXTERNALSRC_BUILD
+   When inheriting the ```externalsrc`` <#ref-classes-externalsrc>`__
+   class, this variable points to the directory in which the recipe's
+   source code is built, which is outside of the OpenEmbedded build
+   system. When set, this variable sets the ```B`` <#var-B>`__ variable,
+   which is what the OpenEmbedded build system uses to locate the Build
+   Directory.
+   For more information on ``externalsrc.bbclass``, see the
+   "```externalsrc.bbclass`` <#ref-classes-externalsrc>`__" section. You
+   can also find information on how to use this variable in the
+   "`Building Software from an External
+   Source <&YOCTO_DOCS_DEV_URL;#building-software-from-an-external-source>`__"
+   section in the Yocto Project Development Tasks Manual.
+EXTRA_AUTORECONF
+   For recipes inheriting the ```autotools`` <#ref-classes-autotools>`__
+   class, you can use ``EXTRA_AUTORECONF`` to specify extra options to
+   pass to the ``autoreconf`` command that is executed during the
+   ```do_configure`` <#ref-tasks-configure>`__ task.
+   The default value is "--exclude=autopoint".
+EXTRA_IMAGE_FEATURES
+   A list of additional features to include in an image. When listing
+   more than one feature, separate them with a space.
+   Typically, you configure this variable in your ``local.conf`` file,
+   which is found in the `Build Directory <#build-directory>`__.
+   Although you can use this variable from within a recipe, best
+   practices dictate that you do not.
+   .. note::
+      To enable primary features from within the image recipe, use the
+      IMAGE_FEATURES
+      variable.
+   Here are some examples of features you can add: "dbg-pkgs" - Adds
+   -dbg packages for all installed packages including symbol information
+   for debugging and profiling. "debug-tweaks" - Makes an image suitable
+   for debugging. For example, allows root logins without passwords and
+   enables post-installation logging. See the 'allow-empty-password' and
+   'post-install-logging' features in the "`Image
+   Features <#ref-features-image>`__" section for more information.
+   "dev-pkgs" - Adds -dev packages for all installed packages. This is
+   useful if you want to develop against the libraries in the image.
+   "read-only-rootfs" - Creates an image whose root filesystem is
+   read-only. See the "`Creating a Read-Only Root
+   Filesystem <&YOCTO_DOCS_DEV_URL;#creating-a-read-only-root-filesystem>`__"
+   section in the Yocto Project Development Tasks Manual for more
+   information "tools-debug" - Adds debugging tools such as gdb and
+   strace. "tools-sdk" - Adds development tools such as gcc, make,
+   pkgconfig and so forth. "tools-testapps" - Adds useful testing tools
+   such as ts_print, aplay, arecord and so forth.
+   For a complete list of image features that ships with the Yocto
+   Project, see the "`Image Features <#ref-features-image>`__" section.
+   For an example that shows how to customize your image by using this
+   variable, see the "`Customizing Images Using Custom
+   ``IMAGE_FEATURES`` and
+   ``EXTRA_IMAGE_FEATURES`` <&YOCTO_DOCS_DEV_URL;#usingpoky-extend-customimage-imagefeatures>`__"
+   section in the Yocto Project Development Tasks Manual.
+EXTRA_IMAGECMD
+   Specifies additional options for the image creation command that has
+   been specified in ```IMAGE_CMD`` <#var-IMAGE_CMD>`__. When setting
+   this variable, use an override for the associated image type. Here is
+   an example: EXTRA_IMAGECMD_ext3 ?= "-i 4096"
+EXTRA_IMAGEDEPENDS
+   A list of recipes to build that do not provide packages for
+   installing into the root filesystem.
+   Sometimes a recipe is required to build the final image but is not
+   needed in the root filesystem. You can use the ``EXTRA_IMAGEDEPENDS``
+   variable to list these recipes and thus specify the dependencies. A
+   typical example is a required bootloader in a machine configuration.
+   .. note::
+      To add packages to the root filesystem, see the various
+      \*
+      RDEPENDS
+      and
+      \*
+      RRECOMMENDS
+      variables.
+EXTRANATIVEPATH
+   A list of subdirectories of
+   ``${``\ ```STAGING_BINDIR_NATIVE`` <#var-STAGING_BINDIR_NATIVE>`__\ ``}``
+   added to the beginning of the environment variable ``PATH``. As an
+   example, the following prepends
+   "${STAGING_BINDIR_NATIVE}/foo:${STAGING_BINDIR_NATIVE}/bar:" to
+   ``PATH``: EXTRANATIVEPATH = "foo bar"
+EXTRA_OECMAKE
+   Additional `CMake <https://cmake.org/overview/>`__ options. See the
+   ```cmake`` <#ref-classes-cmake>`__ class for additional information.
+EXTRA_OECONF
+   Additional ``configure`` script options. See
+   ```PACKAGECONFIG_CONFARGS`` <#var-PACKAGECONFIG_CONFARGS>`__ for
+   additional information on passing configure script options.
+EXTRA_OEMAKE
+   Additional GNU ``make`` options.
+   Because the ``EXTRA_OEMAKE`` defaults to "", you need to set the
+   variable to specify any required GNU options.
+   ```PARALLEL_MAKE`` <#var-PARALLEL_MAKE>`__ and
+   ```PARALLEL_MAKEINST`` <#var-PARALLEL_MAKEINST>`__ also make use of
+   ``EXTRA_OEMAKE`` to pass the required flags.
+EXTRA_OESCONS
+   When inheriting the ```scons`` <#ref-classes-scons>`__ class, this
+   variable specifies additional configuration options you want to pass
+   to the ``scons`` command line.
+EXTRA_USERS_PARAMS
+   When inheriting the ```extrausers`` <#ref-classes-extrausers>`__
+   class, this variable provides image level user and group operations.
+   This is a more global method of providing user and group
+   configuration as compared to using the
+   ```useradd`` <#ref-classes-useradd>`__ class, which ties user and
+   group configurations to a specific recipe.
+   The set list of commands you can configure using the
+   ``EXTRA_USERS_PARAMS`` is shown in the ``extrausers`` class. These
+   commands map to the normal Unix commands of the same names: #
+   EXTRA_USERS_PARAMS = "\\ # useradd -p '' tester; \\ # groupadd
+   developers; \\ # userdel nobody; \\ # groupdel -g video; \\ #
+   groupmod -g 1020 developers; \\ # usermod -s /bin/sh tester; \\ # "
+FEATURE_PACKAGES
+   Defines one or more packages to include in an image when a specific
+   item is included in ```IMAGE_FEATURES`` <#var-IMAGE_FEATURES>`__.
+   When setting the value, ``FEATURE_PACKAGES`` should have the name of
+   the feature item as an override. Here is an example:
+   FEATURE_PACKAGES_widget = "package1 package2"
+   In this example, if "widget" were added to ``IMAGE_FEATURES``,
+   package1 and package2 would be included in the image.
+   .. note::
+      Packages installed by features defined through
+      FEATURE_PACKAGES
+      are often package groups. While similarly named, you should not
+      confuse the
+      FEATURE_PACKAGES
+      variable with package groups, which are discussed elsewhere in the
+      documentation.
+FEED_DEPLOYDIR_BASE_URI
+   Points to the base URL of the server and location within the
+   document-root that provides the metadata and packages required by
+   OPKG to support runtime package management of IPK packages. You set
+   this variable in your ``local.conf`` file.
+   Consider the following example: FEED_DEPLOYDIR_BASE_URI =
+   "http://192.168.7.1/BOARD-dir" This example assumes you are serving
+   your packages over HTTP and your databases are located in a directory
+   named ``BOARD-dir``, which is underneath your HTTP server's
+   document-root. In this case, the OpenEmbedded build system generates
+   a set of configuration files for you in your target that work with
+   the feed.
+FILES
+   The list of files and directories that are placed in a package. The
+   ```PACKAGES`` <#var-PACKAGES>`__ variable lists the packages
+   generated by a recipe.
+   To use the ``FILES`` variable, provide a package name override that
+   identifies the resulting package. Then, provide a space-separated
+   list of files or paths that identify the files you want included as
+   part of the resulting package. Here is an example: FILES_${PN} +=
+   "${bindir}/mydir1 ${bindir}/mydir2/myfile"
+   .. note::
+      -  When specifying files or paths, you can pattern match using
+         Python's
+         ```glob`` <https://docs.python.org/2/library/glob.html>`__
+         syntax. For details on the syntax, see the documentation by
+         following the previous link.
+      -  When specifying paths as part of the ``FILES`` variable, it is
+         good practice to use appropriate path variables. For example,
+         use ``${sysconfdir}`` rather than ``/etc``, or ``${bindir}``
+         rather than ``/usr/bin``. You can find a list of these
+         variables at the top of the ``meta/conf/bitbake.conf`` file in
+         the `Source Directory <#source-directory>`__. You will also
+         find the default values of the various ``FILES_*`` variables in
+         this file.
+   If some of the files you provide with the ``FILES`` variable are
+   editable and you know they should not be overwritten during the
+   package update process by the Package Management System (PMS), you
+   can identify these files so that the PMS will not overwrite them. See
+   the ```CONFFILES`` <#var-CONFFILES>`__ variable for information on
+   how to identify these files to the PMS.
+FILES_SOLIBSDEV
+   Defines the file specification to match
+   ```SOLIBSDEV`` <#var-SOLIBSDEV>`__. In other words,
+   ``FILES_SOLIBSDEV`` defines the full path name of the development
+   symbolic link (symlink) for shared libraries on the target platform.
+   The following statement from the ``bitbake.conf`` shows how it is
+   set: FILES_SOLIBSDEV ?= "${base_libdir}/lib*${SOLIBSDEV}
+   ${libdir}/lib*${SOLIBSDEV}"
+FILESEXTRAPATHS
+   Extends the search path the OpenEmbedded build system uses when
+   looking for files and patches as it processes recipes and append
+   files. The default directories BitBake uses when it processes recipes
+   are initially defined by the ```FILESPATH`` <#var-FILESPATH>`__
+   variable. You can extend ``FILESPATH`` variable by using
+   ``FILESEXTRAPATHS``.
+   Best practices dictate that you accomplish this by using
+   ``FILESEXTRAPATHS`` from within a ``.bbappend`` file and that you
+   prepend paths as follows: FILESEXTRAPATHS_prepend :=
+   "${THISDIR}/${PN}:" In the above example, the build system first
+   looks for files in a directory that has the same name as the
+   corresponding append file.
+   .. note::
+      When extending ``FILESEXTRAPATHS``, be sure to use the immediate
+      expansion (``:=``) operator. Immediate expansion makes sure that
+      BitBake evaluates ```THISDIR`` <#var-THISDIR>`__ at the time the
+      directive is encountered rather than at some later time when
+      expansion might result in a directory that does not contain the
+      files you need.
+      Also, include the trailing separating colon character if you are
+      prepending. The trailing colon character is necessary because you
+      are directing BitBake to extend the path by prepending directories
+      to the search path.
+   Here is another common use: FILESEXTRAPATHS_prepend :=
+   "${THISDIR}/files:" In this example, the build system extends the
+   ``FILESPATH`` variable to include a directory named ``files`` that is
+   in the same directory as the corresponding append file.
+   This next example specifically adds three paths:
+   FILESEXTRAPATHS_prepend := "path_1:path_2:path_3:"
+   A final example shows how you can extend the search path and include
+   a ```MACHINE`` <#var-MACHINE>`__-specific override, which is useful
+   in a BSP layer: FILESEXTRAPATHS_prepend_intel-x86-common :=
+   "${THISDIR}/${PN}:" The previous statement appears in the
+   ``linux-yocto-dev.bbappend`` file, which is found in the Yocto
+   Project `Source
+   Repositories <&YOCTO_DOCS_OM_URL;#source-repositories>`__ in
+   ``meta-intel/common/recipes-kernel/linux``. Here, the machine
+   override is a special ```PACKAGE_ARCH`` <#var-PACKAGE_ARCH>`__
+   definition for multiple ``meta-intel`` machines.
+   .. note::
+      For a layer that supports a single BSP, the override could just be
+      the value of
+      MACHINE
+      .
+   By prepending paths in ``.bbappend`` files, you allow multiple append
+   files that reside in different layers but are used for the same
+   recipe to correctly extend the path.
+FILESOVERRIDES
+   A subset of ```OVERRIDES`` <#var-OVERRIDES>`__ used by the
+   OpenEmbedded build system for creating
+   ```FILESPATH`` <#var-FILESPATH>`__. The ``FILESOVERRIDES`` variable
+   uses overrides to automatically extend the
+   ```FILESPATH`` <#var-FILESPATH>`__ variable. For an example of how
+   that works, see the ```FILESPATH`` <#var-FILESPATH>`__ variable
+   description. Additionally, you find more information on how overrides
+   are handled in the "`Conditional Syntax
+   (Overrides) <&YOCTO_DOCS_BB_URL;#conditional-syntax-overrides>`__"
+   section of the BitBake User Manual.
+   By default, the ``FILESOVERRIDES`` variable is defined as:
+   FILESOVERRIDES =
+   "${TRANSLATED_TARGET_ARCH}:${MACHINEOVERRIDES}:${DISTROOVERRIDES}"
+   .. note::
+      Do not hand-edit the
+      FILESOVERRIDES
+      variable. The values match up with expected overrides and are used
+      in an expected manner by the build system.
+FILESPATH
+   The default set of directories the OpenEmbedded build system uses
+   when searching for patches and files.
+   During the build process, BitBake searches each directory in
+   ``FILESPATH`` in the specified order when looking for files and
+   patches specified by each ``file://`` URI in a recipe's
+   ```SRC_URI`` <#var-SRC_URI>`__ statements.
+   The default value for the ``FILESPATH`` variable is defined in the
+   ``base.bbclass`` class found in ``meta/classes`` in the `Source
+   Directory <#source-directory>`__: FILESPATH =
+   "${@base_set_filespath(["${FILE_DIRNAME}/${BP}", \\
+   "${FILE_DIRNAME}/${BPN}", "${FILE_DIRNAME}/files"], d)}" The
+   ``FILESPATH`` variable is automatically extended using the overrides
+   from the ```FILESOVERRIDES`` <#var-FILESOVERRIDES>`__ variable.
+   .. note::
+      -  Do not hand-edit the ``FILESPATH`` variable. If you want the
+         build system to look in directories other than the defaults,
+         extend the ``FILESPATH`` variable by using the
+         ```FILESEXTRAPATHS`` <#var-FILESEXTRAPATHS>`__ variable.
+      -  Be aware that the default ``FILESPATH`` directories do not map
+         to directories in custom layers where append files
+         (``.bbappend``) are used. If you want the build system to find
+         patches or files that reside with your append files, you need
+         to extend the ``FILESPATH`` variable by using the
+         ``FILESEXTRAPATHS`` variable.
+   You can take advantage of this searching behavior in useful ways. For
+   example, consider a case where the following directory structure
+   exists for general and machine-specific configurations:
+   files/defconfig files/MACHINEA/defconfig files/MACHINEB/defconfig
+   Also in the example, the ``SRC_URI`` statement contains
+   "file://defconfig". Given this scenario, you can set
+   ```MACHINE`` <#var-MACHINE>`__ to "MACHINEA" and cause the build
+   system to use files from ``files/MACHINEA``. Set ``MACHINE`` to
+   "MACHINEB" and the build system uses files from ``files/MACHINEB``.
+   Finally, for any machine other than "MACHINEA" and "MACHINEB", the
+   build system uses files from ``files/defconfig``.
+   You can find out more about the patching process in the
+   "`Patching <&YOCTO_DOCS_OM_URL;#patching-dev-environment>`__" section
+   in the Yocto Project Overview and Concepts Manual and the "`Patching
+   Code <&YOCTO_DOCS_DEV_URL;#new-recipe-patching-code>`__" section in
+   the Yocto Project Development Tasks Manual. See the
+   ```do_patch`` <#ref-tasks-patch>`__ task as well.
+FILESYSTEM_PERMS_TABLES
+   Allows you to define your own file permissions settings table as part
+   of your configuration for the packaging process. For example, suppose
+   you need a consistent set of custom permissions for a set of groups
+   and users across an entire work project. It is best to do this in the
+   packages themselves but this is not always possible.
+   By default, the OpenEmbedded build system uses the ``fs-perms.txt``,
+   which is located in the ``meta/files`` folder in the `Source
+   Directory <#source-directory>`__. If you create your own file
+   permissions setting table, you should place it in your layer or the
+   distro's layer.
+   You define the ``FILESYSTEM_PERMS_TABLES`` variable in the
+   ``conf/local.conf`` file, which is found in the `Build
+   Directory <#build-directory>`__, to point to your custom
+   ``fs-perms.txt``. You can specify more than a single file permissions
+   setting table. The paths you specify to these files must be defined
+   within the ```BBPATH`` <#var-BBPATH>`__ variable.
+   For guidance on how to create your own file permissions settings
+   table file, examine the existing ``fs-perms.txt``.
+FIT_HASH_ALG
+   Specifies the hash algorithm used in creating the FIT Image. For e.g. sha256.
+FIT_SIGN_ALG</glossterm>
+   Specifies the signature algorithm used in creating the FIT Image.
+   For e.g. rsa2048.
+FONT_EXTRA_RDEPENDS
+   When inheriting the ```fontcache`` <#ref-classes-fontcache>`__ class,
+   this variable specifies the runtime dependencies for font packages.
+   By default, the ``FONT_EXTRA_RDEPENDS`` is set to "fontconfig-utils".
+FONT_PACKAGES
+   When inheriting the ```fontcache`` <#ref-classes-fontcache>`__ class,
+   this variable identifies packages containing font files that need to
+   be cached by Fontconfig. By default, the ``fontcache`` class assumes
+   that fonts are in the recipe's main package (i.e.
+   ``${``\ ```PN`` <#var-PN>`__\ ``}``). Use this variable if fonts you
+   need are in a package other than that main package.
+FORCE_RO_REMOVE
+   Forces the removal of the packages listed in ``ROOTFS_RO_UNNEEDED``
+   during the generation of the root filesystem.
+   Set the variable to "1" to force the removal of these packages.
+FULL_OPTIMIZATION
+   The options to pass in ``TARGET_CFLAGS`` and ``CFLAGS`` when
+   compiling an optimized system. This variable defaults to "-O2 -pipe
+   ${DEBUG_FLAGS}".
+GCCPIE
+   Enables Position Independent Executables (PIE) within the GNU C
+   Compiler (GCC). Enabling PIE in the GCC makes Return Oriented
+   Programming (ROP) attacks much more difficult to execute.
+   By default the ``security_flags.inc`` file enables PIE by setting the
+   variable as follows: GCCPIE ?= "--enable-default-pie"
+GCCVERSION
+   Specifies the default version of the GNU C Compiler (GCC) used for
+   compilation. By default, ``GCCVERSION`` is set to "8.x" in the
+   ``meta/conf/distro/include/tcmode-default.inc`` include file:
+   GCCVERSION ?= "8.%" You can override this value by setting it in a
+   configuration file such as the ``local.conf``.
+GDB
+   The minimal command and arguments to run the GNU Debugger.
+GITDIR
+   The directory in which a local copy of a Git repository is stored
+   when it is cloned.
+GLIBC_GENERATE_LOCALES
+   Specifies the list of GLIBC locales to generate should you not wish
+   to generate all LIBC locals, which can be time consuming.
+   .. note::
+      If you specifically remove the locale
+      en_US.UTF-8
+      , you must set
+      IMAGE_LINGUAS
+      appropriately.
+   You can set ``GLIBC_GENERATE_LOCALES`` in your ``local.conf`` file.
+   By default, all locales are generated. GLIBC_GENERATE_LOCALES =
+   "en_GB.UTF-8 en_US.UTF-8"
+GROUPADD_PARAM
+   When inheriting the ```useradd`` <#ref-classes-useradd>`__ class,
+   this variable specifies for a package what parameters should be
+   passed to the ``groupadd`` command if you wish to add a group to the
+   system when the package is installed.
+   Here is an example from the ``dbus`` recipe: GROUPADD_PARAM_${PN} =
+   "-r netdev" For information on the standard Linux shell command
+   ``groupadd``, see ` <http://linux.die.net/man/8/groupadd>`__.
+GROUPMEMS_PARAM
+   When inheriting the ```useradd`` <#ref-classes-useradd>`__ class,
+   this variable specifies for a package what parameters should be
+   passed to the ``groupmems`` command if you wish to modify the members
+   of a group when the package is installed.
+   For information on the standard Linux shell command ``groupmems``,
+   see ` <http://linux.die.net/man/8/groupmems>`__.
+GRUB_GFXSERIAL
+   Configures the GNU GRand Unified Bootloader (GRUB) to have graphics
+   and serial in the boot menu. Set this variable to "1" in your
+   ``local.conf`` or distribution configuration file to enable graphics
+   and serial in the menu.
+   See the ```grub-efi`` <#ref-classes-grub-efi>`__ class for more
+   information on how this variable is used.
+GRUB_OPTS
+   Additional options to add to the GNU GRand Unified Bootloader (GRUB)
+   configuration. Use a semi-colon character (``;``) to separate
+   multiple options.
+   The ``GRUB_OPTS`` variable is optional. See the
+   ```grub-efi`` <#ref-classes-grub-efi>`__ class for more information
+   on how this variable is used.
+GRUB_TIMEOUT
+   Specifies the timeout before executing the default ``LABEL`` in the
+   GNU GRand Unified Bootloader (GRUB).
+   The ``GRUB_TIMEOUT`` variable is optional. See the
+   ```grub-efi`` <#ref-classes-grub-efi>`__ class for more information
+   on how this variable is used.
+GTKIMMODULES_PACKAGES
+   When inheriting the
+   ```gtk-immodules-cache`` <#ref-classes-gtk-immodules-cache>`__ class,
+   this variable specifies the packages that contain the GTK+ input
+   method modules being installed when the modules are in packages other
+   than the main package.
+HOMEPAGE
+   Website where more information about the software the recipe is
+   building can be found.
+HOST_ARCH
+   The name of the target architecture, which is normally the same as
+   ```TARGET_ARCH`` <#var-TARGET_ARCH>`__. The OpenEmbedded build system
+   supports many architectures. Here is an example list of architectures
+   supported. This list is by no means complete as the architecture is
+   configurable: arm i586 x86_64 powerpc powerpc64 mips mipsel
+HOST_CC_ARCH
+   Specifies architecture-specific compiler flags that are passed to the
+   C compiler.
+   Default initialization for ``HOST_CC_ARCH`` varies depending on what
+   is being built:
+   -  ```TARGET_CC_ARCH`` <#var-TARGET_CC_ARCH>`__ when building for the
+      target
+   -  ``BUILD_CC_ARCH`` when building for the build host (i.e.
+      ``-native``)
+   -  ``BUILDSDK_CC_ARCH`` when building for an SDK (i.e.
+      ``nativesdk-``)
+HOST_OS
+   Specifies the name of the target operating system, which is normally
+   the same as the ```TARGET_OS`` <#var-TARGET_OS>`__. The variable can
+   be set to "linux" for ``glibc``-based systems and to "linux-musl" for
+   ``musl``. For ARM/EABI targets, there are also "linux-gnueabi" and
+   "linux-musleabi" values possible.
+HOST_PREFIX
+   Specifies the prefix for the cross-compile toolchain. ``HOST_PREFIX``
+   is normally the same as ```TARGET_PREFIX`` <#var-TARGET_PREFIX>`__.
+HOST_SYS
+   Specifies the system, including the architecture and the operating
+   system, for which the build is occurring in the context of the
+   current recipe.
+   The OpenEmbedded build system automatically sets this variable based
+   on ```HOST_ARCH`` <#var-HOST_ARCH>`__,
+   ```HOST_VENDOR`` <#var-HOST_VENDOR>`__, and
+   ```HOST_OS`` <#var-HOST_OS>`__ variables.
+   .. note::
+      You do not need to set the variable yourself.
+   Consider these two examples:
+   -  Given a native recipe on a 32-bit x86 machine running Linux, the
+      value is "i686-linux".
+   -  Given a recipe being built for a little-endian MIPS target running
+      Linux, the value might be "mipsel-linux".
+HOSTTOOLS
+   A space-separated list (filter) of tools on the build host that
+   should be allowed to be called from within build tasks. Using this
+   filter helps reduce the possibility of host contamination. If a tool
+   specified in the value of ``HOSTTOOLS`` is not found on the build
+   host, the OpenEmbedded build system produces an error and the build
+   is not started.
+   For additional information, see
+   ```HOSTTOOLS_NONFATAL`` <#var-HOSTTOOLS_NONFATAL>`__.
+HOSTTOOLS_NONFATAL
+   A space-separated list (filter) of tools on the build host that
+   should be allowed to be called from within build tasks. Using this
+   filter helps reduce the possibility of host contamination. Unlike
+   ```HOSTTOOLS`` <#var-HOSTTOOLS>`__, the OpenEmbedded build system
+   does not produce an error if a tool specified in the value of
+   ``HOSTTOOLS_NONFATAL`` is not found on the build host. Thus, you can
+   use ``HOSTTOOLS_NONFATAL`` to filter optional host tools.
+HOST_VENDOR
+   Specifies the name of the vendor. ``HOST_VENDOR`` is normally the
+   same as ```TARGET_VENDOR`` <#var-TARGET_VENDOR>`__.
+ICECC_DISABLED
+   Disables or enables the ``icecc`` (Icecream) function. For more
+   information on this function and best practices for using this
+   variable, see the "```icecc.bbclass`` <#ref-classes-icecc>`__"
+   section.
+   Setting this variable to "1" in your ``local.conf`` disables the
+   function: ICECC_DISABLED ??= "1" To enable the function, set the
+   variable as follows: ICECC_DISABLED = ""
+ICECC_ENV_EXEC
+   Points to the ``icecc-create-env`` script that you provide. This
+   variable is used by the ```icecc`` <#ref-classes-icecc>`__ class. You
+   set this variable in your ``local.conf`` file.
+   If you do not point to a script that you provide, the OpenEmbedded
+   build system uses the default script provided by the
+   ``icecc-create-env.bb`` recipe, which is a modified version and not
+   the one that comes with ``icecc``.
+ICECC_PARALLEL_MAKE
+   Extra options passed to the ``make`` command during the
+   ```do_compile`` <#ref-tasks-compile>`__ task that specify parallel
+   compilation. This variable usually takes the form of "-j x", where x
+   represents the maximum number of parallel threads ``make`` can run.
+   .. note::
+      The options passed affect builds on all enabled machines on the
+      network, which are machines running the
+      iceccd
+      daemon.
+   If your enabled machines support multiple cores, coming up with the
+   maximum number of parallel threads that gives you the best
+   performance could take some experimentation since machine speed,
+   network lag, available memory, and existing machine loads can all
+   affect build time. Consequently, unlike the
+   ```PARALLEL_MAKE`` <#var-PARALLEL_MAKE>`__ variable, there is no
+   rule-of-thumb for setting ``ICECC_PARALLEL_MAKE`` to achieve optimal
+   performance.
+   If you do not set ``ICECC_PARALLEL_MAKE``, the build system does not
+   use it (i.e. the system does not detect and assign the number of
+   cores as is done with ``PARALLEL_MAKE``).
+ICECC_PATH
+   The location of the ``icecc`` binary. You can set this variable in
+   your ``local.conf`` file. If your ``local.conf`` file does not define
+   this variable, the ```icecc`` <#ref-classes-icecc>`__ class attempts
+   to define it by locating ``icecc`` using ``which``.
+ICECC_USER_CLASS_BL
+   Identifies user classes that you do not want the Icecream distributed
+   compile support to consider. This variable is used by the
+   ```icecc`` <#ref-classes-icecc>`__ class. You set this variable in
+   your ``local.conf`` file.
+   When you list classes using this variable, you are "blacklisting"
+   them from distributed compilation across remote hosts. Any classes
+   you list will be distributed and compiled locally.
+ICECC_USER_PACKAGE_BL
+   Identifies user recipes that you do not want the Icecream distributed
+   compile support to consider. This variable is used by the
+   ```icecc`` <#ref-classes-icecc>`__ class. You set this variable in
+   your ``local.conf`` file.
+   When you list packages using this variable, you are "blacklisting"
+   them from distributed compilation across remote hosts. Any packages
+   you list will be distributed and compiled locally.
+ICECC_USER_PACKAGE_WL
+   Identifies user recipes that use an empty
+   ```PARALLEL_MAKE`` <#var-PARALLEL_MAKE>`__ variable that you want to
+   force remote distributed compilation on using the Icecream
+   distributed compile support. This variable is used by the
+   ```icecc`` <#ref-classes-icecc>`__ class. You set this variable in
+   your ``local.conf`` file.
+IMAGE_BASENAME
+   The base name of image output files. This variable defaults to the
+   recipe name (``${``\ ```PN`` <#var-PN>`__\ ``}``).
+IMAGE_BOOT_FILES
+   A space-separated list of files installed into the boot partition
+   when preparing an image using the Wic tool with the
+   ``bootimg-partition``  or ``bootimg-efi`` source plugin. By default,
+   the files are
+   installed under the same name as the source files. To change the
+   installed name, separate it from the original name with a semi-colon
+   (;). Source files need to be located in
+   ```DEPLOY_DIR_IMAGE`` <#var-DEPLOY_DIR_IMAGE>`__. Here are two
+   examples: IMAGE_BOOT_FILES = "u-boot.img uImage;kernel"
+   IMAGE_BOOT_FILES = "u-boot.${UBOOT_SUFFIX} ${KERNEL_IMAGETYPE}"
+   Alternatively, source files can be picked up using a glob pattern. In
+   this case, the destination file must have the same name as the base
+   name of the source file path. To install files into a directory
+   within the target location, pass its name after a semi-colon (;).
+   Here are two examples: IMAGE_BOOT_FILES = "bcm2835-bootfiles/*"
+   IMAGE_BOOT_FILES = "bcm2835-bootfiles/*;boot/" The first example
+   installs all files from ``${DEPLOY_DIR_IMAGE}/bcm2835-bootfiles``
+   into the root of the target partition. The second example installs
+   the same files into a ``boot`` directory within the target partition.
+   You can find information on how to use the Wic tool in the "`Creating
+   Partitioned Images Using
+   Wic <&YOCTO_DOCS_DEV_URL;#creating-partitioned-images-using-wic>`__"
+   section of the Yocto Project Development Tasks Manual. Reference
+   material for Wic is located in the "`OpenEmbedded Kickstart (.wks)
+   Reference <&YOCTO_DOCS_REF_URL;#ref-kickstart>`__" chapter.
+IMAGE_CLASSES
+   A list of classes that all images should inherit. You typically use
+   this variable to specify the list of classes that register the
+   different types of images the OpenEmbedded build system creates.
+   The default value for ``IMAGE_CLASSES`` is ``image_types``. You can
+   set this variable in your ``local.conf`` or in a distribution
+   configuration file.
+   For more information, see ``meta/classes/image_types.bbclass`` in the
+   `Source Directory <#source-directory>`__.
+IMAGE_CMD
+   Specifies the command to create the image file for a specific image
+   type, which corresponds to the value set set in
+   ```IMAGE_FSTYPES`` <#var-IMAGE_FSTYPES>`__, (e.g. ``ext3``,
+   ``btrfs``, and so forth). When setting this variable, you should use
+   an override for the associated type. Here is an example:
+   IMAGE_CMD_jffs2 = "mkfs.jffs2 --root=${IMAGE_ROOTFS} \\ --faketime
+   --output=${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.jffs2 \\
+   ${EXTRA_IMAGECMD}"
+   You typically do not need to set this variable unless you are adding
+   support for a new image type. For more examples on how to set this
+   variable, see the ```image_types`` <#ref-classes-image_types>`__
+   class file, which is ``meta/classes/image_types.bbclass``.
+IMAGE_DEVICE_TABLES
+   Specifies one or more files that contain custom device tables that
+   are passed to the ``makedevs`` command as part of creating an image.
+   These files list basic device nodes that should be created under
+   ``/dev`` within the image. If ``IMAGE_DEVICE_TABLES`` is not set,
+   ``files/device_table-minimal.txt`` is used, which is located by
+   ```BBPATH`` <#var-BBPATH>`__. For details on how you should write
+   device table files, see ``meta/files/device_table-minimal.txt`` as an
+   example.
+IMAGE_FEATURES
+   The primary list of features to include in an image. Typically, you
+   configure this variable in an image recipe. Although you can use this
+   variable from your ``local.conf`` file, which is found in the `Build
+   Directory <#build-directory>`__, best practices dictate that you do
+   not.
+   .. note::
+      To enable extra features from outside the image recipe, use the
+      EXTRA_IMAGE_FEATURES
+      variable.
+   For a list of image features that ships with the Yocto Project, see
+   the "`Image Features <#ref-features-image>`__" section.
+   For an example that shows how to customize your image by using this
+   variable, see the "`Customizing Images Using Custom
+   ``IMAGE_FEATURES`` and
+   ``EXTRA_IMAGE_FEATURES`` <&YOCTO_DOCS_DEV_URL;#usingpoky-extend-customimage-imagefeatures>`__"
+   section in the Yocto Project Development Tasks Manual.
+IMAGE_FSTYPES
+   Specifies the formats the OpenEmbedded build system uses during the
+   build when creating the root filesystem. For example, setting
+   ``IMAGE_FSTYPES`` as follows causes the build system to create root
+   filesystems using two formats: ``.ext3`` and ``.tar.bz2``:
+   IMAGE_FSTYPES = "ext3 tar.bz2"
+   For the complete list of supported image formats from which you can
+   choose, see ```IMAGE_TYPES`` <#var-IMAGE_TYPES>`__.
+   .. note::
+      -  If an image recipe uses the "inherit image" line and you are
+         setting ``IMAGE_FSTYPES`` inside the recipe, you must set
+         ``IMAGE_FSTYPES`` prior to using the "inherit image" line.
+      -  Due to the way the OpenEmbedded build system processes this
+         variable, you cannot update its contents by using ``_append``
+         or ``_prepend``. You must use the ``+=`` operator to add one or
+         more options to the ``IMAGE_FSTYPES`` variable.
+IMAGE_INSTALL
+   Used by recipes to specify the packages to install into an image
+   through the ```image`` <#ref-classes-image>`__ class. Use the
+   ``IMAGE_INSTALL`` variable with care to avoid ordering issues.
+   Image recipes set ``IMAGE_INSTALL`` to specify the packages to
+   install into an image through ``image.bbclass``. Additionally,
+   "helper" classes such as the
+   ```core-image`` <#ref-classes-core-image>`__ class exist that can
+   take lists used with ``IMAGE_FEATURES`` and turn them into
+   auto-generated entries in ``IMAGE_INSTALL`` in addition to its
+   default contents.
+   When you use this variable, it is best to use it as follows:
+   IMAGE_INSTALL_append = " package-name" Be sure to include the space
+   between the quotation character and the start of the package name or
+   names.
+   .. note::
+      -  When working with a
+         ```core-image-minimal-initramfs`` <#images-core-image-minimal-initramfs>`__
+         image, do not use the ``IMAGE_INSTALL`` variable to specify
+         packages for installation. Instead, use the
+         ```PACKAGE_INSTALL`` <#var-PACKAGE_INSTALL>`__ variable, which
+         allows the initial RAM filesystem (initramfs) recipe to use a
+         fixed set of packages and not be affected by ``IMAGE_INSTALL``.
+         For information on creating an initramfs, see the "`Building an
+         Initial RAM Filesystem (initramfs)
+         Image <&YOCTO_DOCS_DEV_URL;#building-an-initramfs-image>`__"
+         section in the Yocto Project Development Tasks Manual.
+      -  Using ``IMAGE_INSTALL`` with the
+         ```+=`` <&YOCTO_DOCS_BB_URL;#appending-and-prepending>`__
+         BitBake operator within the ``/conf/local.conf`` file or from
+         within an image recipe is not recommended. Use of this operator
+         in these ways can cause ordering issues. Since
+         ``core-image.bbclass`` sets ``IMAGE_INSTALL`` to a default
+         value using the
+         ```?=`` <&YOCTO_DOCS_BB_URL;#setting-a-default-value>`__
+         operator, using a ``+=`` operation against ``IMAGE_INSTALL``
+         results in unexpected behavior when used within
+         ``conf/local.conf``. Furthermore, the same operation from
+         within an image recipe may or may not succeed depending on the
+         specific situation. In both these cases, the behavior is
+         contrary to how most users expect the ``+=`` operator to work.
+IMAGE_LINGUAS
+   Specifies the list of locales to install into the image during the
+   root filesystem construction process. The OpenEmbedded build system
+   automatically splits locale files, which are used for localization,
+   into separate packages. Setting the ``IMAGE_LINGUAS`` variable
+   ensures that any locale packages that correspond to packages already
+   selected for installation into the image are also installed. Here is
+   an example: IMAGE_LINGUAS = "pt-br de-de"
+   In this example, the build system ensures any Brazilian Portuguese
+   and German locale files that correspond to packages in the image are
+   installed (i.e. ``*-locale-pt-br`` and ``*-locale-de-de`` as well as
+   ``*-locale-pt`` and ``*-locale-de``, since some software packages
+   only provide locale files by language and not by country-specific
+   language).
+   See the ```GLIBC_GENERATE_LOCALES`` <#var-GLIBC_GENERATE_LOCALES>`__
+   variable for information on generating GLIBC locales.
+IMAGE_MANIFEST
+   The manifest file for the image. This file lists all the installed
+   packages that make up the image. The file contains package
+   information on a line-per-package basis as follows: packagename
+   packagearch version
+   The ```image`` <#ref-classes-image>`__ class defines the manifest
+   file as follows: IMAGE_MANIFEST =
+   "${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.manifest" The location is
+   derived using the ```DEPLOY_DIR_IMAGE`` <#var-DEPLOY_DIR_IMAGE>`__
+   and ```IMAGE_NAME`` <#var-IMAGE_NAME>`__ variables. You can find
+   information on how the image is created in the "`Image
+   Generation <&YOCTO_DOCS_OM_URL;#image-generation-dev-environment>`__"
+   section in the Yocto Project Overview and Concepts Manual.
+IMAGE_NAME
+   The name of the output image files minus the extension. This variable
+   is derived using the ```IMAGE_BASENAME`` <#var-IMAGE_BASENAME>`__,
+   ```MACHINE`` <#var-MACHINE>`__, and ```DATETIME`` <#var-DATETIME>`__
+   variables: IMAGE_NAME = "${IMAGE_BASENAME}-${MACHINE}-${DATETIME}"
+IMAGE_OVERHEAD_FACTOR
+   Defines a multiplier that the build system applies to the initial
+   image size for cases when the multiplier times the returned disk
+   usage value for the image is greater than the sum of
+   ``IMAGE_ROOTFS_SIZE`` and ``IMAGE_ROOTFS_EXTRA_SPACE``. The result of
+   the multiplier applied to the initial image size creates free disk
+   space in the image as overhead. By default, the build process uses a
+   multiplier of 1.3 for this variable. This default value results in
+   30% free disk space added to the image when this method is used to
+   determine the final generated image size. You should be aware that
+   post install scripts and the package management system uses disk
+   space inside this overhead area. Consequently, the multiplier does
+   not produce an image with all the theoretical free disk space. See
+   ``IMAGE_ROOTFS_SIZE`` for information on how the build system
+   determines the overall image size.
+   The default 30% free disk space typically gives the image enough room
+   to boot and allows for basic post installs while still leaving a
+   small amount of free disk space. If 30% free space is inadequate, you
+   can increase the default value. For example, the following setting
+   gives you 50% free space added to the image: IMAGE_OVERHEAD_FACTOR =
+   "1.5"
+   Alternatively, you can ensure a specific amount of free disk space is
+   added to the image by using the ``IMAGE_ROOTFS_EXTRA_SPACE``
+   variable.
+IMAGE_PKGTYPE
+   Defines the package type (i.e. DEB, RPM, IPK, or TAR) used by the
+   OpenEmbedded build system. The variable is defined appropriately by
+   the ```package_deb`` <#ref-classes-package_deb>`__,
+   ```package_rpm`` <#ref-classes-package_rpm>`__,
+   ```package_ipk`` <#ref-classes-package_ipk>`__, or
+   ```package_tar`` <#ref-classes-package_tar>`__ class.
+   .. note::
+      The
+      package_tar
+      class is broken and is not supported. It is recommended that you
+      do not use it.
+   The ```populate_sdk_*`` <#ref-classes-populate-sdk-*>`__ and
+   ```image`` <#ref-classes-image>`__ classes use the ``IMAGE_PKGTYPE``
+   for packaging up images and SDKs.
+   You should not set the ``IMAGE_PKGTYPE`` manually. Rather, the
+   variable is set indirectly through the appropriate
+   ```package_*`` <#ref-classes-package>`__ class using the
+   ```PACKAGE_CLASSES`` <#var-PACKAGE_CLASSES>`__ variable. The
+   OpenEmbedded build system uses the first package type (e.g. DEB, RPM,
+   or IPK) that appears with the variable
+   .. note::
+      Files using the
+      .tar
+      format are never used as a substitute packaging format for DEB,
+      RPM, and IPK formatted files for your image or SDK.
+IMAGE_POSTPROCESS_COMMAND
+   Specifies a list of functions to call once the OpenEmbedded build
+   system creates the final image output files. You can specify
+   functions separated by semicolons: IMAGE_POSTPROCESS_COMMAND +=
+   "function; ... "
+   If you need to pass the root filesystem path to a command within the
+   function, you can use ``${IMAGE_ROOTFS}``, which points to the
+   directory that becomes the root filesystem image. See the
+   ```IMAGE_ROOTFS`` <#var-IMAGE_ROOTFS>`__ variable for more
+   information.
+IMAGE_PREPROCESS_COMMAND
+   Specifies a list of functions to call before the OpenEmbedded build
+   system creates the final image output files. You can specify
+   functions separated by semicolons: IMAGE_PREPROCESS_COMMAND +=
+   "function; ... "
+   If you need to pass the root filesystem path to a command within the
+   function, you can use ``${IMAGE_ROOTFS}``, which points to the
+   directory that becomes the root filesystem image. See the
+   ```IMAGE_ROOTFS`` <#var-IMAGE_ROOTFS>`__ variable for more
+   information.
+IMAGE_ROOTFS
+   The location of the root filesystem while it is under construction
+   (i.e. during the ```do_rootfs`` <#ref-tasks-rootfs>`__ task). This
+   variable is not configurable. Do not change it.
+IMAGE_ROOTFS_ALIGNMENT
+   Specifies the alignment for the output image file in Kbytes. If the
+   size of the image is not a multiple of this value, then the size is
+   rounded up to the nearest multiple of the value. The default value is
+   "1". See ```IMAGE_ROOTFS_SIZE`` <#var-IMAGE_ROOTFS_SIZE>`__ for
+   additional information.
+IMAGE_ROOTFS_EXTRA_SPACE
+   Defines additional free disk space created in the image in Kbytes. By
+   default, this variable is set to "0". This free disk space is added
+   to the image after the build system determines the image size as
+   described in ``IMAGE_ROOTFS_SIZE``.
+   This variable is particularly useful when you want to ensure that a
+   specific amount of free disk space is available on a device after an
+   image is installed and running. For example, to be sure 5 Gbytes of
+   free disk space is available, set the variable as follows:
+   IMAGE_ROOTFS_EXTRA_SPACE = "5242880"
+   For example, the Yocto Project Build Appliance specifically requests
+   40 Gbytes of extra space with the line: IMAGE_ROOTFS_EXTRA_SPACE =
+   "41943040"
+IMAGE_ROOTFS_SIZE
+   Defines the size in Kbytes for the generated image. The OpenEmbedded
+   build system determines the final size for the generated image using
+   an algorithm that takes into account the initial disk space used for
+   the generated image, a requested size for the image, and requested
+   additional free disk space to be added to the image. Programatically,
+   the build system determines the final size of the generated image as
+   follows: if (image-du \* overhead) < rootfs-size:
+   internal-rootfs-size = rootfs-size + xspace else:
+   internal-rootfs-size = (image-du \* overhead) + xspace where:
+   image-du = Returned value of the du command on the image. overhead =
+   IMAGE_OVERHEAD_FACTOR rootfs-size = IMAGE_ROOTFS_SIZE
+   internal-rootfs-size = Initial root filesystem size before any
+   modifications. xspace = IMAGE_ROOTFS_EXTRA_SPACE
+   See the ```IMAGE_OVERHEAD_FACTOR`` <#var-IMAGE_OVERHEAD_FACTOR>`__
+   and ```IMAGE_ROOTFS_EXTRA_SPACE`` <#var-IMAGE_ROOTFS_EXTRA_SPACE>`__
+   variables for related information.
+IMAGE_TYPEDEP
+   Specifies a dependency from one image type on another. Here is an
+   example from the ```image-live`` <#ref-classes-image-live>`__ class:
+   IMAGE_TYPEDEP_live = "ext3"
+   In the previous example, the variable ensures that when "live" is
+   listed with the ```IMAGE_FSTYPES`` <#var-IMAGE_FSTYPES>`__ variable,
+   the OpenEmbedded build system produces an ``ext3`` image first since
+   one of the components of the live image is an ``ext3`` formatted
+   partition containing the root filesystem.
+IMAGE_TYPES
+   Specifies the complete list of supported image types by default:
+   btrfs container cpio cpio.gz cpio.lz4 cpio.lzma cpio.xz cramfs ext2
+   ext2.bz2 ext2.gz ext2.lzma ext3 ext3.gz ext4 ext4.gz f2fs hddimg iso
+   jffs2 jffs2.sum multiubi squashfs squashfs-lz4 squashfs-lzo
+   squashfs-xz tar tar.bz2 tar.gz tar.lz4 tar.xz tar.zst ubi ubifs wic
+   wic.bz2 wic.gz wic.lzma
+   For more information about these types of images, see
+   ``meta/classes/image_types*.bbclass`` in the `Source
+   Directory <#source-directory>`__.
+INC_PR
+   Helps define the recipe revision for recipes that share a common
+   ``include`` file. You can think of this variable as part of the
+   recipe revision as set from within an include file.
+   Suppose, for example, you have a set of recipes that are used across
+   several projects. And, within each of those recipes the revision (its
+   ```PR`` <#var-PR>`__ value) is set accordingly. In this case, when
+   the revision of those recipes changes, the burden is on you to find
+   all those recipes and be sure that they get changed to reflect the
+   updated version of the recipe. In this scenario, it can get
+   complicated when recipes that are used in many places and provide
+   common functionality are upgraded to a new revision.
+   A more efficient way of dealing with this situation is to set the
+   ``INC_PR`` variable inside the ``include`` files that the recipes
+   share and then expand the ``INC_PR`` variable within the recipes to
+   help define the recipe revision.
+   The following provides an example that shows how to use the
+   ``INC_PR`` variable given a common ``include`` file that defines the
+   variable. Once the variable is defined in the ``include`` file, you
+   can use the variable to set the ``PR`` values in each recipe. You
+   will notice that when you set a recipe's ``PR`` you can provide more
+   granular revisioning by appending values to the ``INC_PR`` variable:
+   recipes-graphics/xorg-font/xorg-font-common.inc:INC_PR = "r2"
+   recipes-graphics/xorg-font/encodings_1.0.4.bb:PR = "${INC_PR}.1"
+   recipes-graphics/xorg-font/font-util_1.3.0.bb:PR = "${INC_PR}.0"
+   recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" The
+   first line of the example establishes the baseline revision to be
+   used for all recipes that use the ``include`` file. The remaining
+   lines in the example are from individual recipes and show how the
+   ``PR`` value is set.
+INCOMPATIBLE_LICENSE
+   Specifies a space-separated list of license names (as they would
+   appear in ```LICENSE`` <#var-LICENSE>`__) that should be excluded
+   from the build. Recipes that provide no alternatives to listed
+   incompatible licenses are not built. Packages that are individually
+   licensed with the specified incompatible licenses will be deleted.
+   .. note::
+      This functionality is only regularly tested using the following
+      setting:
+      ::
+              INCOMPATIBLE_LICENSE = "GPL-3.0 LGPL-3.0 AGPL-3.0"
+                             
+      Although you can use other settings, you might be required to
+      remove dependencies on or provide alternatives to components that
+      are required to produce a functional system image.
+   .. note::
+      It is possible to define a list of licenses that are allowed to be
+      used instead of the licenses that are excluded. To do this, define
+      a variable
+      COMPATIBLE_LICENSES
+      with the names of the licences that are allowed. Then define
+      INCOMPATIBLE_LICENSE
+      as:
+      ::
+              INCOMPATIBLE_LICENSE = "${@' '.join(sorted(set(d.getVar('AVAILABLE_LICENSES').split()) - set(d.getVar('COMPATIBLE_LICENSES').split())))}"
+                             
+      This will result in
+      INCOMPATIBLE_LICENSE
+      containing the names of all licences from
+      AVAILABLE_LICENSES
+      except the ones specified in
+      COMPATIBLE_LICENSES
+      , thus only allowing the latter licences to be used.
+INHERIT
+   Causes the named class or classes to be inherited globally. Anonymous
+   functions in the class or classes are not executed for the base
+   configuration and in each individual recipe. The OpenEmbedded build
+   system ignores changes to ``INHERIT`` in individual recipes.
+   For more information on ``INHERIT``, see the "```INHERIT``
+   Configuration
+   Directive <&YOCTO_DOCS_BB_URL;#inherit-configuration-directive>`__"
+   section in the Bitbake User Manual.
+INHERIT_DISTRO
+   Lists classes that will be inherited at the distribution level. It is
+   unlikely that you want to edit this variable.
+   The default value of the variable is set as follows in the
+   ``meta/conf/distro/defaultsetup.conf`` file: INHERIT_DISTRO ?=
+   "debian devshell sstate license"
+INHIBIT_DEFAULT_DEPS
+   Prevents the default dependencies, namely the C compiler and standard
+   C library (libc), from being added to ```DEPENDS`` <#var-DEPENDS>`__.
+   This variable is usually used within recipes that do not require any
+   compilation using the C compiler.
+   Set the variable to "1" to prevent the default dependencies from
+   being added.
+INHIBIT_PACKAGE_DEBUG_SPLIT
+   Prevents the OpenEmbedded build system from splitting out debug
+   information during packaging. By default, the build system splits out
+   debugging information during the
+   ```do_package`` <#ref-tasks-package>`__ task. For more information on
+   how debug information is split out, see the
+   ```PACKAGE_DEBUG_SPLIT_STYLE`` <#var-PACKAGE_DEBUG_SPLIT_STYLE>`__
+   variable.
+   To prevent the build system from splitting out debug information
+   during packaging, set the ``INHIBIT_PACKAGE_DEBUG_SPLIT`` variable as
+   follows: INHIBIT_PACKAGE_DEBUG_SPLIT = "1"
+INHIBIT_PACKAGE_STRIP
+   If set to "1", causes the build to not strip binaries in resulting
+   packages and prevents the ``-dbg`` package from containing the source
+   files.
+   By default, the OpenEmbedded build system strips binaries and puts
+   the debugging symbols into ``${``\ ```PN`` <#var-PN>`__\ ``}-dbg``.
+   Consequently, you should not set ``INHIBIT_PACKAGE_STRIP`` when you
+   plan to debug in general.
+INHIBIT_SYSROOT_STRIP
+   If set to "1", causes the build to not strip binaries in the
+   resulting sysroot.
+   By default, the OpenEmbedded build system strips binaries in the
+   resulting sysroot. When you specifically set the
+   ``INHIBIT_SYSROOT_STRIP`` variable to "1" in your recipe, you inhibit
+   this stripping.
+   If you want to use this variable, include the
+   ```staging`` <#ref-classes-staging>`__ class. This class uses a
+   ``sys_strip()`` function to test for the variable and acts
+   accordingly.
+   .. note::
+      Use of the
+      INHIBIT_SYSROOT_STRIP
+      variable occurs in rare and special circumstances. For example,
+      suppose you are building bare-metal firmware by using an external
+      GCC toolchain. Furthermore, even if the toolchain's binaries are
+      strippable, other files exist that are needed for the build that
+      are not strippable.
+INITRAMFS_FSTYPES
+   Defines the format for the output image of an initial RAM filesystem
+   (initramfs), which is used during boot. Supported formats are the
+   same as those supported by the
+   ```IMAGE_FSTYPES`` <#var-IMAGE_FSTYPES>`__ variable.
+   The default value of this variable, which is set in the
+   ``meta/conf/bitbake.conf`` configuration file in the `Source
+   Directory <#source-directory>`__, is "cpio.gz". The Linux kernel's
+   initramfs mechanism, as opposed to the initial RAM filesystem
+   `initrd <https://en.wikipedia.org/wiki/Initrd>`__ mechanism, expects
+   an optionally compressed cpio archive.
+INITRAMFS_IMAGE
+   Specifies the ```PROVIDES`` <#var-PROVIDES>`__ name of an image
+   recipe that is used to build an initial RAM filesystem (initramfs)
+   image. In other words, the ``INITRAMFS_IMAGE`` variable causes an
+   additional recipe to be built as a dependency to whatever root
+   filesystem recipe you might be using (e.g. ``core-image-sato``). The
+   initramfs image recipe you provide should set
+   ```IMAGE_FSTYPES`` <#var-IMAGE_FSTYPES>`__ to
+   ```INITRAMFS_FSTYPES`` <#var-INITRAMFS_FSTYPES>`__.
+   An initramfs image provides a temporary root filesystem used for
+   early system initialization (e.g. loading of modules needed to locate
+   and mount the "real" root filesystem).
+   .. note::
+      See the
+      meta/recipes-core/images/core-image-minimal-initramfs.bb
+      recipe in the
+      Source Directory
+      for an example initramfs recipe. To select this sample recipe as
+      the one built to provide the initramfs image, set
+      INITRAMFS_IMAGE
+      to "core-image-minimal-initramfs".
+   You can also find more information by referencing the
+   ``meta-poky/conf/local.conf.sample.extended`` configuration file in
+   the Source Directory, the ```image`` <#ref-classes-image>`__ class,
+   and the ```kernel`` <#ref-classes-kernel>`__ class to see how to use
+   the ``INITRAMFS_IMAGE`` variable.
+   If ``INITRAMFS_IMAGE`` is empty, which is the default, then no
+   initramfs image is built.
+   For more information, you can also see the
+   ```INITRAMFS_IMAGE_BUNDLE`` <#var-INITRAMFS_IMAGE_BUNDLE>`__
+   variable, which allows the generated image to be bundled inside the
+   kernel image. Additionally, for information on creating an initramfs
+   image, see the "`Building an Initial RAM Filesystem (initramfs)
+   Image <&YOCTO_DOCS_DEV_URL;#building-an-initramfs-image>`__" section
+   in the Yocto Project Development Tasks Manual.
+INITRAMFS_IMAGE_BUNDLE
+   Controls whether or not the image recipe specified by
+   ```INITRAMFS_IMAGE`` <#var-INITRAMFS_IMAGE>`__ is run through an
+   extra pass
+   (```do_bundle_initramfs`` <#ref-tasks-bundle_initramfs>`__) during
+   kernel compilation in order to build a single binary that contains
+   both the kernel image and the initial RAM filesystem (initramfs)
+   image. This makes use of the
+   ```CONFIG_INITRAMFS_SOURCE`` <#var-CONFIG_INITRAMFS_SOURCE>`__ kernel
+   feature.
+   .. note::
+      Using an extra compilation pass to bundle the initramfs avoids a
+      circular dependency between the kernel recipe and the initramfs
+      recipe should the initramfs include kernel modules. Should that be
+      the case, the initramfs recipe depends on the kernel for the
+      kernel modules, and the kernel depends on the initramfs recipe
+      since the initramfs is bundled inside the kernel image.
+   The combined binary is deposited into the ``tmp/deploy`` directory,
+   which is part of the `Build Directory <#build-directory>`__.
+   Setting the variable to "1" in a configuration file causes the
+   OpenEmbedded build system to generate a kernel image with the
+   initramfs specified in ``INITRAMFS_IMAGE`` bundled within:
+   INITRAMFS_IMAGE_BUNDLE = "1" By default, the
+   ```kernel`` <#ref-classes-kernel>`__ class sets this variable to a
+   null string as follows: INITRAMFS_IMAGE_BUNDLE ?= ""
+   .. note::
+      You must set the
+      INITRAMFS_IMAGE_BUNDLE
+      variable in a configuration file. You cannot set the variable in a
+      recipe file.
+   See the
+   ```local.conf.sample.extended`` <&YOCTO_GIT_URL;/cgit/cgit.cgi/poky/tree/meta-poky/conf/local.conf.sample.extended>`__
+   file for additional information. Also, for information on creating an
+   initramfs, see the "`Building an Initial RAM Filesystem (initramfs)
+   Image <&YOCTO_DOCS_DEV_URL;#building-an-initramfs-image>`__" section
+   in the Yocto Project Development Tasks Manual.
+INITRAMFS_LINK_NAME
+   The link name of the initial RAM filesystem image. This variable is
+   set in the ``meta/classes/kernel-artifact-names.bbclass`` file as
+   follows: INITRAMFS_LINK_NAME ?=
+   "initramfs-${KERNEL_ARTIFACT_LINK_NAME}" The value of the
+   ``KERNEL_ARTIFACT_LINK_NAME`` variable, which is set in the same
+   file, has the following value: KERNEL_ARTIFACT_LINK_NAME ?=
+   "${MACHINE}"
+   See the ```MACHINE`` <#var-MACHINE>`__ variable for additional
+   information.
+INITRAMFS_NAME
+   The base name of the initial RAM filesystem image. This variable is
+   set in the ``meta/classes/kernel-artifact-names.bbclass`` file as
+   follows: INITRAMFS_NAME ?= "initramfs-${KERNEL_ARTIFACT_NAME}" The
+   value of the ```KERNEL_ARTIFACT_NAME`` <#var-KERNEL_ARTIFACT_NAME>`__
+   variable, which is set in the same file, has the following value:
+   KERNEL_ARTIFACT_NAME ?=
+   "${PKGE}-${PKGV}-${PKGR}-${MACHINE}${IMAGE_VERSION_SUFFIX}"
+INITRD
+   Indicates list of filesystem images to concatenate and use as an
+   initial RAM disk (``initrd``).
+   The ``INITRD`` variable is an optional variable used with the
+   ```image-live`` <#ref-classes-image-live>`__ class.
+INITRD_IMAGE
+   When building a "live" bootable image (i.e. when
+   ```IMAGE_FSTYPES`` <#var-IMAGE_FSTYPES>`__ contains "live"),
+   ``INITRD_IMAGE`` specifies the image recipe that should be built to
+   provide the initial RAM disk image. The default value is
+   "core-image-minimal-initramfs".
+   See the ```image-live`` <#ref-classes-image-live>`__ class for more
+   information.
+INITSCRIPT_NAME
+   The filename of the initialization script as installed to
+   ``${sysconfdir}/init.d``.
+   This variable is used in recipes when using ``update-rc.d.bbclass``.
+   The variable is mandatory.
+INITSCRIPT_PACKAGES
+   A list of the packages that contain initscripts. If multiple packages
+   are specified, you need to append the package name to the other
+   ``INITSCRIPT_*`` as an override.
+   This variable is used in recipes when using ``update-rc.d.bbclass``.
+   The variable is optional and defaults to the ```PN`` <#var-PN>`__
+   variable.
+INITSCRIPT_PARAMS
+   Specifies the options to pass to ``update-rc.d``. Here is an example:
+   INITSCRIPT_PARAMS = "start 99 5 2 . stop 20 0 1 6 ."
+   In this example, the script has a runlevel of 99, starts the script
+   in initlevels 2 and 5, and stops the script in levels 0, 1 and 6.
+   The variable's default value is "defaults", which is set in the
+   ```update-rc.d`` <#ref-classes-update-rc.d>`__ class.
+   The value in ``INITSCRIPT_PARAMS`` is passed through to the
+   ``update-rc.d`` command. For more information on valid parameters,
+   please see the ``update-rc.d`` manual page at
+   ` <http://www.tin.org/bin/man.cgi?section=8&topic=update-rc.d>`__.
+INSANE_SKIP
+   Specifies the QA checks to skip for a specific package within a
+   recipe. For example, to skip the check for symbolic link ``.so``
+   files in the main package of a recipe, add the following to the
+   recipe. The package name override must be used, which in this example
+   is ``${PN}``: INSANE_SKIP_${PN} += "dev-so"
+   See the "```insane.bbclass`` <#ref-classes-insane>`__" section for a
+   list of the valid QA checks you can specify using this variable.
+INSTALL_TIMEZONE_FILE
+   By default, the ``tzdata`` recipe packages an ``/etc/timezone`` file.
+   Set the ``INSTALL_TIMEZONE_FILE`` variable to "0" at the
+   configuration level to disable this behavior.
+IPK_FEED_URIS
+   When the IPK backend is in use and package management is enabled on
+   the target, you can use this variable to set up ``opkg`` in the
+   target image to point to package feeds on a nominated server. Once
+   the feed is established, you can perform installations or upgrades
+   using the package manager at runtime.
+KARCH
+   Defines the kernel architecture used when assembling the
+   configuration. Architectures supported for this release are: powerpc
+   i386 x86_64 arm qemu mips
+   You define the ``KARCH`` variable in the `BSP
+   Descriptions <&YOCTO_DOCS_KERNEL_DEV_URL;#bsp-descriptions>`__.
+KBRANCH
+   A regular expression used by the build process to explicitly identify
+   the kernel branch that is validated, patched, and configured during a
+   build. You must set this variable to ensure the exact kernel branch
+   you want is being used by the build process.
+   Values for this variable are set in the kernel's recipe file and the
+   kernel's append file. For example, if you are using the
+   ``linux-yocto_4.12`` kernel, the kernel recipe file is the
+   ``meta/recipes-kernel/linux/linux-yocto_4.12.bb`` file. ``KBRANCH``
+   is set as follows in that kernel recipe file: KBRANCH ?=
+   "standard/base"
+   This variable is also used from the kernel's append file to identify
+   the kernel branch specific to a particular machine or target
+   hardware. Continuing with the previous kernel example, the kernel's
+   append file (i.e. ``linux-yocto_4.12.bbappend``) is located in the
+   BSP layer for a given machine. For example, the append file for the
+   Beaglebone, EdgeRouter, and generic versions of both 32 and 64-bit IA
+   machines (``meta-yocto-bsp``) is named
+   ``meta-yocto-bsp/recipes-kernel/linux/linux-yocto_4.12.bbappend``.
+   Here are the related statements from that append file:
+   KBRANCH_genericx86 = "standard/base" KBRANCH_genericx86-64 =
+   "standard/base" KBRANCH_edgerouter = "standard/edgerouter"
+   KBRANCH_beaglebone = "standard/beaglebone" The ``KBRANCH`` statements
+   identify the kernel branch to use when building for each supported
+   BSP.
+KBUILD_DEFCONFIG
+   When used with the ```kernel-yocto`` <#ref-classes-kernel-yocto>`__
+   class, specifies an "in-tree" kernel configuration file for use
+   during a kernel build.
+   Typically, when using a ``defconfig`` to configure a kernel during a
+   build, you place the file in your layer in the same manner as you
+   would place patch files and configuration fragment files (i.e.
+   "out-of-tree"). However, if you want to use a ``defconfig`` file that
+   is part of the kernel tree (i.e. "in-tree"), you can use the
+   ``KBUILD_DEFCONFIG`` variable and append the
+   ```KMACHINE`` <#var-KMACHINE>`__ variable to point to the
+   ``defconfig`` file.
+   To use the variable, set it in the append file for your kernel recipe
+   using the following form: KBUILD_DEFCONFIG_KMACHINE ?= defconfig_file
+   Here is an example from a "raspberrypi2" ``KMACHINE`` build that uses
+   a ``defconfig`` file named "bcm2709_defconfig":
+   KBUILD_DEFCONFIG_raspberrypi2 = "bcm2709_defconfig" As an
+   alternative, you can use the following within your append file:
+   KBUILD_DEFCONFIG_pn-linux-yocto ?= defconfig_file For more
+   information on how to use the ``KBUILD_DEFCONFIG`` variable, see the
+   "`Using an "In-Tree" ``defconfig``
+   File <&YOCTO_DOCS_KERNEL_DEV_URL;#using-an-in-tree-defconfig-file>`__"
+   section in the Yocto Project Linux Kernel Development Manual.
+KERNEL_ALT_IMAGETYPE
+   Specifies an alternate kernel image type for creation in addition to
+   the kernel image type specified using the
+   ```KERNEL_IMAGETYPE`` <#var-KERNEL_IMAGETYPE>`__ variable.
+KERNEL_ARTIFACT_NAME
+   Specifies the name of all of the build artifacts. You can change the
+   name of the artifacts by changing the ``KERNEL_ARTIFACT_NAME``
+   variable.
+   The value of ``KERNEL_ARTIFACT_NAME``, which is set in the
+   ``meta/classes/kernel-artifact-names.bbclass`` file, has the
+   following default value: KERNEL_ARTIFACT_NAME ?=
+   "${PKGE}-${PKGV}-${PKGR}-${MACHINE}${IMAGE_VERSION_SUFFIX}"
+   See the ```PKGE`` <#var-PKGE>`__, ```PKGV`` <#var-PKGV>`__,
+   ```PKGR`` <#var-PKGR>`__, and ```MACHINE`` <#var-MACHINE>`__
+   variables for additional information.
+   .. note::
+      The
+      IMAGE_VERSION_SUFFIX
+      variable is set to
+      DATETIME
+      .
+KERNEL_CLASSES
+   A list of classes defining kernel image types that the
+   ```kernel`` <#ref-classes-kernel>`__ class should inherit. You
+   typically append this variable to enable extended image types. An
+   example is the "kernel-fitimage", which enables fitImage support and
+   resides in ``meta/classes/kernel-fitimage.bbclass``. You can register
+   custom kernel image types with the ``kernel`` class using this
+   variable.
+KERNEL_DEVICETREE
+   Specifies the name of the generated Linux kernel device tree (i.e.
+   the ``.dtb``) file.
+   .. note::
+      Legacy support exists for specifying the full path to the device
+      tree. However, providing just the
+      .dtb
+      file is preferred.
+   In order to use this variable, the
+   ```kernel-devicetree`` <#ref-classes-kernel-devicetree>`__ class must
+   be inherited.
+KERNEL_DTB_LINK_NAME
+   The link name of the kernel device tree binary (DTB). This variable
+   is set in the ``meta/classes/kernel-artifact-names.bbclass`` file as
+   follows: KERNEL_DTB_LINK_NAME ?= "${KERNEL_ARTIFACT_LINK_NAME}" The
+   value of the ``KERNEL_ARTIFACT_LINK_NAME`` variable, which is set in
+   the same file, has the following value: KERNEL_ARTIFACT_LINK_NAME ?=
+   "${MACHINE}"
+   See the ```MACHINE`` <#var-MACHINE>`__ variable for additional
+   information.
+KERNEL_DTB_NAME
+   The base name of the kernel device tree binary (DTB). This variable
+   is set in the ``meta/classes/kernel-artifact-names.bbclass`` file as
+   follows: KERNEL_DTB_NAME ?= "${KERNEL_ARTIFACT_NAME}" The value of
+   the ```KERNEL_ARTIFACT_NAME`` <#var-KERNEL_ARTIFACT_NAME>`__
+   variable, which is set in the same file, has the following value:
+   KERNEL_ARTIFACT_NAME ?=
+   "${PKGE}-${PKGV}-${PKGR}-${MACHINE}${IMAGE_VERSION_SUFFIX}"
+KERNEL_EXTRA_ARGS
+   Specifies additional ``make`` command-line arguments the OpenEmbedded
+   build system passes on when compiling the kernel.
+KERNEL_FEATURES
+   Includes additional kernel metadata. In the OpenEmbedded build
+   system, the default Board Support Packages (BSPs)
+   `Metadata <#metadata>`__ is provided through the
+   ```KMACHINE`` <#var-KMACHINE>`__ and ```KBRANCH`` <#var-KBRANCH>`__
+   variables. You can use the ``KERNEL_FEATURES`` variable from within
+   the kernel recipe or kernel append file to further add metadata for
+   all BSPs or specific BSPs.
+   The metadata you add through this variable includes config fragments
+   and features descriptions, which usually includes patches as well as
+   config fragments. You typically override the ``KERNEL_FEATURES``
+   variable for a specific machine. In this way, you can provide
+   validated, but optional, sets of kernel configurations and features.
+   For example, the following example from the ``linux-yocto-rt_4.12``
+   kernel recipe adds "netfilter" and "taskstats" features to all BSPs
+   as well as "virtio" configurations to all QEMU machines. The last two
+   statements add specific configurations to targeted machine types:
+   KERNEL_EXTRA_FEATURES ?= "features/netfilter/netfilter.scc
+   features/taskstats/taskstats.scc" KERNEL_FEATURES_append = "
+   ${KERNEL_EXTRA_FEATURES}" KERNEL_FEATURES_append_qemuall = "
+   cfg/virtio.scc" KERNEL_FEATURES_append_qemux86 = " cfg/sound.scc
+   cfg/paravirt_kvm.scc" KERNEL_FEATURES_append_qemux86-64 = "
+   cfg/sound.scc"
+KERNEL_FIT_LINK_NAME
+   The link name of the kernel flattened image tree (FIT) image. This
+   variable is set in the ``meta/classes/kernel-artifact-names.bbclass``
+   file as follows: KERNEL_FIT_LINK_NAME ?=
+   "${KERNEL_ARTIFACT_LINK_NAME}" The value of the
+   ``KERNEL_ARTIFACT_LINK_NAME`` variable, which is set in the same
+   file, has the following value: KERNEL_ARTIFACT_LINK_NAME ?=
+   "${MACHINE}"
+   See the ```MACHINE`` <#var-MACHINE>`__ variable for additional
+   information.
+KERNEL_FIT_NAME
+   The base name of the kernel flattened image tree (FIT) image. This
+   variable is set in the ``meta/classes/kernel-artifact-names.bbclass``
+   file as follows: KERNEL_FIT_NAME ?= "${KERNEL_ARTIFACT_NAME}" The
+   value of the ```KERNEL_ARTIFACT_NAME`` <#var-KERNEL_ARTIFACT_NAME>`__
+   variable, which is set in the same file, has the following value:
+   KERNEL_ARTIFACT_NAME ?=
+   "${PKGE}-${PKGV}-${PKGR}-${MACHINE}${IMAGE_VERSION_SUFFIX}"
+KERNEL_IMAGE_LINK_NAME
+   The link name for the kernel image. This variable is set in the
+   ``meta/classes/kernel-artifact-names.bbclass`` file as follows:
+   KERNEL_IMAGE_LINK_NAME ?= "${KERNEL_ARTIFACT_LINK_NAME}" The value of
+   the ``KERNEL_ARTIFACT_LINK_NAME`` variable, which is set in the same
+   file, has the following value: KERNEL_ARTIFACT_LINK_NAME ?=
+   "${MACHINE}"
+   See the ```MACHINE`` <#var-MACHINE>`__ variable for additional
+   information.
+KERNEL_IMAGE_MAXSIZE
+   Specifies the maximum size of the kernel image file in kilobytes. If
+   ``KERNEL_IMAGE_MAXSIZE`` is set, the size of the kernel image file is
+   checked against the set value during the
+   ```do_sizecheck`` <#ref-tasks-sizecheck>`__ task. The task fails if
+   the kernel image file is larger than the setting.
+   ``KERNEL_IMAGE_MAXSIZE`` is useful for target devices that have a
+   limited amount of space in which the kernel image must be stored.
+   By default, this variable is not set, which means the size of the
+   kernel image is not checked.
+KERNEL_IMAGE_NAME
+   The base name of the kernel image. This variable is set in the
+   ``meta/classes/kernel-artifact-names.bbclass`` file as follows:
+   KERNEL_IMAGE_NAME ?= "${KERNEL_ARTIFACT_NAME}" The value of the
+   ```KERNEL_ARTIFACT_NAME`` <#var-KERNEL_ARTIFACT_NAME>`__ variable,
+   which is set in the same file, has the following value:
+   KERNEL_ARTIFACT_NAME ?=
+   "${PKGE}-${PKGV}-${PKGR}-${MACHINE}${IMAGE_VERSION_SUFFIX}"
+KERNEL_IMAGETYPE
+   The type of kernel to build for a device, usually set by the machine
+   configuration files and defaults to "zImage". This variable is used
+   when building the kernel and is passed to ``make`` as the target to
+   build.
+   If you want to build an alternate kernel image type, use the
+   ```KERNEL_ALT_IMAGETYPE`` <#var-KERNEL_ALT_IMAGETYPE>`__ variable.
+KERNEL_MODULE_AUTOLOAD
+   Lists kernel modules that need to be auto-loaded during boot.
+   .. note::
+      This variable replaces the deprecated
+      module_autoload
+      variable.
+   You can use the ``KERNEL_MODULE_AUTOLOAD`` variable anywhere that it
+   can be recognized by the kernel recipe or by an out-of-tree kernel
+   module recipe (e.g. a machine configuration file, a distribution
+   configuration file, an append file for the recipe, or the recipe
+   itself).
+   Specify it as follows: KERNEL_MODULE_AUTOLOAD += "module_name1
+   module_name2 module_name3"
+   Including ``KERNEL_MODULE_AUTOLOAD`` causes the OpenEmbedded build
+   system to populate the ``/etc/modules-load.d/modname.conf`` file with
+   the list of modules to be auto-loaded on boot. The modules appear
+   one-per-line in the file. Here is an example of the most common use
+   case: KERNEL_MODULE_AUTOLOAD += "module_name"
+   For information on how to populate the ``modname.conf`` file with
+   ``modprobe.d`` syntax lines, see the
+   ```KERNEL_MODULE_PROBECONF`` <#var-KERNEL_MODULE_PROBECONF>`__
+   variable.
+KERNEL_MODULE_PROBECONF
+   Provides a list of modules for which the OpenEmbedded build system
+   expects to find ``module_conf_``\ modname values that specify
+   configuration for each of the modules. For information on how to
+   provide those module configurations, see the
+   ```module_conf_*`` <#var-module_conf>`__ variable.
+KERNEL_PATH
+   The location of the kernel sources. This variable is set to the value
+   of the ```STAGING_KERNEL_DIR`` <#var-STAGING_KERNEL_DIR>`__ within
+   the ```module`` <#ref-classes-module>`__ class. For information on
+   how this variable is used, see the "`Incorporating Out-of-Tree
+   Modules <&YOCTO_DOCS_KERNEL_DEV_URL;#incorporating-out-of-tree-modules>`__"
+   section in the Yocto Project Linux Kernel Development Manual.
+   To help maximize compatibility with out-of-tree drivers used to build
+   modules, the OpenEmbedded build system also recognizes and uses the
+   ```KERNEL_SRC`` <#var-KERNEL_SRC>`__ variable, which is identical to
+   the ``KERNEL_PATH`` variable. Both variables are common variables
+   used by external Makefiles to point to the kernel source directory.
+KERNEL_SRC
+   The location of the kernel sources. This variable is set to the value
+   of the ```STAGING_KERNEL_DIR`` <#var-STAGING_KERNEL_DIR>`__ within
+   the ```module`` <#ref-classes-module>`__ class. For information on
+   how this variable is used, see the "`Incorporating Out-of-Tree
+   Modules <&YOCTO_DOCS_KERNEL_DEV_URL;#incorporating-out-of-tree-modules>`__"
+   section in the Yocto Project Linux Kernel Development Manual.
+   To help maximize compatibility with out-of-tree drivers used to build
+   modules, the OpenEmbedded build system also recognizes and uses the
+   ```KERNEL_PATH`` <#var-KERNEL_PATH>`__ variable, which is identical
+   to the ``KERNEL_SRC`` variable. Both variables are common variables
+   used by external Makefiles to point to the kernel source directory.
+KERNEL_VERSION
+   Specifies the version of the kernel as extracted from ``version.h``
+   or ``utsrelease.h`` within the kernel sources. Effects of setting
+   this variable do not take affect until the kernel has been
+   configured. Consequently, attempting to refer to this variable in
+   contexts prior to configuration will not work.
+KERNELDEPMODDEPEND
+   Specifies whether the data referenced through
+   ```PKGDATA_DIR`` <#var-PKGDATA_DIR>`__ is needed or not. The
+   ``KERNELDEPMODDEPEND`` does not control whether or not that data
+   exists, but simply whether or not it is used. If you do not need to
+   use the data, set the ``KERNELDEPMODDEPEND`` variable in your
+   ``initramfs`` recipe. Setting the variable there when the data is not
+   needed avoids a potential dependency loop.
+KFEATURE_DESCRIPTION
+   Provides a short description of a configuration fragment. You use
+   this variable in the ``.scc`` file that describes a configuration
+   fragment file. Here is the variable used in a file named ``smp.scc``
+   to describe SMP being enabled: define KFEATURE_DESCRIPTION "Enable
+   SMP"
+KMACHINE
+   The machine as known by the kernel. Sometimes the machine name used
+   by the kernel does not match the machine name used by the
+   OpenEmbedded build system. For example, the machine name that the
+   OpenEmbedded build system understands as ``core2-32-intel-common``
+   goes by a different name in the Linux Yocto kernel. The kernel
+   understands that machine as ``intel-core2-32``. For cases like these,
+   the ``KMACHINE`` variable maps the kernel machine name to the
+   OpenEmbedded build system machine name.
+   These mappings between different names occur in the Yocto Linux
+   Kernel's ``meta`` branch. As an example take a look in the
+   ``common/recipes-kernel/linux/linux-yocto_3.19.bbappend`` file:
+   LINUX_VERSION_core2-32-intel-common = "3.19.0"
+   COMPATIBLE_MACHINE_core2-32-intel-common = "${MACHINE}"
+   SRCREV_meta_core2-32-intel-common =
+   "8897ef68b30e7426bc1d39895e71fb155d694974"
+   SRCREV_machine_core2-32-intel-common =
+   "43b9eced9ba8a57add36af07736344dcc383f711"
+   KMACHINE_core2-32-intel-common = "intel-core2-32"
+   KBRANCH_core2-32-intel-common = "standard/base"
+   KERNEL_FEATURES_append_core2-32-intel-common =
+   "${KERNEL_FEATURES_INTEL_COMMON}" The ``KMACHINE`` statement says
+   that the kernel understands the machine name as "intel-core2-32".
+   However, the OpenEmbedded build system understands the machine as
+   "core2-32-intel-common".
+KTYPE
+   Defines the kernel type to be used in assembling the configuration.
+   The linux-yocto recipes define "standard", "tiny", and "preempt-rt"
+   kernel types. See the "`Kernel
+   Types <&YOCTO_DOCS_KERNEL_DEV_URL;#kernel-types>`__" section in the
+   Yocto Project Linux Kernel Development Manual for more information on
+   kernel types.
+   You define the ``KTYPE`` variable in the `BSP
+   Descriptions <&YOCTO_DOCS_KERNEL_DEV_URL;#bsp-descriptions>`__. The
+   value you use must match the value used for the
+   ```LINUX_KERNEL_TYPE`` <#var-LINUX_KERNEL_TYPE>`__ value used by the
+   kernel recipe.
+LABELS
+   Provides a list of targets for automatic configuration.
+   See the ```grub-efi`` <#ref-classes-grub-efi>`__ class for more
+   information on how this variable is used.
+LAYERDEPENDS
+   Lists the layers, separated by spaces, on which this recipe depends.
+   Optionally, you can specify a specific layer version for a dependency
+   by adding it to the end of the layer name. Here is an example:
+   LAYERDEPENDS_mylayer = "anotherlayer (=3)" In this previous example,
+   version 3 of "anotherlayer" is compared against
+   ```LAYERVERSION`` <#var-LAYERVERSION>`__\ ``_anotherlayer``.
+   An error is produced if any dependency is missing or the version
+   numbers (if specified) do not match exactly. This variable is used in
+   the ``conf/layer.conf`` file and must be suffixed with the name of
+   the specific layer (e.g. ``LAYERDEPENDS_mylayer``).
+LAYERDIR
+   When used inside the ``layer.conf`` configuration file, this variable
+   provides the path of the current layer. This variable is not
+   available outside of ``layer.conf`` and references are expanded
+   immediately when parsing of the file completes.
+LAYERRECOMMENDS
+   Lists the layers, separated by spaces, recommended for use with this
+   layer.
+   Optionally, you can specify a specific layer version for a
+   recommendation by adding the version to the end of the layer name.
+   Here is an example: LAYERRECOMMENDS_mylayer = "anotherlayer (=3)" In
+   this previous example, version 3 of "anotherlayer" is compared
+   against ``LAYERVERSION_anotherlayer``.
+   This variable is used in the ``conf/layer.conf`` file and must be
+   suffixed with the name of the specific layer (e.g.
+   ``LAYERRECOMMENDS_mylayer``).
+LAYERSERIES_COMPAT
+   Lists the versions of the `OpenEmbedded-Core <#oe-core>`__ for which
+   a layer is compatible. Using the ``LAYERSERIES_COMPAT`` variable
+   allows the layer maintainer to indicate which combinations of the
+   layer and OE-Core can be expected to work. The variable gives the
+   system a way to detect when a layer has not been tested with new
+   releases of OE-Core (e.g. the layer is not maintained).
+   To specify the OE-Core versions for which a layer is compatible, use
+   this variable in your layer's ``conf/layer.conf`` configuration file.
+   For the list, use the Yocto Project `Release
+   Name <https://wiki.yoctoproject.org/wiki/Releases>`__ (e.g.
+   DISTRO_NAME_NO_CAP). To specify multiple OE-Core versions for the
+   layer, use a space-separated list: LAYERSERIES_COMPAT_layer_root_name
+   = "DISTRO_NAME_NO_CAP DISTRO_NAME_NO_CAP_MINUS_ONE"
+   .. note::
+      Setting
+      LAYERSERIES_COMPAT
+      is required by the Yocto Project Compatible version 2 standard.
+      The OpenEmbedded build system produces a warning if the variable
+      is not set for any given layer.
+   See the "`Creating Your Own
+   Layer <&YOCTO_DOCS_DEV_URL;#creating-your-own-layer>`__" section in
+   the Yocto Project Development Tasks Manual.
+LAYERVERSION
+   Optionally specifies the version of a layer as a single number. You
+   can use this within ```LAYERDEPENDS`` <#var-LAYERDEPENDS>`__ for
+   another layer in order to depend on a specific version of the layer.
+   This variable is used in the ``conf/layer.conf`` file and must be
+   suffixed with the name of the specific layer (e.g.
+   ``LAYERVERSION_mylayer``).
+LD
+   The minimal command and arguments used to run the linker.
+LDFLAGS
+   Specifies the flags to pass to the linker. This variable is exported
+   to an environment variable and thus made visible to the software
+   being built during the compilation step.
+   Default initialization for ``LDFLAGS`` varies depending on what is
+   being built:
+   -  ```TARGET_LDFLAGS`` <#var-TARGET_LDFLAGS>`__ when building for the
+      target
+   -  ```BUILD_LDFLAGS`` <#var-BUILD_LDFLAGS>`__ when building for the
+      build host (i.e. ``-native``)
+   -  ```BUILDSDK_LDFLAGS`` <#var-BUILDSDK_LDFLAGS>`__ when building for
+      an SDK (i.e. ``nativesdk-``)
+LEAD_SONAME
+   Specifies the lead (or primary) compiled library file (i.e. ``.so``)
+   that the ```debian`` <#ref-classes-debian>`__ class applies its
+   naming policy to given a recipe that packages multiple libraries.
+   This variable works in conjunction with the ``debian`` class.
+LIC_FILES_CHKSUM
+   Checksums of the license text in the recipe source code.
+   This variable tracks changes in license text of the source code
+   files. If the license text is changed, it will trigger a build
+   failure, which gives the developer an opportunity to review any
+   license change.
+   This variable must be defined for all recipes (unless
+   ```LICENSE`` <#var-LICENSE>`__ is set to "CLOSED").
+   For more information, see the "`Tracking License
+   Changes <&YOCTO_DOCS_DEV_URL;#usingpoky-configuring-LIC_FILES_CHKSUM>`__"
+   section in the Yocto Project Development Tasks Manual.
+LICENSE
+   The list of source licenses for the recipe. Follow these rules:
+   -  Do not use spaces within individual license names.
+   -  Separate license names using \| (pipe) when there is a choice
+      between licenses.
+   -  Separate license names using & (ampersand) when multiple licenses
+      exist that cover different parts of the source.
+   -  You can use spaces between license names.
+   -  For standard licenses, use the names of the files in
+      ``meta/files/common-licenses/`` or the
+      ```SPDXLICENSEMAP`` <#var-SPDXLICENSEMAP>`__ flag names defined in
+      ``meta/conf/licenses.conf``.
+   Here are some examples: LICENSE = "LGPLv2.1 \| GPLv3" LICENSE =
+   "MPL-1 & LGPLv2.1" LICENSE = "GPLv2+" The first example is from the
+   recipes for Qt, which the user may choose to distribute under either
+   the LGPL version 2.1 or GPL version 3. The second example is from
+   Cairo where two licenses cover different parts of the source code.
+   The final example is from ``sysstat``, which presents a single
+   license.
+   You can also specify licenses on a per-package basis to handle
+   situations where components of the output have different licenses.
+   For example, a piece of software whose code is licensed under GPLv2
+   but has accompanying documentation licensed under the GNU Free
+   Documentation License 1.2 could be specified as follows: LICENSE =
+   "GFDL-1.2 & GPLv2" LICENSE_${PN} = "GPLv2" LICENSE_${PN}-doc =
+   "GFDL-1.2"
+LICENSE_CREATE_PACKAGE
+   Setting ``LICENSE_CREATE_PACKAGE`` to "1" causes the OpenEmbedded
+   build system to create an extra package (i.e.
+   ``${``\ ```PN`` <#var-PN>`__\ ``}-lic``) for each recipe and to add
+   those packages to the
+   ```RRECOMMENDS`` <#var-RRECOMMENDS>`__\ ``_${PN}``.
+   The ``${PN}-lic`` package installs a directory in
+   ``/usr/share/licenses`` named ``${PN}``, which is the recipe's base
+   name, and installs files in that directory that contain license and
+   copyright information (i.e. copies of the appropriate license files
+   from ``meta/common-licenses`` that match the licenses specified in
+   the ```LICENSE`` <#var-LICENSE>`__ variable of the recipe metadata
+   and copies of files marked in
+   ```LIC_FILES_CHKSUM`` <#var-LIC_FILES_CHKSUM>`__ as containing
+   license text).
+   For related information on providing license text, see the
+   ```COPY_LIC_DIRS`` <#var-COPY_LIC_DIRS>`__ variable, the
+   ```COPY_LIC_MANIFEST`` <#var-COPY_LIC_MANIFEST>`__ variable, and the
+   "`Providing License
+   Text <&YOCTO_DOCS_DEV_URL;#providing-license-text>`__" section in the
+   Yocto Project Development Tasks Manual.
+LICENSE_FLAGS
+   Specifies additional flags for a recipe you must whitelist through
+   ```LICENSE_FLAGS_WHITELIST`` <#var-LICENSE_FLAGS_WHITELIST>`__ in
+   order to allow the recipe to be built. When providing multiple flags,
+   separate them with spaces.
+   This value is independent of ```LICENSE`` <#var-LICENSE>`__ and is
+   typically used to mark recipes that might require additional licenses
+   in order to be used in a commercial product. For more information,
+   see the "`Enabling Commercially Licensed
+   Recipes <&YOCTO_DOCS_DEV_URL;#enabling-commercially-licensed-recipes>`__"
+   section in the Yocto Project Development Tasks Manual.
+LICENSE_FLAGS_WHITELIST
+   Lists license flags that when specified in
+   ```LICENSE_FLAGS`` <#var-LICENSE_FLAGS>`__ within a recipe should not
+   prevent that recipe from being built. This practice is otherwise
+   known as "whitelisting" license flags. For more information, see the
+   "`Enabling Commercially Licensed
+   Recipes <&YOCTO_DOCS_DEV_URL;#enabling-commercially-licensed-recipes>`__"
+   section in the Yocto Project Development Tasks Manual.
+LICENSE_PATH
+   Path to additional licenses used during the build. By default, the
+   OpenEmbedded build system uses ``COMMON_LICENSE_DIR`` to define the
+   directory that holds common license text used during the build. The
+   ``LICENSE_PATH`` variable allows you to extend that location to other
+   areas that have additional licenses: LICENSE_PATH +=
+   "path-to-additional-common-licenses"
+LINUX_KERNEL_TYPE
+   Defines the kernel type to be used in assembling the configuration.
+   The linux-yocto recipes define "standard", "tiny", and "preempt-rt"
+   kernel types. See the "`Kernel
+   Types <&YOCTO_DOCS_KERNEL_DEV_URL;#kernel-types>`__" section in the
+   Yocto Project Linux Kernel Development Manual for more information on
+   kernel types.
+   If you do not specify a ``LINUX_KERNEL_TYPE``, it defaults to
+   "standard". Together with ```KMACHINE`` <#var-KMACHINE>`__, the
+   ``LINUX_KERNEL_TYPE`` variable defines the search arguments used by
+   the kernel tools to find the appropriate description within the
+   kernel `Metadata <#metadata>`__ with which to build out the sources
+   and configuration.
+LINUX_VERSION
+   The Linux version from ``kernel.org`` on which the Linux kernel image
+   being built using the OpenEmbedded build system is based. You define
+   this variable in the kernel recipe. For example, the
+   ``linux-yocto-3.4.bb`` kernel recipe found in
+   ``meta/recipes-kernel/linux`` defines the variables as follows:
+   LINUX_VERSION ?= "3.4.24"
+   The ``LINUX_VERSION`` variable is used to define ```PV`` <#var-PV>`__
+   for the recipe: PV = "${LINUX_VERSION}+git${SRCPV}"
+LINUX_VERSION_EXTENSION
+   A string extension compiled into the version string of the Linux
+   kernel built with the OpenEmbedded build system. You define this
+   variable in the kernel recipe. For example, the linux-yocto kernel
+   recipes all define the variable as follows: LINUX_VERSION_EXTENSION
+   ?= "-yocto-${`LINUX_KERNEL_TYPE <#var-LINUX_KERNEL_TYPE>`__}"
+   Defining this variable essentially sets the Linux kernel
+   configuration item ``CONFIG_LOCALVERSION``, which is visible through
+   the ``uname`` command. Here is an example that shows the extension
+   assuming it was set as previously shown: $ uname -r 3.7.0-rc8-custom
+LOG_DIR
+   Specifies the directory to which the OpenEmbedded build system writes
+   overall log files. The default directory is ``${TMPDIR}/log``.
+   For the directory containing logs specific to each task, see the
+   ```T`` <#var-T>`__ variable.
+MACHINE
+   Specifies the target device for which the image is built. You define
+   ``MACHINE`` in the ``local.conf`` file found in the `Build
+   Directory <#build-directory>`__. By default, ``MACHINE`` is set to
+   "qemux86", which is an x86-based architecture machine to be emulated
+   using QEMU: MACHINE ?= "qemux86"
+   The variable corresponds to a machine configuration file of the same
+   name, through which machine-specific configurations are set. Thus,
+   when ``MACHINE`` is set to "qemux86" there exists the corresponding
+   ``qemux86.conf`` machine configuration file, which can be found in
+   the `Source Directory <#source-directory>`__ in
+   ``meta/conf/machine``.
+   The list of machines supported by the Yocto Project as shipped
+   include the following: MACHINE ?= "qemuarm" MACHINE ?= "qemuarm64"
+   MACHINE ?= "qemumips" MACHINE ?= "qemumips64" MACHINE ?= "qemuppc"
+   MACHINE ?= "qemux86" MACHINE ?= "qemux86-64" MACHINE ?= "genericx86"
+   MACHINE ?= "genericx86-64" MACHINE ?= "beaglebone" MACHINE ?=
+   "edgerouter" The last five are Yocto Project reference hardware
+   boards, which are provided in the ``meta-yocto-bsp`` layer.
+   .. note::
+      Adding additional Board Support Package (BSP) layers to your
+      configuration adds new possible settings for
+      MACHINE
+      .
+MACHINE_ARCH
+   Specifies the name of the machine-specific architecture. This
+   variable is set automatically from ```MACHINE`` <#var-MACHINE>`__ or
+   ```TUNE_PKGARCH`` <#var-TUNE_PKGARCH>`__. You should not hand-edit
+   the ``MACHINE_ARCH`` variable.
+MACHINE_ESSENTIAL_EXTRA_RDEPENDS
+   A list of required machine-specific packages to install as part of
+   the image being built. The build process depends on these packages
+   being present. Furthermore, because this is a "machine-essential"
+   variable, the list of packages are essential for the machine to boot.
+   The impact of this variable affects images based on
+   ``packagegroup-core-boot``, including the ``core-image-minimal``
+   image.
+   This variable is similar to the
+   ``MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS`` variable with the exception
+   that the image being built has a build dependency on the variable's
+   list of packages. In other words, the image will not build if a file
+   in this list is not found.
+   As an example, suppose the machine for which you are building
+   requires ``example-init`` to be run during boot to initialize the
+   hardware. In this case, you would use the following in the machine's
+   ``.conf`` configuration file: MACHINE_ESSENTIAL_EXTRA_RDEPENDS +=
+   "example-init"
+MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS
+   A list of recommended machine-specific packages to install as part of
+   the image being built. The build process does not depend on these
+   packages being present. However, because this is a
+   "machine-essential" variable, the list of packages are essential for
+   the machine to boot. The impact of this variable affects images based
+   on ``packagegroup-core-boot``, including the ``core-image-minimal``
+   image.
+   This variable is similar to the ``MACHINE_ESSENTIAL_EXTRA_RDEPENDS``
+   variable with the exception that the image being built does not have
+   a build dependency on the variable's list of packages. In other
+   words, the image will still build if a package in this list is not
+   found. Typically, this variable is used to handle essential kernel
+   modules, whose functionality may be selected to be built into the
+   kernel rather than as a module, in which case a package will not be
+   produced.
+   Consider an example where you have a custom kernel where a specific
+   touchscreen driver is required for the machine to be usable. However,
+   the driver can be built as a module or into the kernel depending on
+   the kernel configuration. If the driver is built as a module, you
+   want it to be installed. But, when the driver is built into the
+   kernel, you still want the build to succeed. This variable sets up a
+   "recommends" relationship so that in the latter case, the build will
+   not fail due to the missing package. To accomplish this, assuming the
+   package for the module was called ``kernel-module-ab123``, you would
+   use the following in the machine's ``.conf`` configuration file:
+   MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS += "kernel-module-ab123"
+   .. note::
+      In this example, the
+      kernel-module-ab123
+      recipe needs to explicitly set its
+      PACKAGES
+      variable to ensure that BitBake does not use the kernel recipe's
+      PACKAGES_DYNAMIC
+      variable to satisfy the dependency.
+   Some examples of these machine essentials are flash, screen,
+   keyboard, mouse, or touchscreen drivers (depending on the machine).
+MACHINE_EXTRA_RDEPENDS
+   A list of machine-specific packages to install as part of the image
+   being built that are not essential for the machine to boot. However,
+   the build process for more fully-featured images depends on the
+   packages being present.
+   This variable affects all images based on ``packagegroup-base``,
+   which does not include the ``core-image-minimal`` or
+   ``core-image-full-cmdline`` images.
+   The variable is similar to the ``MACHINE_EXTRA_RRECOMMENDS`` variable
+   with the exception that the image being built has a build dependency
+   on the variable's list of packages. In other words, the image will
+   not build if a file in this list is not found.
+   An example is a machine that has WiFi capability but is not essential
+   for the machine to boot the image. However, if you are building a
+   more fully-featured image, you want to enable the WiFi. The package
+   containing the firmware for the WiFi hardware is always expected to
+   exist, so it is acceptable for the build process to depend upon
+   finding the package. In this case, assuming the package for the
+   firmware was called ``wifidriver-firmware``, you would use the
+   following in the ``.conf`` file for the machine:
+   MACHINE_EXTRA_RDEPENDS += "wifidriver-firmware"
+MACHINE_EXTRA_RRECOMMENDS
+   A list of machine-specific packages to install as part of the image
+   being built that are not essential for booting the machine. The image
+   being built has no build dependency on this list of packages.
+   This variable affects only images based on ``packagegroup-base``,
+   which does not include the ``core-image-minimal`` or
+   ``core-image-full-cmdline`` images.
+   This variable is similar to the ``MACHINE_EXTRA_RDEPENDS`` variable
+   with the exception that the image being built does not have a build
+   dependency on the variable's list of packages. In other words, the
+   image will build if a file in this list is not found.
+   An example is a machine that has WiFi capability but is not essential
+   For the machine to boot the image. However, if you are building a
+   more fully-featured image, you want to enable WiFi. In this case, the
+   package containing the WiFi kernel module will not be produced if the
+   WiFi driver is built into the kernel, in which case you still want
+   the build to succeed instead of failing as a result of the package
+   not being found. To accomplish this, assuming the package for the
+   module was called ``kernel-module-examplewifi``, you would use the
+   following in the ``.conf`` file for the machine:
+   MACHINE_EXTRA_RRECOMMENDS += "kernel-module-examplewifi"
+MACHINE_FEATURES
+   Specifies the list of hardware features the
+   ```MACHINE`` <#var-MACHINE>`__ is capable of supporting. For related
+   information on enabling features, see the
+   ```DISTRO_FEATURES`` <#var-DISTRO_FEATURES>`__,
+   ```COMBINED_FEATURES`` <#var-COMBINED_FEATURES>`__, and
+   ```IMAGE_FEATURES`` <#var-IMAGE_FEATURES>`__ variables.
+   For a list of hardware features supported by the Yocto Project as
+   shipped, see the "`Machine Features <#ref-features-machine>`__"
+   section.
+MACHINE_FEATURES_BACKFILL
+   Features to be added to ``MACHINE_FEATURES`` if not also present in
+   ``MACHINE_FEATURES_BACKFILL_CONSIDERED``.
+   This variable is set in the ``meta/conf/bitbake.conf`` file. It is
+   not intended to be user-configurable. It is best to just reference
+   the variable to see which machine features are being backfilled for
+   all machine configurations. See the "`Feature
+   Backfilling <#ref-features-backfill>`__" section for more
+   information.
+MACHINE_FEATURES_BACKFILL_CONSIDERED
+   Features from ``MACHINE_FEATURES_BACKFILL`` that should not be
+   backfilled (i.e. added to ``MACHINE_FEATURES``) during the build. See
+   the "`Feature Backfilling <#ref-features-backfill>`__" section for
+   more information.
+MACHINEOVERRIDES
+   A colon-separated list of overrides that apply to the current
+   machine. By default, this list includes the value of
+   ```MACHINE`` <#var-MACHINE>`__.
+   You can extend ``MACHINEOVERRIDES`` to add extra overrides that
+   should apply to a machine. For example, all machines emulated in QEMU
+   (e.g. ``qemuarm``, ``qemux86``, and so forth) include a file named
+   ``meta/conf/machine/include/qemu.inc`` that prepends the following
+   override to ``MACHINEOVERRIDES``: MACHINEOVERRIDES =. "qemuall:" This
+   override allows variables to be overriden for all machines emulated
+   in QEMU, like in the following example from the ``connman-conf``
+   recipe: SRC_URI_append_qemuall = "file://wired.config \\
+   file://wired-setup \\ " The underlying mechanism behind
+   ``MACHINEOVERRIDES`` is simply that it is included in the default
+   value of ```OVERRIDES`` <#var-OVERRIDES>`__.
+MAINTAINER
+   The email address of the distribution maintainer.
+MIRRORS
+   Specifies additional paths from which the OpenEmbedded build system
+   gets source code. When the build system searches for source code, it
+   first tries the local download directory. If that location fails, the
+   build system tries locations defined by
+   ```PREMIRRORS`` <#var-PREMIRRORS>`__, the upstream source, and then
+   locations specified by ``MIRRORS`` in that order.
+   Assuming your distribution (```DISTRO`` <#var-DISTRO>`__) is "poky",
+   the default value for ``MIRRORS`` is defined in the
+   ``conf/distro/poky.conf`` file in the ``meta-poky`` Git repository.
+MLPREFIX
+   Specifies a prefix has been added to ```PN`` <#var-PN>`__ to create a
+   special version of a recipe or package (i.e. a Multilib version). The
+   variable is used in places where the prefix needs to be added to or
+   removed from a the name (e.g. the ```BPN`` <#var-BPN>`__ variable).
+   ``MLPREFIX`` gets set when a prefix has been added to ``PN``.
+   .. note::
+      The "ML" in
+      MLPREFIX
+      stands for "MultiLib". This representation is historical and comes
+      from a time when
+      nativesdk
+      was a suffix rather than a prefix on the recipe name. When
+      nativesdk
+      was turned into a prefix, it made sense to set
+      MLPREFIX
+      for it as well.
+   To help understand when ``MLPREFIX`` might be needed, consider when
+   ```BBCLASSEXTEND`` <#var-BBCLASSEXTEND>`__ is used to provide a
+   ``nativesdk`` version of a recipe in addition to the target version.
+   If that recipe declares build-time dependencies on tasks in other
+   recipes by using ```DEPENDS`` <#var-DEPENDS>`__, then a dependency on
+   "foo" will automatically get rewritten to a dependency on
+   "nativesdk-foo". However, dependencies like the following will not
+   get rewritten automatically: do_foo[depends] += "recipe:do_foo" If
+   you want such a dependency to also get transformed, you can do the
+   following: do_foo[depends] += "${MLPREFIX}recipe:do_foo"
+module_autoload
+   This variable has been replaced by the ``KERNEL_MODULE_AUTOLOAD``
+   variable. You should replace all occurrences of ``module_autoload``
+   with additions to ``KERNEL_MODULE_AUTOLOAD``, for example:
+   module_autoload_rfcomm = "rfcomm"
+   should now be replaced with: KERNEL_MODULE_AUTOLOAD += "rfcomm" See
+   the ```KERNEL_MODULE_AUTOLOAD`` <#var-KERNEL_MODULE_AUTOLOAD>`__
+   variable for more information.
+module_conf
+   Specifies ```modprobe.d`` <http://linux.die.net/man/5/modprobe.d>`__
+   syntax lines for inclusion in the ``/etc/modprobe.d/modname.conf``
+   file.
+   You can use this variable anywhere that it can be recognized by the
+   kernel recipe or out-of-tree kernel module recipe (e.g. a machine
+   configuration file, a distribution configuration file, an append file
+   for the recipe, or the recipe itself). If you use this variable, you
+   must also be sure to list the module name in the
+   ```KERNEL_MODULE_AUTOLOAD`` <#var-KERNEL_MODULE_AUTOLOAD>`__
+   variable.
+   Here is the general syntax: module_conf_module_name =
+   "modprobe.d-syntax" You must use the kernel module name override.
+   Run ``man modprobe.d`` in the shell to find out more information on
+   the exact syntax you want to provide with ``module_conf``.
+   Including ``module_conf`` causes the OpenEmbedded build system to
+   populate the ``/etc/modprobe.d/modname.conf`` file with
+   ``modprobe.d`` syntax lines. Here is an example that adds the options
+   ``arg1`` and ``arg2`` to a module named ``mymodule``:
+   module_conf_mymodule = "options mymodule arg1=val1 arg2=val2"
+   For information on how to specify kernel modules to auto-load on
+   boot, see the
+   ```KERNEL_MODULE_AUTOLOAD`` <#var-KERNEL_MODULE_AUTOLOAD>`__
+   variable.
+MODULE_TARBALL_DEPLOY
+   Controls creation of the ``modules-*.tgz`` file. Set this variable to
+   "0" to disable creation of this file, which contains all of the
+   kernel modules resulting from a kernel build.
+MODULE_TARBALL_LINK_NAME
+   The link name of the kernel module tarball. This variable is set in
+   the ``meta/classes/kernel-artifact-names.bbclass`` file as follows:
+   MODULE_TARBALL_LINK_NAME ?= "${KERNEL_ARTIFACT_LINK_NAME}" The value
+   of the ``KERNEL_ARTIFACT_LINK_NAME`` variable, which is set in the
+   same file, has the following value: KERNEL_ARTIFACT_LINK_NAME ?=
+   "${MACHINE}"
+   See the ```MACHINE`` <#var-MACHINE>`__ variable for additional
+   information.
+MODULE_TARBALL_NAME
+   The base name of the kernel module tarball. This variable is set in
+   the ``meta/classes/kernel-artifact-names.bbclass`` file as follows:
+   MODULE_TARBALL_NAME ?= "${KERNEL_ARTIFACT_NAME}" The value of the
+   ```KERNEL_ARTIFACT_NAME`` <#var-KERNEL_ARTIFACT_NAME>`__ variable,
+   which is set in the same file, has the following value:
+   KERNEL_ARTIFACT_NAME ?=
+   "${PKGE}-${PKGV}-${PKGR}-${MACHINE}${IMAGE_VERSION_SUFFIX}"
+MULTIMACH_TARGET_SYS
+   Uniquely identifies the type of the target system for which packages
+   are being built. This variable allows output for different types of
+   target systems to be put into different subdirectories of the same
+   output directory.
+   The default value of this variable is:
+   ${PACKAGE_ARCH}${TARGET_VENDOR}-${TARGET_OS} Some classes (e.g.
+   ```cross-canadian`` <#ref-classes-cross-canadian>`__) modify the
+   ``MULTIMACH_TARGET_SYS`` value.
+   See the ```STAMP`` <#var-STAMP>`__ variable for an example. See the
+   ```STAGING_DIR_TARGET`` <#var-STAGING_DIR_TARGET>`__ variable for
+   more information.
+NATIVELSBSTRING
+   A string identifying the host distribution. Strings consist of the
+   host distributor ID followed by the release, as reported by the
+   ``lsb_release`` tool or as read from ``/etc/lsb-release``. For
+   example, when running a build on Ubuntu 12.10, the value is
+   "Ubuntu-12.10". If this information is unable to be determined, the
+   value resolves to "Unknown".
+   This variable is used by default to isolate native shared state
+   packages for different distributions (e.g. to avoid problems with
+   ``glibc`` version incompatibilities). Additionally, the variable is
+   checked against
+   ```SANITY_TESTED_DISTROS`` <#var-SANITY_TESTED_DISTROS>`__ if that
+   variable is set.
+NM
+   The minimal command and arguments to run ``nm``.
+NO_GENERIC_LICENSE
+   Avoids QA errors when you use a non-common, non-CLOSED license in a
+   recipe. Packages exist, such as the linux-firmware package, with many
+   licenses that are not in any way common. Also, new licenses are added
+   occasionally to avoid introducing a lot of common license files,
+   which are only applicable to a specific package.
+   ``NO_GENERIC_LICENSE`` is used to allow copying a license that does
+   not exist in common licenses.
+   The following example shows how to add ``NO_GENERIC_LICENSE`` to a
+   recipe: NO_GENERIC_LICENSE[license_name] =
+   "license_file_in_fetched_source" The following is an example that
+   uses the ``LICENSE.Abilis.txt`` file as the license from the fetched
+   source: NO_GENERIC_LICENSE[Firmware-Abilis] = "LICENSE.Abilis.txt"
+NO_RECOMMENDATIONS
+   Prevents installation of all "recommended-only" packages.
+   Recommended-only packages are packages installed only through the
+   ```RRECOMMENDS`` <#var-RRECOMMENDS>`__ variable). Setting the
+   ``NO_RECOMMENDATIONS`` variable to "1" turns this feature on:
+   NO_RECOMMENDATIONS = "1"
+   You can set this variable globally in your ``local.conf`` file or you
+   can attach it to a specific image recipe by using the recipe name
+   override: NO_RECOMMENDATIONS_pn-target_image = "1"
+   It is important to realize that if you choose to not install packages
+   using this variable and some other packages are dependent on them
+   (i.e. listed in a recipe's ```RDEPENDS`` <#var-RDEPENDS>`__
+   variable), the OpenEmbedded build system ignores your request and
+   will install the packages to avoid dependency errors.
+   .. note::
+      Some recommended packages might be required for certain system
+      functionality, such as kernel modules. It is up to you to add
+      packages with the
+      IMAGE_INSTALL
+      variable.
+   Support for this variable exists only when using the IPK and RPM
+   packaging backend. Support does not exist for DEB.
+   See the ```BAD_RECOMMENDATIONS`` <#var-BAD_RECOMMENDATIONS>`__ and
+   the ```PACKAGE_EXCLUDE`` <#var-PACKAGE_EXCLUDE>`__ variables for
+   related information.
+NOAUTOPACKAGEDEBUG
+   Disables auto package from splitting ``.debug`` files. If a recipe
+   requires ``FILES_${PN}-dbg`` to be set manually, the
+   ``NOAUTOPACKAGEDEBUG`` can be defined allowing you to define the
+   content of the debug package. For example: NOAUTOPACKAGEDEBUG = "1"
+   FILES_${PN}-dev = "${includedir}/${QT_DIR_NAME}/Qt/*" FILES_${PN}-dbg
+   = "/usr/src/debug/" FILES_${QT_BASE_NAME}-demos-doc =
+   "${docdir}/${QT_DIR_NAME}/qch/qt.qch"
+OBJCOPY
+   The minimal command and arguments to run ``objcopy``.
+OBJDUMP
+   The minimal command and arguments to run ``objdump``.
+OE_BINCONFIG_EXTRA_MANGLE
+   When inheriting the ```binconfig`` <#ref-classes-binconfig>`__ class,
+   this variable specifies additional arguments passed to the "sed"
+   command. The sed command alters any paths in configuration scripts
+   that have been set up during compilation. Inheriting this class
+   results in all paths in these scripts being changed to point into the
+   ``sysroots/`` directory so that all builds that use the script will
+   use the correct directories for the cross compiling layout.
+   See the ``meta/classes/binconfig.bbclass`` in the `Source
+   Directory <#source-directory>`__ for details on how this class
+   applies these additional sed command arguments. For general
+   information on the ``binconfig`` class, see the
+   "```binconfig.bbclass`` <#ref-classes-binconfig>`__" section.
+OE_IMPORTS
+   An internal variable used to tell the OpenEmbedded build system what
+   Python modules to import for every Python function run by the system.
+   .. note::
+      Do not set this variable. It is for internal use only.
+OE_INIT_ENV_SCRIPT
+   The name of the build environment setup script for the purposes of
+   setting up the environment within the extensible SDK. The default
+   value is "oe-init-build-env".
+   If you use a custom script to set up your build environment, set the
+   ``OE_INIT_ENV_SCRIPT`` variable to its name.
+OE_TERMINAL
+   Controls how the OpenEmbedded build system spawns interactive
+   terminals on the host development system (e.g. using the BitBake
+   command with the ``-c devshell`` command-line option). For more
+   information, see the "`Using a Development
+   Shell <&YOCTO_DOCS_DEV_URL;#platdev-appdev-devshell>`__" section in
+   the Yocto Project Development Tasks Manual.
+   You can use the following values for the ``OE_TERMINAL`` variable:
+   auto gnome xfce rxvt screen konsole none
+OEROOT
+   The directory from which the top-level build environment setup script
+   is sourced. The Yocto Project provides a top-level build environment
+   setup script: ````` <#structure-core-script>`__. When you run this
+   script, the ``OEROOT`` variable resolves to the directory that
+   contains the script.
+   For additional information on how this variable is used, see the
+   initialization script.
+OLDEST_KERNEL
+   Declares the oldest version of the Linux kernel that the produced
+   binaries must support. This variable is passed into the build of the
+   Embedded GNU C Library (``glibc``).
+   The default for this variable comes from the
+   ``meta/conf/bitbake.conf`` configuration file. You can override this
+   default by setting the variable in a custom distribution
+   configuration file.
+OVERRIDES
+   A colon-separated list of overrides that currently apply. Overrides
+   are a BitBake mechanism that allows variables to be selectively
+   overridden at the end of parsing. The set of overrides in
+   ``OVERRIDES`` represents the "state" during building, which includes
+   the current recipe being built, the machine for which it is being
+   built, and so forth.
+   As an example, if the string "an-override" appears as an element in
+   the colon-separated list in ``OVERRIDES``, then the following
+   assignment will override ``FOO`` with the value "overridden" at the
+   end of parsing: FOO_an-override = "overridden" See the "`Conditional
+   Syntax
+   (Overrides) <&YOCTO_DOCS_BB_URL;#conditional-syntax-overrides>`__"
+   section in the BitBake User Manual for more information on the
+   overrides mechanism.
+   The default value of ``OVERRIDES`` includes the values of the
+   ```CLASSOVERRIDE`` <#var-CLASSOVERRIDE>`__,
+   ```MACHINEOVERRIDES`` <#var-MACHINEOVERRIDES>`__, and
+   ```DISTROOVERRIDES`` <#var-DISTROOVERRIDES>`__ variables. Another
+   important override included by default is ``pn-${PN}``. This override
+   allows variables to be set for a single recipe within configuration
+   (``.conf``) files. Here is an example: FOO_pn-myrecipe =
+   "myrecipe-specific value"
+   .. note::
+      An easy way to see what overrides apply is to search for
+      OVERRIDES
+      in the output of the
+      bitbake -e
+      command. See the "
+      Viewing Variable Values
+      " section in the Yocto Project Development Tasks Manual for more
+      information.
+P
+   The recipe name and version. ``P`` is comprised of the following:
+   ${PN}-${PV}
+PACKAGE_ADD_METADATA
+   This variable defines additional metdata to add to packages.
+   You may find you need to inject additional metadata into packages.
+   This variable allows you to do that by setting the injected data as
+   the value. Multiple fields can be added by splitting the content with
+   the literal separator "\n".
+   The suffixes '_IPK', '_DEB', or '_RPM' can be applied to the variable
+   to do package type specific settings. It can also be made package
+   specific by using the package name as a suffix.
+   You can find out more about applying this variable in the "`Adding
+   custom metadata to
+   packages <&YOCTO_DOCS_DEV_URL;#adding-custom-metadata-to-packages>`__"
+   section in the Yocto Project Development Tasks Manual.
+PACKAGE_ARCH
+   The architecture of the resulting package or packages.
+   By default, the value of this variable is set to
+   ```TUNE_PKGARCH`` <#var-TUNE_PKGARCH>`__ when building for the
+   target, ```BUILD_ARCH`` <#var-BUILD_ARCH>`__ when building for the
+   build host, and "${SDK_ARCH}-${SDKPKGSUFFIX}" when building for the
+   SDK.
+   .. note::
+      See
+      SDK_ARCH
+      for more information.
+   However, if your recipe's output packages are built specific to the
+   target machine rather than generally for the architecture of the
+   machine, you should set ``PACKAGE_ARCH`` to the value of
+   ```MACHINE_ARCH`` <#var-MACHINE_ARCH>`__ in the recipe as follows:
+   PACKAGE_ARCH = "${MACHINE_ARCH}"
+PACKAGE_ARCHS
+   Specifies a list of architectures compatible with the target machine.
+   This variable is set automatically and should not normally be
+   hand-edited. Entries are separated using spaces and listed in order
+   of priority. The default value for ``PACKAGE_ARCHS`` is "all any
+   noarch ${PACKAGE_EXTRA_ARCHS} ${MACHINE_ARCH}".
+PACKAGE_BEFORE_PN
+   Enables easily adding packages to ``PACKAGES`` before ``${PN}`` so
+   that those added packages can pick up files that would normally be
+   included in the default package.
+PACKAGE_CLASSES
+   This variable, which is set in the ``local.conf`` configuration file
+   found in the ``conf`` folder of the `Build
+   Directory <#build-directory>`__, specifies the package manager the
+   OpenEmbedded build system uses when packaging data.
+   You can provide one or more of the following arguments for the
+   variable: PACKAGE_CLASSES ?= "package_rpm package_deb package_ipk
+   package_tar"
+   .. note::
+      While it is a legal option, the
+      package_tar
+      class has limited functionality due to no support for package
+      dependencies by that backend. Therefore, it is recommended that
+      you do not use it.
+   The build system uses only the first argument in the list as the
+   package manager when creating your image or SDK. However, packages
+   will be created using any additional packaging classes you specify.
+   For example, if you use the following in your ``local.conf`` file:
+   PACKAGE_CLASSES ?= "package_ipk" The OpenEmbedded build system uses
+   the IPK package manager to create your image or SDK.
+   For information on packaging and build performance effects as a
+   result of the package manager in use, see the
+   "```package.bbclass`` <#ref-classes-package>`__" section.
+PACKAGE_DEBUG_SPLIT_STYLE
+   Determines how to split up the binary and debug information when
+   creating ``*-dbg`` packages to be used with the GNU Project Debugger
+   (GDB).
+   With the ``PACKAGE_DEBUG_SPLIT_STYLE`` variable, you can control
+   where debug information, which can include or exclude source files,
+   is stored:
+   -  ".debug": Debug symbol files are placed next to the binary in a
+      ``.debug`` directory on the target. For example, if a binary is
+      installed into ``/bin``, the corresponding debug symbol files are
+      installed in ``/bin/.debug``. Source files are placed in
+      ``/usr/src/debug``.
+   -  "debug-file-directory": Debug symbol files are placed under
+      ``/usr/lib/debug`` on the target, and separated by the path from
+      where the binary is installed. For example, if a binary is
+      installed in ``/bin``, the corresponding debug symbols are
+      installed in ``/usr/lib/debug/bin``. Source files are placed in
+      ``/usr/src/debug``.
+   -  "debug-without-src": The same behavior as ".debug" previously
+      described with the exception that no source files are installed.
+   -  "debug-with-srcpkg": The same behavior as ".debug" previously
+      described with the exception that all source files are placed in a
+      separate ``*-src`` pkg. This is the default behavior.
+   You can find out more about debugging using GDB by reading the
+   "`Debugging With the GNU Project Debugger (GDB)
+   Remotely <&YOCTO_DOCS_DEV_URL;#platdev-gdb-remotedebug>`__" section
+   in the Yocto Project Development Tasks Manual.
+PACKAGE_EXCLUDE_COMPLEMENTARY
+   Prevents specific packages from being installed when you are
+   installing complementary packages.
+   You might find that you want to prevent installing certain packages
+   when you are installing complementary packages. For example, if you
+   are using ```IMAGE_FEATURES`` <#var-IMAGE_FEATURES>`__ to install
+   ``dev-pkgs``, you might not want to install all packages from a
+   particular multilib. If you find yourself in this situation, you can
+   use the ``PACKAGE_EXCLUDE_COMPLEMENTARY`` variable to specify regular
+   expressions to match the packages you want to exclude.
+PACKAGE_EXCLUDE
+   Lists packages that should not be installed into an image. For
+   example: PACKAGE_EXCLUDE = "package_name package_name package_name
+   ..."
+   You can set this variable globally in your ``local.conf`` file or you
+   can attach it to a specific image recipe by using the recipe name
+   override: PACKAGE_EXCLUDE_pn-target_image = "package_name"
+   If you choose to not install a package using this variable and some
+   other package is dependent on it (i.e. listed in a recipe's
+   ```RDEPENDS`` <#var-RDEPENDS>`__ variable), the OpenEmbedded build
+   system generates a fatal installation error. Because the build system
+   halts the process with a fatal error, you can use the variable with
+   an iterative development process to remove specific components from a
+   system.
+   Support for this variable exists only when using the IPK and RPM
+   packaging backend. Support does not exist for DEB.
+   See the ```NO_RECOMMENDATIONS`` <#var-NO_RECOMMENDATIONS>`__ and the
+   ```BAD_RECOMMENDATIONS`` <#var-BAD_RECOMMENDATIONS>`__ variables for
+   related information.
+PACKAGE_EXTRA_ARCHS
+   Specifies the list of architectures compatible with the device CPU.
+   This variable is useful when you build for several different devices
+   that use miscellaneous processors such as XScale and ARM926-EJS.
+PACKAGE_FEED_ARCHS
+   Optionally specifies the package architectures used as part of the
+   package feed URIs during the build. When used, the
+   ``PACKAGE_FEED_ARCHS`` variable is appended to the final package feed
+   URI, which is constructed using the
+   ```PACKAGE_FEED_URIS`` <#var-PACKAGE_FEED_URIS>`__ and
+   ```PACKAGE_FEED_BASE_PATHS`` <#var-PACKAGE_FEED_BASE_PATHS>`__
+   variables.
+   .. note::
+      You can use the
+      PACKAGE_FEEDS_ARCHS
+      variable to whitelist specific package architectures. If you do
+      not need to whitelist specific architectures, which is a common
+      case, you can omit this variable. Omitting the variable results in
+      all available architectures for the current machine being included
+      into remote package feeds.
+   Consider the following example where the ``PACKAGE_FEED_URIS``,
+   ``PACKAGE_FEED_BASE_PATHS``, and ``PACKAGE_FEED_ARCHS`` variables are
+   defined in your ``local.conf`` file: PACKAGE_FEED_URIS =
+   "https://example.com/packagerepos/release \\
+   https://example.com/packagerepos/updates" PACKAGE_FEED_BASE_PATHS =
+   "rpm rpm-dev" PACKAGE_FEED_ARCHS = "all core2-64" Given these
+   settings, the resulting package feeds are as follows:
+   https://example.com/packagerepos/release/rpm/all
+   https://example.com/packagerepos/release/rpm/core2-64
+   https://example.com/packagerepos/release/rpm-dev/all
+   https://example.com/packagerepos/release/rpm-dev/core2-64
+   https://example.com/packagerepos/updates/rpm/all
+   https://example.com/packagerepos/updates/rpm/core2-64
+   https://example.com/packagerepos/updates/rpm-dev/all
+   https://example.com/packagerepos/updates/rpm-dev/core2-64
+PACKAGE_FEED_BASE_PATHS
+   Specifies the base path used when constructing package feed URIs. The
+   ``PACKAGE_FEED_BASE_PATHS`` variable makes up the middle portion of a
+   package feed URI used by the OpenEmbedded build system. The base path
+   lies between the ```PACKAGE_FEED_URIS`` <#var-PACKAGE_FEED_URIS>`__
+   and ```PACKAGE_FEED_ARCHS`` <#var-PACKAGE_FEED_ARCHS>`__ variables.
+   Consider the following example where the ``PACKAGE_FEED_URIS``,
+   ``PACKAGE_FEED_BASE_PATHS``, and ``PACKAGE_FEED_ARCHS`` variables are
+   defined in your ``local.conf`` file: PACKAGE_FEED_URIS =
+   "https://example.com/packagerepos/release \\
+   https://example.com/packagerepos/updates" PACKAGE_FEED_BASE_PATHS =
+   "rpm rpm-dev" PACKAGE_FEED_ARCHS = "all core2-64" Given these
+   settings, the resulting package feeds are as follows:
+   https://example.com/packagerepos/release/rpm/all
+   https://example.com/packagerepos/release/rpm/core2-64
+   https://example.com/packagerepos/release/rpm-dev/all
+   https://example.com/packagerepos/release/rpm-dev/core2-64
+   https://example.com/packagerepos/updates/rpm/all
+   https://example.com/packagerepos/updates/rpm/core2-64
+   https://example.com/packagerepos/updates/rpm-dev/all
+   https://example.com/packagerepos/updates/rpm-dev/core2-64
+PACKAGE_FEED_URIS
+   Specifies the front portion of the package feed URI used by the
+   OpenEmbedded build system. Each final package feed URI is comprised
+   of ``PACKAGE_FEED_URIS``,
+   ```PACKAGE_FEED_BASE_PATHS`` <#var-PACKAGE_FEED_BASE_PATHS>`__, and
+   ```PACKAGE_FEED_ARCHS`` <#var-PACKAGE_FEED_ARCHS>`__ variables.
+   Consider the following example where the ``PACKAGE_FEED_URIS``,
+   ``PACKAGE_FEED_BASE_PATHS``, and ``PACKAGE_FEED_ARCHS`` variables are
+   defined in your ``local.conf`` file: PACKAGE_FEED_URIS =
+   "https://example.com/packagerepos/release \\
+   https://example.com/packagerepos/updates" PACKAGE_FEED_BASE_PATHS =
+   "rpm rpm-dev" PACKAGE_FEED_ARCHS = "all core2-64" Given these
+   settings, the resulting package feeds are as follows:
+   https://example.com/packagerepos/release/rpm/all
+   https://example.com/packagerepos/release/rpm/core2-64
+   https://example.com/packagerepos/release/rpm-dev/all
+   https://example.com/packagerepos/release/rpm-dev/core2-64
+   https://example.com/packagerepos/updates/rpm/all
+   https://example.com/packagerepos/updates/rpm/core2-64
+   https://example.com/packagerepos/updates/rpm-dev/all
+   https://example.com/packagerepos/updates/rpm-dev/core2-64
+PACKAGE_INSTALL
+   The final list of packages passed to the package manager for
+   installation into the image.
+   Because the package manager controls actual installation of all
+   packages, the list of packages passed using ``PACKAGE_INSTALL`` is
+   not the final list of packages that are actually installed. This
+   variable is internal to the image construction code. Consequently, in
+   general, you should use the
+   ```IMAGE_INSTALL`` <#var-IMAGE_INSTALL>`__ variable to specify
+   packages for installation. The exception to this is when working with
+   the
+   ```core-image-minimal-initramfs`` <#images-core-image-minimal-initramfs>`__
+   image. When working with an initial RAM filesystem (initramfs) image,
+   use the ``PACKAGE_INSTALL`` variable. For information on creating an
+   initramfs, see the "`Building an Initial RAM Filesystem (initramfs)
+   Image <&YOCTO_DOCS_DEV_URL;#building-an-initramfs-image>`__" section
+   in the Yocto Project Development Tasks Manual.
+PACKAGE_INSTALL_ATTEMPTONLY
+   Specifies a list of packages the OpenEmbedded build system attempts
+   to install when creating an image. If a listed package fails to
+   install, the build system does not generate an error. This variable
+   is generally not user-defined.
+PACKAGE_PREPROCESS_FUNCS
+   Specifies a list of functions run to pre-process the
+   ```PKGD`` <#var-PKGD>`__ directory prior to splitting the files out
+   to individual packages.
+PACKAGE_WRITE_DEPS
+   Specifies a list of dependencies for post-installation and
+   pre-installation scripts on native/cross tools. If your
+   post-installation or pre-installation script can execute at rootfs
+   creation time rather than on the target but depends on a native tool
+   in order to execute, you need to list the tools in
+   ``PACKAGE_WRITE_DEPS``.
+   For information on running post-installation scripts, see the
+   "`Post-Installation
+   Scripts <&YOCTO_DOCS_DEV_URL;#new-recipe-post-installation-scripts>`__"
+   section in the Yocto Project Development Tasks Manual.
+PACKAGECONFIG
+   This variable provides a means of enabling or disabling features of a
+   recipe on a per-recipe basis. ``PACKAGECONFIG`` blocks are defined in
+   recipes when you specify features and then arguments that define
+   feature behaviors. Here is the basic block structure (broken over
+   multiple lines for readability): PACKAGECONFIG ??= "f1 f2 f3 ..."
+   PACKAGECONFIG[f1] = "\\ --with-f1, \\ --without-f1, \\
+   build-deps-for-f1, \\ runtime-deps-for-f1, \\
+   runtime-recommends-for-f1, \\ packageconfig-conflicts-for-f1 \\ "
+   PACKAGECONFIG[f2] = "\\ ... and so on and so on ...
+   The ``PACKAGECONFIG`` variable itself specifies a space-separated
+   list of the features to enable. Following the features, you can
+   determine the behavior of each feature by providing up to six
+   order-dependent arguments, which are separated by commas. You can
+   omit any argument you like but must retain the separating commas. The
+   order is important and specifies the following:
+   1. Extra arguments that should be added to the configure script
+      argument list (```EXTRA_OECONF`` <#var-EXTRA_OECONF>`__ or
+      ```PACKAGECONFIG_CONFARGS`` <#var-PACKAGECONFIG_CONFARGS>`__) if
+      the feature is enabled.
+   2. Extra arguments that should be added to ``EXTRA_OECONF`` or
+      ``PACKAGECONFIG_CONFARGS`` if the feature is disabled.
+   3. Additional build dependencies (```DEPENDS`` <#var-DEPENDS>`__)
+      that should be added if the feature is enabled.
+   4. Additional runtime dependencies (```RDEPENDS`` <#var-RDEPENDS>`__)
+      that should be added if the feature is enabled.
+   5. Additional runtime recommendations
+      (```RRECOMMENDS`` <#var-RRECOMMENDS>`__) that should be added if
+      the feature is enabled.
+   6. Any conflicting (that is, mutually exclusive) ``PACKAGECONFIG``
+      settings for this feature.
+   Consider the following ``PACKAGECONFIG`` block taken from the
+   ``librsvg`` recipe. In this example the feature is ``gtk``, which has
+   three arguments that determine the feature's behavior.
+   PACKAGECONFIG[gtk] = "--with-gtk3,--without-gtk3,gtk+3" The
+   ``--with-gtk3`` and ``gtk+3`` arguments apply only if the feature is
+   enabled. In this case, ``--with-gtk3`` is added to the configure
+   script argument list and ``gtk+3`` is added to ``DEPENDS``. On the
+   other hand, if the feature is disabled say through a ``.bbappend``
+   file in another layer, then the second argument ``--without-gtk3`` is
+   added to the configure script instead.
+   The basic ``PACKAGECONFIG`` structure previously described holds true
+   regardless of whether you are creating a block or changing a block.
+   When creating a block, use the structure inside your recipe.
+   If you want to change an existing ``PACKAGECONFIG`` block, you can do
+   so one of two ways:
+   -  *Append file:* Create an append file named
+      recipename\ ``.bbappend`` in your layer and override the value of
+      ``PACKAGECONFIG``. You can either completely override the
+      variable: PACKAGECONFIG = "f4 f5" Or, you can just append the
+      variable: PACKAGECONFIG_append = " f4"
+   -  *Configuration file:* This method is identical to changing the
+      block through an append file except you edit your ``local.conf``
+      or ``mydistro.conf`` file. As with append files previously
+      described, you can either completely override the variable:
+      PACKAGECONFIG_pn-recipename = "f4 f5" Or, you can just amend the
+      variable: PACKAGECONFIG_append_pn-recipename = " f4"
+PACKAGECONFIG_CONFARGS
+   A space-separated list of configuration options generated from the
+   ```PACKAGECONFIG`` <#var-PACKAGECONFIG>`__ setting.
+   Classes such as ```autotools`` <#ref-classes-autotools>`__ and
+   ```cmake`` <#ref-classes-cmake>`__ use ``PACKAGECONFIG_CONFARGS`` to
+   pass ``PACKAGECONFIG`` options to ``configure`` and ``cmake``,
+   respectively. If you are using ``PACKAGECONFIG`` but not a class that
+   handles the ``do_configure`` task, then you need to use
+   ``PACKAGECONFIG_CONFARGS`` appropriately.
+PACKAGEGROUP_DISABLE_COMPLEMENTARY
+   For recipes inheriting the
+   ```packagegroup`` <#ref-classes-packagegroup>`__ class, setting
+   ``PACKAGEGROUP_DISABLE_COMPLEMENTARY`` to "1" specifies that the
+   normal complementary packages (i.e. ``-dev``, ``-dbg``, and so forth)
+   should not be automatically created by the ``packagegroup`` recipe,
+   which is the default behavior.
+PACKAGES
+   The list of packages the recipe creates. The default value is the
+   following: ${PN}-dbg ${PN}-staticdev ${PN}-dev ${PN}-doc ${PN}-locale
+   ${PACKAGE_BEFORE_PN} ${PN}
+   During packaging, the ```do_package`` <#ref-tasks-package>`__ task
+   goes through ``PACKAGES`` and uses the ```FILES`` <#var-FILES>`__
+   variable corresponding to each package to assign files to the
+   package. If a file matches the ``FILES`` variable for more than one
+   package in ``PACKAGES``, it will be assigned to the earliest
+   (leftmost) package.
+   Packages in the variable's list that are empty (i.e. where none of
+   the patterns in ``FILES_``\ pkg match any files installed by the
+   ```do_install`` <#ref-tasks-install>`__ task) are not generated,
+   unless generation is forced through the
+   ```ALLOW_EMPTY`` <#var-ALLOW_EMPTY>`__ variable.
+PACKAGES_DYNAMIC
+   A promise that your recipe satisfies runtime dependencies for
+   optional modules that are found in other recipes.
+   ``PACKAGES_DYNAMIC`` does not actually satisfy the dependencies, it
+   only states that they should be satisfied. For example, if a hard,
+   runtime dependency (```RDEPENDS`` <#var-RDEPENDS>`__) of another
+   package is satisfied at build time through the ``PACKAGES_DYNAMIC``
+   variable, but a package with the module name is never actually
+   produced, then the other package will be broken. Thus, if you attempt
+   to include that package in an image, you will get a dependency
+   failure from the packaging system during the
+   ```do_rootfs`` <#ref-tasks-rootfs>`__ task.
+   Typically, if there is a chance that such a situation can occur and
+   the package that is not created is valid without the dependency being
+   satisfied, then you should use ```RRECOMMENDS`` <#var-RRECOMMENDS>`__
+   (a soft runtime dependency) instead of ``RDEPENDS``.
+   For an example of how to use the ``PACKAGES_DYNAMIC`` variable when
+   you are splitting packages, see the "`Handling Optional Module
+   Packaging <&YOCTO_DOCS_DEV_URL;#handling-optional-module-packaging>`__"
+   section in the Yocto Project Development Tasks Manual.
+PACKAGESPLITFUNCS
+   Specifies a list of functions run to perform additional splitting of
+   files into individual packages. Recipes can either prepend to this
+   variable or prepend to the ``populate_packages`` function in order to
+   perform additional package splitting. In either case, the function
+   should set ```PACKAGES`` <#var-PACKAGES>`__,
+   ```FILES`` <#var-FILES>`__, ```RDEPENDS`` <#var-RDEPENDS>`__ and
+   other packaging variables appropriately in order to perform the
+   desired splitting.
+PARALLEL_MAKE
+   Extra options passed to the ``make`` command during the
+   ```do_compile`` <#ref-tasks-compile>`__ task in order to specify
+   parallel compilation on the local build host. This variable is
+   usually in the form "-j x", where x represents the maximum number of
+   parallel threads ``make`` can run.
+   .. note::
+      In order for
+      PARALLEL_MAKE
+      to be effective,
+      make
+      must be called with
+      ${
+      EXTRA_OEMAKE
+      }
+      . An easy way to ensure this is to use the
+      oe_runmake
+      function.
+   By default, the OpenEmbedded build system automatically sets this
+   variable to be equal to the number of cores the build system uses.
+   .. note::
+      If the software being built experiences dependency issues during
+      the
+      do_compile
+      task that result in race conditions, you can clear the
+      PARALLEL_MAKE
+      variable within the recipe as a workaround. For information on
+      addressing race conditions, see the "
+      Debugging Parallel Make Races
+      " section in the Yocto Project Development Tasks Manual.
+   For single socket systems (i.e. one CPU), you should not have to
+   override this variable to gain optimal parallelism during builds.
+   However, if you have very large systems that employ multiple physical
+   CPUs, you might want to make sure the ``PARALLEL_MAKE`` variable is
+   not set higher than "-j 20".
+   For more information on speeding up builds, see the "`Speeding Up a
+   Build <&YOCTO_DOCS_DEV_URL;#speeding-up-a-build>`__" section in the
+   Yocto Project Development Tasks Manual.
+PARALLEL_MAKEINST
+   Extra options passed to the ``make install`` command during the
+   ```do_install`` <#ref-tasks-install>`__ task in order to specify
+   parallel installation. This variable defaults to the value of
+   ```PARALLEL_MAKE`` <#var-PARALLEL_MAKE>`__.
+   .. note::
+      In order for ``PARALLEL_MAKEINST`` to be effective, ``make`` must
+      be called with
+      ``${``\ ```EXTRA_OEMAKE`` <#var-EXTRA_OEMAKE>`__\ ``}``. An easy
+      way to ensure this is to use the ``oe_runmake`` function.
+      If the software being built experiences dependency issues during
+      the ``do_install`` task that result in race conditions, you can
+      clear the ``PARALLEL_MAKEINST`` variable within the recipe as a
+      workaround. For information on addressing race conditions, see the
+      "`Debugging Parallel Make
+      Races <&YOCTO_DOCS_DEV_URL;#debugging-parallel-make-races>`__"
+      section in the Yocto Project Development Tasks Manual.
+PATCHRESOLVE
+   Determines the action to take when a patch fails. You can set this
+   variable to one of two values: "noop" and "user".
+   The default value of "noop" causes the build to simply fail when the
+   OpenEmbedded build system cannot successfully apply a patch. Setting
+   the value to "user" causes the build system to launch a shell and
+   places you in the right location so that you can manually resolve the
+   conflicts.
+   Set this variable in your ``local.conf`` file.
+PATCHTOOL
+   Specifies the utility used to apply patches for a recipe during the
+   ```do_patch`` <#ref-tasks-patch>`__ task. You can specify one of
+   three utilities: "patch", "quilt", or "git". The default utility used
+   is "quilt" except for the quilt-native recipe itself. Because the
+   quilt tool is not available at the time quilt-native is being
+   patched, it uses "patch".
+   If you wish to use an alternative patching tool, set the variable in
+   the recipe using one of the following: PATCHTOOL = "patch" PATCHTOOL
+   = "quilt" PATCHTOOL = "git"
+PE
+   The epoch of the recipe. By default, this variable is unset. The
+   variable is used to make upgrades possible when the versioning scheme
+   changes in some backwards incompatible way.
+   ``PE`` is the default value of the ```PKGE`` <#var-PKGE>`__ variable.
+PF
+   Specifies the recipe or package name and includes all version and
+   revision numbers (i.e. ``glibc-2.13-r20+svnr15508/`` and
+   ``bash-4.2-r1/``). This variable is comprised of the following:
+   ${`PN <#var-PN>`__}-${`EXTENDPE <#var-EXTENDPE>`__}${`PV <#var-PV>`__}-${`PR <#var-PR>`__}
+PIXBUF_PACKAGES
+   When inheriting the ```pixbufcache`` <#ref-classes-pixbufcache>`__
+   class, this variable identifies packages that contain the pixbuf
+   loaders used with ``gdk-pixbuf``. By default, the ``pixbufcache``
+   class assumes that the loaders are in the recipe's main package (i.e.
+   ``${``\ ```PN`` <#var-PN>`__\ ``}``). Use this variable if the
+   loaders you need are in a package other than that main package.
+PKG
+   The name of the resulting package created by the OpenEmbedded build
+   system.
+   .. note::
+      When using the
+      PKG
+      variable, you must use a package name override.
+   For example, when the ```debian`` <#ref-classes-debian>`__ class
+   renames the output package, it does so by setting
+   ``PKG_packagename``.
+PKG_CONFIG_PATH
+   The path to ``pkg-config`` files for the current build context.
+   ``pkg-config`` reads this variable from the environment.
+PKGD
+   Points to the destination directory for files to be packaged before
+   they are split into individual packages. This directory defaults to
+   the following: ${WORKDIR}/package
+   Do not change this default.
+PKGDATA_DIR
+   Points to a shared, global-state directory that holds data generated
+   during the packaging process. During the packaging process, the
+   ```do_packagedata`` <#ref-tasks-packagedata>`__ task packages data
+   for each recipe and installs it into this temporary, shared area.
+   This directory defaults to the following, which you should not
+   change: ${STAGING_DIR_HOST}/pkgdata For examples of how this data is
+   used, see the "`Automatically Added Runtime
+   Dependencies <&YOCTO_DOCS_OM_URL;#automatically-added-runtime-dependencies>`__"
+   section in the Yocto Project Overview and Concepts Manual and the
+   "`Viewing Package Information with
+   ``oe-pkgdata-util`` <&YOCTO_DOCS_DEV_URL;#viewing-package-information-with-oe-pkgdata-util>`__"
+   section in the Yocto Project Development Tasks Manual. For more
+   information on the shared, global-state directory, see
+   ```STAGING_DIR_HOST`` <#var-STAGING_DIR_HOST>`__.
+PKGDEST
+   Points to the parent directory for files to be packaged after they
+   have been split into individual packages. This directory defaults to
+   the following: ${WORKDIR}/packages-split
+   Under this directory, the build system creates directories for each
+   package specified in ```PACKAGES`` <#var-PACKAGES>`__. Do not change
+   this default.
+PKGDESTWORK
+   Points to a temporary work area where the
+   ```do_package`` <#ref-tasks-package>`__ task saves package metadata.
+   The ``PKGDESTWORK`` location defaults to the following:
+   ${WORKDIR}/pkgdata Do not change this default.
+   The ```do_packagedata`` <#ref-tasks-packagedata>`__ task copies the
+   package metadata from ``PKGDESTWORK`` to
+   ```PKGDATA_DIR`` <#var-PKGDATA_DIR>`__ to make it available globally.
+PKGE
+   The epoch of the package(s) built by the recipe. By default, ``PKGE``
+   is set to ```PE`` <#var-PE>`__.
+PKGR
+   The revision of the package(s) built by the recipe. By default,
+   ``PKGR`` is set to ```PR`` <#var-PR>`__.
+PKGV
+   The version of the package(s) built by the recipe. By default,
+   ``PKGV`` is set to ```PV`` <#var-PV>`__.
+PN
+   This variable can have two separate functions depending on the
+   context: a recipe name or a resulting package name.
+   ``PN`` refers to a recipe name in the context of a file used by the
+   OpenEmbedded build system as input to create a package. The name is
+   normally extracted from the recipe file name. For example, if the
+   recipe is named ``expat_2.0.1.bb``, then the default value of ``PN``
+   will be "expat".
+   The variable refers to a package name in the context of a file
+   created or produced by the OpenEmbedded build system.
+   If applicable, the ``PN`` variable also contains any special suffix
+   or prefix. For example, using ``bash`` to build packages for the
+   native machine, ``PN`` is ``bash-native``. Using ``bash`` to build
+   packages for the target and for Multilib, ``PN`` would be ``bash``
+   and ``lib64-bash``, respectively.
+PNBLACKLIST
+   Lists recipes you do not want the OpenEmbedded build system to build.
+   This variable works in conjunction with the
+   ```blacklist`` <#ref-classes-blacklist>`__ class, which is inherited
+   globally.
+   To prevent a recipe from being built, use the ``PNBLACKLIST``
+   variable in your ``local.conf`` file. Here is an example that
+   prevents ``myrecipe`` from being built: PNBLACKLIST[myrecipe] = "Not
+   supported by our organization."
+POPULATE_SDK_POST_HOST_COMMAND
+   Specifies a list of functions to call once the OpenEmbedded build
+   system has created the host part of the SDK. You can specify
+   functions separated by semicolons: POPULATE_SDK_POST_HOST_COMMAND +=
+   "function; ... "
+   If you need to pass the SDK path to a command within a function, you
+   can use ``${SDK_DIR}``, which points to the parent directory used by
+   the OpenEmbedded build system when creating SDK output. See the
+   ```SDK_DIR`` <#var-SDK_DIR>`__ variable for more information.
+POPULATE_SDK_POST_TARGET_COMMAND
+   Specifies a list of functions to call once the OpenEmbedded build
+   system has created the target part of the SDK. You can specify
+   functions separated by semicolons: POPULATE_SDK_POST_TARGET_COMMAND
+   += "function; ... "
+   If you need to pass the SDK path to a command within a function, you
+   can use ``${SDK_DIR}``, which points to the parent directory used by
+   the OpenEmbedded build system when creating SDK output. See the
+   ```SDK_DIR`` <#var-SDK_DIR>`__ variable for more information.
+PR
+   The revision of the recipe. The default value for this variable is
+   "r0". Subsequent revisions of the recipe conventionally have the
+   values "r1", "r2", and so forth. When ```PV`` <#var-PV>`__ increases,
+   ``PR`` is conventionally reset to "r0".
+   .. note::
+      The OpenEmbedded build system does not need the aid of
+      PR
+      to know when to rebuild a recipe. The build system uses the task
+      input checksums
+      along with the
+      stamp
+      and
+      shared state cache
+      mechanisms.
+   The ``PR`` variable primarily becomes significant when a package
+   manager dynamically installs packages on an already built image. In
+   this case, ``PR``, which is the default value of
+   ```PKGR`` <#var-PKGR>`__, helps the package manager distinguish which
+   package is the most recent one in cases where many packages have the
+   same ``PV`` (i.e. ``PKGV``). A component having many packages with
+   the same ``PV`` usually means that the packages all install the same
+   upstream version, but with later (``PR``) version packages including
+   packaging fixes.
+   .. note::
+      PR
+      does not need to be increased for changes that do not change the
+      package contents or metadata.
+   Because manually managing ``PR`` can be cumbersome and error-prone,
+   an automated solution exists. See the "`Working With a PR
+   Service <&YOCTO_DOCS_DEV_URL;#working-with-a-pr-service>`__" section
+   in the Yocto Project Development Tasks Manual for more information.
+PREFERRED_PROVIDER
+   If multiple recipes provide the same item, this variable determines
+   which recipe is preferred and thus provides the item (i.e. the
+   preferred provider). You should always suffix this variable with the
+   name of the provided item. And, you should define the variable using
+   the preferred recipe's name (```PN`` <#var-PN>`__). Here is a common
+   example: PREFERRED_PROVIDER_virtual/kernel ?= "linux-yocto" In the
+   previous example, multiple recipes are providing "virtual/kernel".
+   The ``PREFERRED_PROVIDER`` variable is set with the name (``PN``) of
+   the recipe you prefer to provide "virtual/kernel".
+   Following are more examples: PREFERRED_PROVIDER_virtual/xserver =
+   "xserver-xf86" PREFERRED_PROVIDER_virtual/libgl ?= "mesa" For more
+   information, see the "`Using Virtual
+   Providers <&YOCTO_DOCS_DEV_URL;#metadata-virtual-providers>`__"
+   section in the Yocto Project Development Tasks Manual.
+   .. note::
+      If you use a
+      virtual/\*
+      item with
+      PREFERRED_PROVIDER
+      , then any recipe that
+      PROVIDES
+      that item but is not selected (defined) by
+      PREFERRED_PROVIDER
+      is prevented from building, which is usually desirable since this
+      mechanism is designed to select between mutually exclusive
+      alternative providers.
+PREFERRED_VERSION
+   If multiple versions of recipes exist, this variable determines which
+   version is given preference. You must always suffix the variable with
+   the ```PN`` <#var-PN>`__ you want to select, and you should set the
+   ```PV`` <#var-PV>`__ accordingly for precedence.
+   The ``PREFERRED_VERSION`` variable supports limited wildcard use
+   through the "``%``" character. You can use the character to match any
+   number of characters, which can be useful when specifying versions
+   that contain long revision numbers that potentially change. Here are
+   two examples: PREFERRED_VERSION_python = "3.4.0"
+   PREFERRED_VERSION_linux-yocto = "5.0%"
+   .. note::
+      The use of the "
+      %
+      " character is limited in that it only works at the end of the
+      string. You cannot use the wildcard character in any other
+      location of the string.
+   The specified version is matched against ```PV`` <#var-PV>`__, which
+   does not necessarily match the version part of the recipe's filename.
+   For example, consider two recipes ``foo_1.2.bb`` and ``foo_git.bb``
+   where ``foo_git.bb`` contains the following assignment: PV =
+   "1.1+git${SRCPV}" In this case, the correct way to select
+   ``foo_git.bb`` is by using an assignment such as the following:
+   PREFERRED_VERSION_foo = "1.1+git%" Compare that previous example
+   against the following incorrect example, which does not work:
+   PREFERRED_VERSION_foo = "git"
+   Sometimes the ``PREFERRED_VERSION`` variable can be set by
+   configuration files in a way that is hard to change. You can use
+   ```OVERRIDES`` <#var-OVERRIDES>`__ to set a machine-specific
+   override. Here is an example: PREFERRED_VERSION_linux-yocto_qemux86 =
+   "5.0%" Although not recommended, worst case, you can also use the
+   "forcevariable" override, which is the strongest override possible.
+   Here is an example: PREFERRED_VERSION_linux-yocto_forcevariable =
+   "5.0%"
+   .. note::
+      The
+      \_forcevariable
+      override is not handled specially. This override only works
+      because the default value of
+      OVERRIDES
+      includes "forcevariable".
+PREMIRRORS
+   Specifies additional paths from which the OpenEmbedded build system
+   gets source code. When the build system searches for source code, it
+   first tries the local download directory. If that location fails, the
+   build system tries locations defined by ``PREMIRRORS``, the upstream
+   source, and then locations specified by
+   ```MIRRORS`` <#var-MIRRORS>`__ in that order.
+   Assuming your distribution (```DISTRO`` <#var-DISTRO>`__) is "poky",
+   the default value for ``PREMIRRORS`` is defined in the
+   ``conf/distro/poky.conf`` file in the ``meta-poky`` Git repository.
+   Typically, you could add a specific server for the build system to
+   attempt before any others by adding something like the following to
+   the ``local.conf`` configuration file in the `Build
+   Directory <#build-directory>`__: PREMIRRORS_prepend = "\\
+   git://.*/.\* http://www.yoctoproject.org/sources/ \\n \\ ftp://.*/.\*
+   http://www.yoctoproject.org/sources/ \\n \\ http://.*/.\*
+   http://www.yoctoproject.org/sources/ \\n \\ https://.*/.\*
+   http://www.yoctoproject.org/sources/ \\n" These changes cause the
+   build system to intercept Git, FTP, HTTP, and HTTPS requests and
+   direct them to the ``http://`` sources mirror. You can use
+   ``file://`` URLs to point to local directories or network shares as
+   well.
+PRIORITY
+   Indicates the importance of a package.
+   ``PRIORITY`` is considered to be part of the distribution policy
+   because the importance of any given recipe depends on the purpose for
+   which the distribution is being produced. Thus, ``PRIORITY`` is not
+   normally set within recipes.
+   You can set ``PRIORITY`` to "required", "standard", "extra", and
+   "optional", which is the default.
+PRIVATE_LIBS
+   Specifies libraries installed within a recipe that should be ignored
+   by the OpenEmbedded build system's shared library resolver. This
+   variable is typically used when software being built by a recipe has
+   its own private versions of a library normally provided by another
+   recipe. In this case, you would not want the package containing the
+   private libraries to be set as a dependency on other unrelated
+   packages that should instead depend on the package providing the
+   standard version of the library.
+   Libraries specified in this variable should be specified by their
+   file name. For example, from the Firefox recipe in meta-browser:
+   PRIVATE_LIBS = "libmozjs.so \\ libxpcom.so \\ libnspr4.so \\
+   libxul.so \\ libmozalloc.so \\ libplc4.so \\ libplds4.so"
+   For more information, see the "`Automatically Added Runtime
+   Dependencies <&YOCTO_DOCS_OM_URL;#automatically-added-runtime-dependencies>`__"
+   section in the Yocto Project Overview and Concepts Manual.
+PROVIDES
+   A list of aliases by which a particular recipe can be known. By
+   default, a recipe's own ``PN`` is implicitly already in its
+   ``PROVIDES`` list and therefore does not need to mention that it
+   provides itself. If a recipe uses ``PROVIDES``, the additional
+   aliases are synonyms for the recipe and can be useful for satisfying
+   dependencies of other recipes during the build as specified by
+   ``DEPENDS``.
+   Consider the following example ``PROVIDES`` statement from the recipe
+   file ``eudev_3.2.9.bb``: PROVIDES = "udev" The ``PROVIDES`` statement
+   results in the "eudev" recipe also being available as simply "udev".
+   .. note::
+      Given that a recipe's own recipe name is already implicitly in its
+      own
+      PROVIDES
+      list, it is unnecessary to add aliases with the "+=" operator;
+      using a simple assignment will be sufficient. In other words,
+      while you could write:
+      ::
+              PROVIDES += "udev"
+                                 
+      in the above, the "+=" is overkill and unnecessary.
+   In addition to providing recipes under alternate names, the
+   ``PROVIDES`` mechanism is also used to implement virtual targets. A
+   virtual target is a name that corresponds to some particular
+   functionality (e.g. a Linux kernel). Recipes that provide the
+   functionality in question list the virtual target in ``PROVIDES``.
+   Recipes that depend on the functionality in question can include the
+   virtual target in ``DEPENDS`` to leave the choice of provider open.
+   Conventionally, virtual targets have names on the form
+   "virtual/function" (e.g. "virtual/kernel"). The slash is simply part
+   of the name and has no syntactical significance.
+   The ```PREFERRED_PROVIDER`` <#var-PREFERRED_PROVIDER>`__ variable is
+   used to select which particular recipe provides a virtual target.
+   .. note::
+      A corresponding mechanism for virtual runtime dependencies
+      (packages) exists. However, the mechanism does not depend on any
+      special functionality beyond ordinary variable assignments. For
+      example, ``VIRTUAL-RUNTIME_dev_manager`` refers to the package of
+      the component that manages the ``/dev`` directory.
+      Setting the "preferred provider" for runtime dependencies is as
+      simple as using the following assignment in a configuration file:
+      ::
+              VIRTUAL-RUNTIME_dev_manager = "udev"
+                                 
+PRSERV_HOST
+   The network based ```PR`` <#var-PR>`__ service host and port.
+   The ``conf/local.conf.sample.extended`` configuration file in the
+   `Source Directory <#source-directory>`__ shows how the
+   ``PRSERV_HOST`` variable is set: PRSERV_HOST = "localhost:0" You must
+   set the variable if you want to automatically start a local `PR
+   service <&YOCTO_DOCS_DEV_URL;#working-with-a-pr-service>`__. You can
+   set ``PRSERV_HOST`` to other values to use a remote PR service.
+PTEST_ENABLED
+   Specifies whether or not `Package
+   Test <&YOCTO_DOCS_DEV_URL;#testing-packages-with-ptest>`__ (ptest)
+   functionality is enabled when building a recipe. You should not set
+   this variable directly. Enabling and disabling building Package Tests
+   at build time should be done by adding "ptest" to (or removing it
+   from) ```DISTRO_FEATURES`` <#var-DISTRO_FEATURES>`__.
+PV
+   The version of the recipe. The version is normally extracted from the
+   recipe filename. For example, if the recipe is named
+   ``expat_2.0.1.bb``, then the default value of ``PV`` will be "2.0.1".
+   ``PV`` is generally not overridden within a recipe unless it is
+   building an unstable (i.e. development) version from a source code
+   repository (e.g. Git or Subversion).
+   ``PV`` is the default value of the ```PKGV`` <#var-PKGV>`__ variable.
+PYTHON_ABI
+   When used by recipes that inherit the
+   ```distutils3`` <#ref-classes-distutils3>`__,
+   ```setuptools3`` <#ref-classes-setuptools3>`__,
+   ```distutils`` <#ref-classes-distutils>`__, or
+   ```setuptools`` <#ref-classes-setuptools>`__ classes, denotes the
+   Application Binary Interface (ABI) currently in use for Python. By
+   default, the ABI is "m". You do not have to set this variable as the
+   OpenEmbedded build system sets it for you.
+   The OpenEmbedded build system uses the ABI to construct directory
+   names used when installing the Python headers and libraries in
+   sysroot (e.g. ``.../python3.3m/...``).
+   Recipes that inherit the ``distutils`` class during cross-builds also
+   use this variable to locate the headers and libraries of the
+   appropriate Python that the extension is targeting.
+PYTHON_PN
+   When used by recipes that inherit the
+   ```distutils3`` <#ref-classes-distutils3>`__,
+   ```setuptools3`` <#ref-classes-setuptools3>`__,
+   ```distutils`` <#ref-classes-distutils>`__, or
+   ```setuptools`` <#ref-classes-setuptools>`__ classes, specifies the
+   major Python version being built. For Python 3.x, ``PYTHON_PN`` would
+   be "python3". You do not have to set this variable as the
+   OpenEmbedded build system automatically sets it for you.
+   The variable allows recipes to use common infrastructure such as the
+   following: DEPENDS += "${PYTHON_PN}-native" In the previous example,
+   the version of the dependency is ``PYTHON_PN``.
+RANLIB
+   The minimal command and arguments to run ``ranlib``.
+RCONFLICTS
+   The list of packages that conflict with packages. Note that packages
+   will not be installed if conflicting packages are not first removed.
+   Like all package-controlling variables, you must always use them in
+   conjunction with a package name override. Here is an example:
+   RCONFLICTS_${PN} = "another_conflicting_package_name"
+   BitBake, which the OpenEmbedded build system uses, supports
+   specifying versioned dependencies. Although the syntax varies
+   depending on the packaging format, BitBake hides these differences
+   from you. Here is the general syntax to specify versions with the
+   ``RCONFLICTS`` variable: RCONFLICTS_${PN} = "package (operator
+   version)" For ``operator``, you can specify the following: = < > <=
+   >= For example, the following sets up a dependency on version 1.2 or
+   greater of the package ``foo``: RCONFLICTS_${PN} = "foo (>= 1.2)"
+RDEPENDS
+   Lists runtime dependencies of a package. These dependencies are other
+   packages that must be installed in order for the package to function
+   correctly. As an example, the following assignment declares that the
+   package ``foo`` needs the packages ``bar`` and ``baz`` to be
+   installed: RDEPENDS_foo = "bar baz" The most common types of package
+   runtime dependencies are automatically detected and added. Therefore,
+   most recipes do not need to set ``RDEPENDS``. For more information,
+   see the "`Automatically Added Runtime
+   Dependencies <&YOCTO_DOCS_OM_URL;#automatically-added-runtime-dependencies>`__"
+   section in the Yocto Project Overview and Concepts Manual.
+   The practical effect of the above ``RDEPENDS`` assignment is that
+   ``bar`` and ``baz`` will be declared as dependencies inside the
+   package ``foo`` when it is written out by one of the
+   ```do_package_write_*`` <#ref-tasks-package_write_deb>`__ tasks.
+   Exactly how this is done depends on which package format is used,
+   which is determined by
+   ```PACKAGE_CLASSES`` <#var-PACKAGE_CLASSES>`__. When the
+   corresponding package manager installs the package, it will know to
+   also install the packages on which it depends.
+   To ensure that the packages ``bar`` and ``baz`` get built, the
+   previous ``RDEPENDS`` assignment also causes a task dependency to be
+   added. This dependency is from the recipe's
+   ```do_build`` <#ref-tasks-build>`__ (not to be confused with
+   ```do_compile`` <#ref-tasks-compile>`__) task to the
+   ``do_package_write_*`` task of the recipes that build ``bar`` and
+   ``baz``.
+   The names of the packages you list within ``RDEPENDS`` must be the
+   names of other packages - they cannot be recipe names. Although
+   package names and recipe names usually match, the important point
+   here is that you are providing package names within the ``RDEPENDS``
+   variable. For an example of the default list of packages created from
+   a recipe, see the ```PACKAGES`` <#var-PACKAGES>`__ variable.
+   Because the ``RDEPENDS`` variable applies to packages being built,
+   you should always use the variable in a form with an attached package
+   name (remember that a single recipe can build multiple packages). For
+   example, suppose you are building a development package that depends
+   on the ``perl`` package. In this case, you would use the following
+   ``RDEPENDS`` statement: RDEPENDS_${PN}-dev += "perl" In the example,
+   the development package depends on the ``perl`` package. Thus, the
+   ``RDEPENDS`` variable has the ``${PN}-dev`` package name as part of
+   the variable.
+   .. note::
+      RDEPENDS_${PN}-dev
+      includes
+      ${
+      PN
+      }
+      by default. This default is set in the BitBake configuration file
+      (
+      meta/conf/bitbake.conf
+      ). Be careful not to accidentally remove
+      ${PN}
+      when modifying
+      RDEPENDS_${PN}-dev
+      . Use the "+=" operator rather than the "=" operator.
+   The package names you use with ``RDEPENDS`` must appear as they would
+   in the ``PACKAGES`` variable. The ```PKG`` <#var-PKG>`__ variable
+   allows a different name to be used for the final package (e.g. the
+   ```debian`` <#ref-classes-debian>`__ class uses this to rename
+   packages), but this final package name cannot be used with
+   ``RDEPENDS``, which makes sense as ``RDEPENDS`` is meant to be
+   independent of the package format used.
+   BitBake, which the OpenEmbedded build system uses, supports
+   specifying versioned dependencies. Although the syntax varies
+   depending on the packaging format, BitBake hides these differences
+   from you. Here is the general syntax to specify versions with the
+   ``RDEPENDS`` variable: RDEPENDS_${PN} = "package (operator version)"
+   For operator, you can specify the following: = < > <= >= For version,
+   provide the version number.
+   .. note::
+      You can use
+      EXTENDPKGV
+      to provide a full package version specification.
+   For example, the following sets up a dependency on version 1.2 or
+   greater of the package ``foo``: RDEPENDS_${PN} = "foo (>= 1.2)"
+   For information on build-time dependencies, see the
+   ```DEPENDS`` <#var-DEPENDS>`__ variable. You can also see the
+   "`Tasks <&YOCTO_DOCS_BB_URL;#tasks>`__" and
+   "`Dependencies <&YOCTO_DOCS_BB_URL;#dependencies>`__" sections in the
+   BitBake User Manual for additional information on tasks and
+   dependencies.
+REQUIRED_DISTRO_FEATURES
+   When inheriting the
+   ```distro_features_check`` <#ref-classes-distro_features_check>`__
+   class, this variable identifies distribution features that must exist
+   in the current configuration in order for the OpenEmbedded build
+   system to build the recipe. In other words, if the
+   ``REQUIRED_DISTRO_FEATURES`` variable lists a feature that does not
+   appear in ``DISTRO_FEATURES`` within the current configuration, an
+   error occurs and the build stops.
+RM_WORK_EXCLUDE
+   With ``rm_work`` enabled, this variable specifies a list of recipes
+   whose work directories should not be removed. See the
+   "```rm_work.bbclass`` <#ref-classes-rm-work>`__" section for more
+   details.
+ROOT_HOME
+   Defines the root home directory. By default, this directory is set as
+   follows in the BitBake configuration file: ROOT_HOME ??= "/home/root"
+   .. note::
+      This default value is likely used because some embedded solutions
+      prefer to have a read-only root filesystem and prefer to keep
+      writeable data in one place.
+   You can override the default by setting the variable in any layer or
+   in the ``local.conf`` file. Because the default is set using a "weak"
+   assignment (i.e. "??="), you can use either of the following forms to
+   define your override: ROOT_HOME = "/root" ROOT_HOME ?= "/root" These
+   override examples use ``/root``, which is probably the most commonly
+   used override.
+ROOTFS
+   Indicates a filesystem image to include as the root filesystem.
+   The ``ROOTFS`` variable is an optional variable used with the
+   ```image-live`` <#ref-classes-image-live>`__ class.
+ROOTFS_POSTINSTALL_COMMAND
+   Specifies a list of functions to call after the OpenEmbedded build
+   system has installed packages. You can specify functions separated by
+   semicolons: ROOTFS_POSTINSTALL_COMMAND += "function; ... "
+   If you need to pass the root filesystem path to a command within a
+   function, you can use ``${IMAGE_ROOTFS}``, which points to the
+   directory that becomes the root filesystem image. See the
+   ```IMAGE_ROOTFS`` <#var-IMAGE_ROOTFS>`__ variable for more
+   information.
+ROOTFS_POSTPROCESS_COMMAND
+   Specifies a list of functions to call once the OpenEmbedded build
+   system has created the root filesystem. You can specify functions
+   separated by semicolons: ROOTFS_POSTPROCESS_COMMAND += "function; ...
+   "
+   If you need to pass the root filesystem path to a command within a
+   function, you can use ``${IMAGE_ROOTFS}``, which points to the
+   directory that becomes the root filesystem image. See the
+   ```IMAGE_ROOTFS`` <#var-IMAGE_ROOTFS>`__ variable for more
+   information.
+ROOTFS_POSTUNINSTALL_COMMAND
+   Specifies a list of functions to call after the OpenEmbedded build
+   system has removed unnecessary packages. When runtime package
+   management is disabled in the image, several packages are removed
+   including ``base-passwd``, ``shadow``, and ``update-alternatives``.
+   You can specify functions separated by semicolons:
+   ROOTFS_POSTUNINSTALL_COMMAND += "function; ... "
+   If you need to pass the root filesystem path to a command within a
+   function, you can use ``${IMAGE_ROOTFS}``, which points to the
+   directory that becomes the root filesystem image. See the
+   ```IMAGE_ROOTFS`` <#var-IMAGE_ROOTFS>`__ variable for more
+   information.
+ROOTFS_PREPROCESS_COMMAND
+   Specifies a list of functions to call before the OpenEmbedded build
+   system has created the root filesystem. You can specify functions
+   separated by semicolons: ROOTFS_PREPROCESS_COMMAND += "function; ...
+   "
+   If you need to pass the root filesystem path to a command within a
+   function, you can use ``${IMAGE_ROOTFS}``, which points to the
+   directory that becomes the root filesystem image. See the
+   ```IMAGE_ROOTFS`` <#var-IMAGE_ROOTFS>`__ variable for more
+   information.
+RPROVIDES
+   A list of package name aliases that a package also provides. These
+   aliases are useful for satisfying runtime dependencies of other
+   packages both during the build and on the target (as specified by
+   ``RDEPENDS``).
+   .. note::
+      A package's own name is implicitly already in its
+      RPROVIDES
+      list.
+   As with all package-controlling variables, you must always use the
+   variable in conjunction with a package name override. Here is an
+   example: RPROVIDES_${PN} = "widget-abi-2"
+RRECOMMENDS
+   A list of packages that extends the usability of a package being
+   built. The package being built does not depend on this list of
+   packages in order to successfully build, but rather uses them for
+   extended usability. To specify runtime dependencies for packages, see
+   the ``RDEPENDS`` variable.
+   The package manager will automatically install the ``RRECOMMENDS``
+   list of packages when installing the built package. However, you can
+   prevent listed packages from being installed by using the
+   ```BAD_RECOMMENDATIONS`` <#var-BAD_RECOMMENDATIONS>`__,
+   ```NO_RECOMMENDATIONS`` <#var-NO_RECOMMENDATIONS>`__, and
+   ```PACKAGE_EXCLUDE`` <#var-PACKAGE_EXCLUDE>`__ variables.
+   Packages specified in ``RRECOMMENDS`` need not actually be produced.
+   However, a recipe must exist that provides each package, either
+   through the ```PACKAGES`` <#var-PACKAGES>`__ or
+   ```PACKAGES_DYNAMIC`` <#var-PACKAGES_DYNAMIC>`__ variables or the
+   ```RPROVIDES`` <#var-RPROVIDES>`__ variable, or an error will occur
+   during the build. If such a recipe does exist and the package is not
+   produced, the build continues without error.
+   Because the ``RRECOMMENDS`` variable applies to packages being built,
+   you should always attach an override to the variable to specify the
+   particular package whose usability is being extended. For example,
+   suppose you are building a development package that is extended to
+   support wireless functionality. In this case, you would use the
+   following: RRECOMMENDS_${PN}-dev += "wireless_package_name" In the
+   example, the package name (``${PN}-dev``) must appear as it would in
+   the ``PACKAGES`` namespace before any renaming of the output package
+   by classes such as ``debian.bbclass``.
+   BitBake, which the OpenEmbedded build system uses, supports
+   specifying versioned recommends. Although the syntax varies depending
+   on the packaging format, BitBake hides these differences from you.
+   Here is the general syntax to specify versions with the
+   ``RRECOMMENDS`` variable: RRECOMMENDS_${PN} = "package (operator
+   version)" For ``operator``, you can specify the following: = < > <=
+   >= For example, the following sets up a recommend on version 1.2 or
+   greater of the package ``foo``: RRECOMMENDS_${PN} = "foo (>= 1.2)"
+RREPLACES
+   A list of packages replaced by a package. The package manager uses
+   this variable to determine which package should be installed to
+   replace other package(s) during an upgrade. In order to also have the
+   other package(s) removed at the same time, you must add the name of
+   the other package to the ``RCONFLICTS`` variable.
+   As with all package-controlling variables, you must use this variable
+   in conjunction with a package name override. Here is an example:
+   RREPLACES_${PN} = "other_package_being_replaced"
+   BitBake, which the OpenEmbedded build system uses, supports
+   specifying versioned replacements. Although the syntax varies
+   depending on the packaging format, BitBake hides these differences
+   from you. Here is the general syntax to specify versions with the
+   ``RREPLACES`` variable: RREPLACES_${PN} = "package (operator
+   version)" For ``operator``, you can specify the following: = < > <=
+   >= For example, the following sets up a replacement using version 1.2
+   or greater of the package ``foo``: RREPLACES_${PN} = "foo (>= 1.2)"
+RSUGGESTS
+   A list of additional packages that you can suggest for installation
+   by the package manager at the time a package is installed. Not all
+   package managers support this functionality.
+   As with all package-controlling variables, you must always use this
+   variable in conjunction with a package name override. Here is an
+   example: RSUGGESTS_${PN} = "useful_package another_package"
+S
+   The location in the `Build Directory <#build-directory>`__ where
+   unpacked recipe source code resides. By default, this directory is
+   ``${``\ ```WORKDIR`` <#var-WORKDIR>`__\ ``}/${``\ ```BPN`` <#var-BPN>`__\ ``}-${``\ ```PV`` <#var-PV>`__\ ``}``,
+   where ``${BPN}`` is the base recipe name and ``${PV}`` is the recipe
+   version. If the source tarball extracts the code to a directory named
+   anything other than ``${BPN}-${PV}``, or if the source code is
+   fetched from an SCM such as Git or Subversion, then you must set
+   ``S`` in the recipe so that the OpenEmbedded build system knows where
+   to find the unpacked source.
+   As an example, assume a `Source Directory <#source-directory>`__
+   top-level folder named ``poky`` and a default Build Directory at
+   ``poky/build``. In this case, the work directory the build system
+   uses to keep the unpacked recipe for ``db`` is the following:
+   poky/build/tmp/work/qemux86-poky-linux/db/5.1.19-r3/db-5.1.19 The
+   unpacked source code resides in the ``db-5.1.19`` folder.
+   This next example assumes a Git repository. By default, Git
+   repositories are cloned to ``${WORKDIR}/git`` during
+   ```do_fetch`` <#ref-tasks-fetch>`__. Since this path is different
+   from the default value of ``S``, you must set it specifically so the
+   source can be located: SRC_URI = "git://path/to/repo.git" S =
+   "${WORKDIR}/git"
+SANITY_REQUIRED_UTILITIES
+   Specifies a list of command-line utilities that should be checked for
+   during the initial sanity checking process when running BitBake. If
+   any of the utilities are not installed on the build host, then
+   BitBake immediately exits with an error.
+SANITY_TESTED_DISTROS
+   A list of the host distribution identifiers that the build system has
+   been tested against. Identifiers consist of the host distributor ID
+   followed by the release, as reported by the ``lsb_release`` tool or
+   as read from ``/etc/lsb-release``. Separate the list items with
+   explicit newline characters (``\n``). If ``SANITY_TESTED_DISTROS`` is
+   not empty and the current value of
+   ```NATIVELSBSTRING`` <#var-NATIVELSBSTRING>`__ does not appear in the
+   list, then the build system reports a warning that indicates the
+   current host distribution has not been tested as a build host.
+SDK_ARCH
+   The target architecture for the SDK. Typically, you do not directly
+   set this variable. Instead, use ```SDKMACHINE`` <#var-SDKMACHINE>`__.
+SDK_DEPLOY
+   The directory set up and used by the
+   ```populate_sdk_base`` <#ref-classes-populate-sdk>`__ class to which
+   the SDK is deployed. The ``populate_sdk_base`` class defines
+   ``SDK_DEPLOY`` as follows: SDK_DEPLOY = "${TMPDIR}/deploy/sdk"
+SDK_DIR
+   The parent directory used by the OpenEmbedded build system when
+   creating SDK output. The
+   ```populate_sdk_base`` <#ref-classes-populate-sdk-*>`__ class defines
+   the variable as follows: SDK_DIR = "${WORKDIR}/sdk"
+   .. note::
+      The
+      SDK_DIR
+      directory is a temporary directory as it is part of
+      WORKDIR
+      . The final output directory is
+      SDK_DEPLOY
+      .
+SDK_EXT_TYPE
+   Controls whether or not shared state artifacts are copied into the
+   extensible SDK. The default value of "full" copies all of the
+   required shared state artifacts into the extensible SDK. The value
+   "minimal" leaves these artifacts out of the SDK.
+   .. note::
+      If you set the variable to "minimal", you need to ensure
+      SSTATE_MIRRORS
+      is set in the SDK's configuration to enable the artifacts to be
+      fetched as needed.
+SDK_HOST_MANIFEST
+   The manifest file for the host part of the SDK. This file lists all
+   the installed packages that make up the host part of the SDK. The
+   file contains package information on a line-per-package basis as
+   follows: packagename packagearch version
+   The ```populate_sdk_base`` <#ref-classes-populate-sdk-*>`__ class
+   defines the manifest file as follows: SDK_HOST_MANIFEST =
+   "${SDK_DEPLOY}/${TOOLCHAIN_OUTPUTNAME}.host.manifest" The location is
+   derived using the ```SDK_DEPLOY`` <#var-SDK_DEPLOY>`__ and
+   ```TOOLCHAIN_OUTPUTNAME`` <#var-TOOLCHAIN_OUTPUTNAME>`__ variables.
+SDK_INCLUDE_PKGDATA
+   When set to "1", specifies to include the packagedata for all recipes
+   in the "world" target in the extensible SDK. Including this data
+   allows the ``devtool search`` command to find these recipes in search
+   results, as well as allows the ``devtool add`` command to map
+   dependencies more effectively.
+   .. note::
+      Enabling the
+      SDK_INCLUDE_PKGDATA
+      variable significantly increases build time because all of world
+      needs to be built. Enabling the variable also slightly increases
+      the size of the extensible SDK.
+SDK_INCLUDE_TOOLCHAIN
+   When set to "1", specifies to include the toolchain in the extensible
+   SDK. Including the toolchain is useful particularly when
+   ```SDK_EXT_TYPE`` <#var-SDK_EXT_TYPE>`__ is set to "minimal" to keep
+   the SDK reasonably small but you still want to provide a usable
+   toolchain. For example, suppose you want to use the toolchain from an
+   IDE or from other tools and you do not want to perform additional
+   steps to install the toolchain.
+   The ``SDK_INCLUDE_TOOLCHAIN`` variable defaults to "0" if
+   ``SDK_EXT_TYPE`` is set to "minimal", and defaults to "1" if
+   ``SDK_EXT_TYPE`` is set to "full".
+SDK_INHERIT_BLACKLIST
+   A list of classes to remove from the ```INHERIT`` <#var-INHERIT>`__
+   value globally within the extensible SDK configuration. The
+   ```populate-sdk-ext`` <#ref-classes-populate-sdk-*>`__ class sets the
+   default value: SDK_INHERIT_BLACKLIST ?= "buildhistory icecc"
+   Some classes are not generally applicable within the extensible SDK
+   context. You can use this variable to disable those classes.
+   For additional information on how to customize the extensible SDK's
+   configuration, see the "`Configuring the Extensible
+   SDK <&YOCTO_DOCS_SDK_URL;#sdk-configuring-the-extensible-sdk>`__"
+   section in the Yocto Project Application Development and the
+   Extensible Software Development Kit (eSDK) manual.
+SDK_LOCAL_CONF_BLACKLIST
+   A list of variables not allowed through from the OpenEmbedded build
+   system configuration into the extensible SDK configuration. Usually,
+   these are variables that are specific to the machine on which the
+   build system is running and thus would be potentially problematic
+   within the extensible SDK.
+   By default, ``SDK_LOCAL_CONF_BLACKLIST`` is set in the
+   ```populate-sdk-ext`` <#ref-classes-populate-sdk-*>`__ class and
+   excludes the following variables:
+   `CONF_VERSION <#var-CONF_VERSION>`__
+   `BB_NUMBER_THREADS <#var-BB_NUMBER_THREADS>`__
+   `BB_NUMBER_PARSE_THREADS <&YOCTO_DOCS_BB_URL;#var-BB_NUMBER_PARSE_THREADS>`__
+   `PARALLEL_MAKE <#var-PARALLEL_MAKE>`__
+   `PRSERV_HOST <#var-PRSERV_HOST>`__
+   `SSTATE_MIRRORS <#var-SSTATE_MIRRORS>`__ `DL_DIR <#var-DL_DIR>`__
+   `SSTATE_DIR <#var-SSTATE_DIR>`__ `TMPDIR <#var-TMPDIR>`__
+   `BB_SERVER_TIMEOUT <#var-BB_SERVER_TIMEOUT>`__
+   For additional information on how to customize the extensible SDK's
+   configuration, see the "`Configuring the Extensible
+   SDK <&YOCTO_DOCS_SDK_URL;#sdk-configuring-the-extensible-sdk>`__"
+   section in the Yocto Project Application Development and the
+   Extensible Software Development Kit (eSDK) manual.
+SDK_LOCAL_CONF_WHITELIST
+   A list of variables allowed through from the OpenEmbedded build
+   system configuration into the extensible SDK configuration. By
+   default, the list of variables is empty and is set in the
+   ```populate-sdk-ext`` <#ref-classes-populate-sdk-*>`__ class.
+   This list overrides the variables specified using the
+   ```SDK_LOCAL_CONF_BLACKLIST`` <#var-SDK_LOCAL_CONF_BLACKLIST>`__
+   variable as well as any variables identified by automatic
+   blacklisting due to the "/" character being found at the start of the
+   value, which is usually indicative of being a path and thus might not
+   be valid on the system where the SDK is installed.
+   For additional information on how to customize the extensible SDK's
+   configuration, see the "`Configuring the Extensible
+   SDK <&YOCTO_DOCS_SDK_URL;#sdk-configuring-the-extensible-sdk>`__"
+   section in the Yocto Project Application Development and the
+   Extensible Software Development Kit (eSDK) manual.
+SDK_NAME
+   The base name for SDK output files. The name is derived from the
+   ```DISTRO`` <#var-DISTRO>`__, ```TCLIBC`` <#var-TCLIBC>`__,
+   ```SDK_ARCH`` <#var-SDK_ARCH>`__,
+   ```IMAGE_BASENAME`` <#var-IMAGE_BASENAME>`__, and
+   ```TUNE_PKGARCH`` <#var-TUNE_PKGARCH>`__ variables: SDK_NAME =
+   "${DISTRO}-${TCLIBC}-${SDK_ARCH}-${IMAGE_BASENAME}-${TUNE_PKGARCH}"
+SDK_OS
+   Specifies the operating system for which the SDK will be built. The
+   default value is the value of ```BUILD_OS`` <#var-BUILD_OS>`__.
+SDK_OUTPUT
+   The location used by the OpenEmbedded build system when creating SDK
+   output. The ```populate_sdk_base`` <#ref-classes-populate-sdk-*>`__
+   class defines the variable as follows: SDK_DIR = "${WORKDIR}/sdk"
+   SDK_OUTPUT = "${SDK_DIR}/image" SDK_DEPLOY = "${DEPLOY_DIR}/sdk"
+   .. note::
+      The
+      SDK_OUTPUT
+      directory is a temporary directory as it is part of
+      WORKDIR
+      by way of
+      SDK_DIR
+      . The final output directory is
+      SDK_DEPLOY
+      .
+SDK_PACKAGE_ARCHS
+   Specifies a list of architectures compatible with the SDK machine.
+   This variable is set automatically and should not normally be
+   hand-edited. Entries are separated using spaces and listed in order
+   of priority. The default value for ``SDK_PACKAGE_ARCHS`` is "all any
+   noarch ${SDK_ARCH}-${SDKPKGSUFFIX}".
+SDK_POSTPROCESS_COMMAND
+   Specifies a list of functions to call once the OpenEmbedded build
+   system creates the SDK. You can specify functions separated by
+   semicolons: SDK_POSTPROCESS_COMMAND += "function; ... "
+   If you need to pass an SDK path to a command within a function, you
+   can use ``${SDK_DIR}``, which points to the parent directory used by
+   the OpenEmbedded build system when creating SDK output. See the
+   ```SDK_DIR`` <#var-SDK_DIR>`__ variable for more information.
+SDK_PREFIX
+   The toolchain binary prefix used for ``nativesdk`` recipes. The
+   OpenEmbedded build system uses the ``SDK_PREFIX`` value to set the
+   ```TARGET_PREFIX`` <#var-TARGET_PREFIX>`__ when building
+   ``nativesdk`` recipes. The default value is "${SDK_SYS}-".
+SDK_RECRDEP_TASKS
+   A list of shared state tasks added to the extensible SDK. By default,
+   the following tasks are added: do_populate_lic do_package_qa
+   do_populate_sysroot do_deploy Despite the default value of "" for the
+   ``SDK_RECRDEP_TASKS`` variable, the above four tasks are always added
+   to the SDK. To specify tasks beyond these four, you need to use the
+   ``SDK_RECRDEP_TASKS`` variable (e.g. you are defining additional
+   tasks that are needed in order to build
+   ```SDK_TARGETS`` <#var-SDK_TARGETS>`__).
+SDK_SYS
+   Specifies the system, including the architecture and the operating
+   system, for which the SDK will be built.
+   The OpenEmbedded build system automatically sets this variable based
+   on ```SDK_ARCH`` <#var-SDK_ARCH>`__,
+   ```SDK_VENDOR`` <#var-SDK_VENDOR>`__, and
+   ```SDK_OS`` <#var-SDK_OS>`__. You do not need to set the ``SDK_SYS``
+   variable yourself.
+SDK_TARGET_MANIFEST
+   The manifest file for the target part of the SDK. This file lists all
+   the installed packages that make up the target part of the SDK. The
+   file contains package information on a line-per-package basis as
+   follows: packagename packagearch version
+   The ```populate_sdk_base`` <#ref-classes-populate-sdk-*>`__ class
+   defines the manifest file as follows: SDK_TARGET_MANIFEST =
+   "${SDK_DEPLOY}/${TOOLCHAIN_OUTPUTNAME}.target.manifest" The location
+   is derived using the ```SDK_DEPLOY`` <#var-SDK_DEPLOY>`__ and
+   ```TOOLCHAIN_OUTPUTNAME`` <#var-TOOLCHAIN_OUTPUTNAME>`__ variables.
+SDK_TARGETS
+   A list of targets to install from shared state as part of the
+   standard or extensible SDK installation. The default value is "${PN}"
+   (i.e. the image from which the SDK is built).
+   The ``SDK_TARGETS`` variable is an internal variable and typically
+   would not be changed.
+SDK_TITLE
+   The title to be printed when running the SDK installer. By default,
+   this title is based on the ```DISTRO_NAME`` <#var-DISTRO_NAME>`__ or
+   ```DISTRO`` <#var-DISTRO>`__ variable and is set in the
+   ```populate_sdk_base`` <#ref-classes-populate-sdk-*>`__ class as
+   follows: SDK_TITLE ??= "${@d.getVar('DISTRO_NAME') or
+   d.getVar('DISTRO')} SDK" For the default distribution "poky",
+   ``SDK_TITLE`` is set to "Poky (Yocto Project Reference Distro)".
+   For information on how to change this default title, see the
+   "`Changing the Extensible SDK Installer
+   Title <&YOCTO_DOCS_SDK_URL;#sdk-changing-the-sdk-installer-title>`__"
+   section in the Yocto Project Application Development and the
+   Extensible Software Development Kit (eSDK) manual.
+SDK_UPDATE_URL
+   An optional URL for an update server for the extensible SDK. If set,
+   the value is used as the default update server when running
+   ``devtool sdk-update`` within the extensible SDK.
+SDK_VENDOR
+   Specifies the name of the SDK vendor.
+SDK_VERSION
+   Specifies the version of the SDK. The distribution configuration file
+   (e.g. ``/meta-poky/conf/distro/poky.conf``) defines the
+   ``SDK_VERSION`` as follows: SDK_VERSION =
+   "${@d.getVar('DISTRO_VERSION').replace('snapshot-${DATE}','snapshot')}"
+   For additional information, see the
+   ```DISTRO_VERSION`` <#var-DISTRO_VERSION>`__ and
+   ```DATE`` <#var-DATE>`__ variables.
+SDKEXTPATH
+   The default installation directory for the Extensible SDK. By
+   default, this directory is based on the ```DISTRO`` <#var-DISTRO>`__
+   variable and is set in the
+   ```populate_sdk_base`` <#ref-classes-populate-sdk-*>`__ class as
+   follows: SDKEXTPATH ??= "~/${@d.getVar('DISTRO')}_sdk" For the
+   default distribution "poky", the ``SDKEXTPATH`` is set to "poky_sdk".
+   For information on how to change this default directory, see the
+   "`Changing the Default SDK Installation
+   Directory <&YOCTO_DOCS_SDK_URL;#sdk-changing-the-default-sdk-installation-directory>`__"
+   section in the Yocto Project Application Development and the
+   Extensible Software Development Kit (eSDK) manual.
+SDKIMAGE_FEATURES
+   Equivalent to ``IMAGE_FEATURES``. However, this variable applies to
+   the SDK generated from an image using the following command: $
+   bitbake -c populate_sdk imagename
+SDKMACHINE
+   The machine for which the SDK is built. In other words, the SDK is
+   built such that it runs on the target you specify with the
+   ``SDKMACHINE`` value. The value points to a corresponding ``.conf``
+   file under ``conf/machine-sdk/``.
+   You can use "i686" and "x86_64" as possible values for this variable.
+   The variable defaults to "i686" and is set in the local.conf file in
+   the Build Directory. SDKMACHINE ?= "i686"
+   .. note::
+      You cannot set the
+      SDKMACHINE
+      variable in your distribution configuration file. If you do, the
+      configuration will not take affect.
+SDKPATH
+   Defines the path offered to the user for installation of the SDK that
+   is generated by the OpenEmbedded build system. The path appears as
+   the default location for installing the SDK when you run the SDK's
+   installation script. You can override the offered path when you run
+   the script.
+SDKTARGETSYSROOT
+   The full path to the sysroot used for cross-compilation within an SDK
+   as it will be when installed into the default
+   ```SDKPATH`` <#var-SDKPATH>`__.
+SECTION
+   The section in which packages should be categorized. Package
+   management utilities can make use of this variable.
+SELECTED_OPTIMIZATION
+   Specifies the optimization flags passed to the C compiler when
+   building for the target. The flags are passed through the default
+   value of the ```TARGET_CFLAGS`` <#var-TARGET_CFLAGS>`__ variable.
+   The ``SELECTED_OPTIMIZATION`` variable takes the value of
+   ``FULL_OPTIMIZATION`` unless ``DEBUG_BUILD`` = "1". If that is the
+   case, the value of ``DEBUG_OPTIMIZATION`` is used.
+SERIAL_CONSOLE
+   Defines a serial console (TTY) to enable using
+   `getty <https://en.wikipedia.org/wiki/Getty_(Unix)>`__. Provide a
+   value that specifies the baud rate followed by the TTY device name
+   separated by a space. You cannot specify more than one TTY device:
+   SERIAL_CONSOLE = "115200 ttyS0"
+   .. note::
+      The
+      SERIAL_CONSOLE
+      variable is deprecated. Please use the
+      SERIAL_CONSOLES
+      variable.
+SERIAL_CONSOLES
+   Defines a serial console (TTY) to enable using
+   `getty <https://en.wikipedia.org/wiki/Getty_(Unix)>`__. Provide a
+   value that specifies the baud rate followed by the TTY device name
+   separated by a semicolon. Use spaces to separate multiple devices:
+   SERIAL_CONSOLES = "115200;ttyS0 115200;ttyS1"
+SERIAL_CONSOLES_CHECK
+   Specifies serial consoles, which must be listed in
+   ```SERIAL_CONSOLES`` <#var-SERIAL_CONSOLES>`__, to check against
+   ``/proc/console`` before enabling them using getty. This variable
+   allows aliasing in the format: <device>:<alias>. If a device was
+   listed as "sclp_line0" in ``/dev/`` and "ttyS0" was listed in
+   ``/proc/console``, you would do the following: SERIAL_CONSOLES_CHECK
+   = "slcp_line0:ttyS0" This variable is currently only supported with
+   SysVinit (i.e. not with systemd).
+SIGGEN_EXCLUDE_SAFE_RECIPE_DEPS
+   A list of recipe dependencies that should not be used to determine
+   signatures of tasks from one recipe when they depend on tasks from
+   another recipe. For example: SIGGEN_EXCLUDE_SAFE_RECIPE_DEPS +=
+   "intone->mplayer2"
+   In the previous example, ``intone`` depends on ``mplayer2``.
+   You can use the special token ``"*"`` on the left-hand side of the
+   dependency to match all recipes except the one on the right-hand
+   side. Here is an example: SIGGEN_EXCLUDE_SAFE_RECIPE_DEPS +=
+   "*->quilt-native"
+   In the previous example, all recipes except ``quilt-native`` ignore
+   task signatures from the ``quilt-native`` recipe when determining
+   their task signatures.
+   Use of this variable is one mechanism to remove dependencies that
+   affect task signatures and thus force rebuilds when a recipe changes.
+   .. note::
+      If you add an inappropriate dependency for a recipe relationship,
+      the software might break during runtime if the interface of the
+      second recipe was changed after the first recipe had been built.
+SIGGEN_EXCLUDERECIPES_ABISAFE
+   A list of recipes that are completely stable and will never change.
+   The ABI for the recipes in the list are presented by output from the
+   tasks run to build the recipe. Use of this variable is one way to
+   remove dependencies from one recipe on another that affect task
+   signatures and thus force rebuilds when the recipe changes.
+   .. note::
+      If you add an inappropriate variable to this list, the software
+      might break at runtime if the interface of the recipe was changed
+      after the other had been built.
+SITEINFO_BITS
+   Specifies the number of bits for the target system CPU. The value
+   should be either "32" or "64".
+SITEINFO_ENDIANNESS
+   Specifies the endian byte order of the target system. The value
+   should be either "le" for little-endian or "be" for big-endian.
+SKIP_FILEDEPS
+   Enables removal of all files from the "Provides" section of an RPM
+   package. Removal of these files is required for packages containing
+   prebuilt binaries and libraries such as ``libstdc++`` and ``glibc``.
+   To enable file removal, set the variable to "1" in your
+   ``conf/local.conf`` configuration file in your: `Build
+   Directory <#build-directory>`__. SKIP_FILEDEPS = "1"
+SOC_FAMILY
+   Groups together machines based upon the same family of SOC (System On
+   Chip). You typically set this variable in a common ``.inc`` file that
+   you include in the configuration files of all the machines.
+   .. note::
+      You must include
+      conf/machine/include/soc-family.inc
+      for this variable to appear in
+      MACHINEOVERRIDES
+      .
+SOLIBS
+   Defines the suffix for shared libraries used on the target platform.
+   By default, this suffix is ".so.*" for all Linux-based systems and is
+   defined in the ``meta/conf/bitbake.conf`` configuration file.
+   You will see this variable referenced in the default values of
+   ``FILES_${PN}``.
+SOLIBSDEV
+   Defines the suffix for the development symbolic link (symlink) for
+   shared libraries on the target platform. By default, this suffix is
+   ".so" for Linux-based systems and is defined in the
+   ``meta/conf/bitbake.conf`` configuration file.
+   You will see this variable referenced in the default values of
+   ``FILES_${PN}-dev``.
+SOURCE_MIRROR_FETCH
+   When you are fetching files to create a mirror of sources (i.e.
+   creating a source mirror), setting ``SOURCE_MIRROR_FETCH`` to "1" in
+   your ``local.conf`` configuration file ensures the source for all
+   recipes are fetched regardless of whether or not a recipe is
+   compatible with the configuration. A recipe is considered
+   incompatible with the currently configured machine when either or
+   both the ```COMPATIBLE_MACHINE`` <#var-COMPATIBLE_MACHINE>`__
+   variable and ```COMPATIBLE_HOST`` <#var-COMPATIBLE_HOST>`__ variables
+   specify compatibility with a machine other than that of the current
+   machine or host.
+   .. note::
+      Do not set the
+      SOURCE_MIRROR_FETCH
+      variable unless you are creating a source mirror. In other words,
+      do not set the variable during a normal build.
+SOURCE_MIRROR_URL
+   Defines your own ```PREMIRRORS`` <#var-PREMIRRORS>`__ from which to
+   first fetch source before attempting to fetch from the upstream
+   specified in ```SRC_URI`` <#var-SRC_URI>`__.
+   To use this variable, you must globally inherit the
+   ```own-mirrors`` <#ref-classes-own-mirrors>`__ class and then provide
+   the URL to your mirrors. Here is the general syntax: INHERIT +=
+   "own-mirrors" SOURCE_MIRROR_URL =
+   "http://example.com/my_source_mirror"
+   .. note::
+      You can specify only a single URL in
+      SOURCE_MIRROR_URL
+      .
+SPDXLICENSEMAP
+   Maps commonly used license names to their SPDX counterparts found in
+   ``meta/files/common-licenses/``. For the default ``SPDXLICENSEMAP``
+   mappings, see the ``meta/conf/licenses.conf`` file.
+   For additional information, see the ```LICENSE`` <#var-LICENSE>`__
+   variable.
+SPECIAL_PKGSUFFIX
+   A list of prefixes for ```PN`` <#var-PN>`__ used by the OpenEmbedded
+   build system to create variants of recipes or packages. The list
+   specifies the prefixes to strip off during certain circumstances such
+   as the generation of the ```BPN`` <#var-BPN>`__ variable.
+SPL_BINARY
+   The file type for the Secondary Program Loader (SPL). Some devices
+   use an SPL from which to boot (e.g. the BeagleBone development
+   board). For such cases, you can declare the file type of the SPL
+   binary in the ``u-boot.inc`` include file, which is used in the
+   U-Boot recipe.
+   The SPL file type is set to "null" by default in the ``u-boot.inc``
+   file as follows: # Some versions of u-boot build an SPL (Second
+   Program Loader) image that # should be packaged along with the u-boot
+   binary as well as placed in the # deploy directory. For those
+   versions they can set the following variables # to allow packaging
+   the SPL. SPL_BINARY ?= "" SPL_BINARYNAME ?=
+   "${@os.path.basename(d.getVar("SPL_BINARY"))}" SPL_IMAGE ?=
+   "${SPL_BINARYNAME}-${MACHINE}-${PV}-${PR}" SPL_SYMLINK ?=
+   "${SPL_BINARYNAME}-${MACHINE}" The ``SPL_BINARY`` variable helps form
+   various ``SPL_*`` variables used by the OpenEmbedded build system.
+   See the BeagleBone machine configuration example in the "`Creating a
+   new BSP Layer Using the ``bitbake-layers``
+   Script <&YOCTO_DOCS_BSP_URL;#creating-a-new-bsp-layer-using-the-bitbake-layers-script>`__"
+   section in the Yocto Project Board Support Package Developer's Guide
+   for additional information.
+SRC_URI
+   The list of source files - local or remote. This variable tells the
+   OpenEmbedded build system which bits to pull in for the build and how
+   to pull them in. For example, if the recipe or append file only needs
+   to fetch a tarball from the Internet, the recipe or append file uses
+   a single ``SRC_URI`` entry. On the other hand, if the recipe or
+   append file needs to fetch a tarball, apply two patches, and include
+   a custom file, the recipe or append file would include four instances
+   of the variable.
+   The following list explains the available URI protocols. URI
+   protocols are highly dependent on particular BitBake Fetcher
+   submodules. Depending on the fetcher BitBake uses, various URL
+   parameters are employed. For specifics on the supported Fetchers, see
+   the "`Fetchers <&YOCTO_DOCS_BB_URL;#bb-fetchers>`__" section in the
+   BitBake User Manual.
+   -  *``file://`` -* Fetches files, which are usually files shipped
+      with the `Metadata <#metadata>`__, from the local machine (e.g.
+      `patch <&YOCTO_DOCS_OM_URL;#patching-dev-environment>`__ files).
+      The path is relative to the ```FILESPATH`` <#var-FILESPATH>`__
+      variable. Thus, the build system searches, in order, from the
+      following directories, which are assumed to be a subdirectories of
+      the directory in which the recipe file (``.bb``) or append file
+      (``.bbappend``) resides:
+      -  *``${BPN}`` -* The base recipe name without any special suffix
+         or version numbers.
+      -  *``${BP}`` -* ``${BPN}-${PV}``. The base recipe name and
+         version but without any special package name suffix.
+      -  *files -* Files within a directory, which is named ``files``
+         and is also alongside the recipe or append file.
+      .. note::
+         If you want the build system to pick up files specified through
+         a
+         SRC_URI
+         statement from your append file, you need to be sure to extend
+         the
+         FILESPATH
+         variable by also using the
+         FILESEXTRAPATHS
+         variable from within your append file.
+   -  *``bzr://`` -* Fetches files from a Bazaar revision control
+      repository.
+   -  *``git://`` -* Fetches files from a Git revision control
+      repository.
+   -  *``osc://`` -* Fetches files from an OSC (OpenSUSE Build service)
+      revision control repository.
+   -  *``repo://`` -* Fetches files from a repo (Git) repository.
+   -  *``ccrc://`` -* Fetches files from a ClearCase repository.
+   -  *``http://`` -* Fetches files from the Internet using ``http``.
+   -  *``https://`` -* Fetches files from the Internet using ``https``.
+   -  *``ftp://`` -* Fetches files from the Internet using ``ftp``.
+   -  *``cvs://`` -* Fetches files from a CVS revision control
+      repository.
+   -  *``hg://`` -* Fetches files from a Mercurial (``hg``) revision
+      control repository.
+   -  *``p4://`` -* Fetches files from a Perforce (``p4``) revision
+      control repository.
+   -  *``ssh://`` -* Fetches files from a secure shell.
+   -  *``svn://`` -* Fetches files from a Subversion (``svn``) revision
+      control repository.
+   -  *``npm://`` -* Fetches JavaScript modules from a registry.
+   Standard and recipe-specific options for ``SRC_URI`` exist. Here are
+   standard options:
+   -  *``apply`` -* Whether to apply the patch or not. The default
+      action is to apply the patch.
+   -  *``striplevel`` -* Which striplevel to use when applying the
+      patch. The default level is 1.
+   -  *``patchdir`` -* Specifies the directory in which the patch should
+      be applied. The default is ``${``\ ```S`` <#var-S>`__\ ``}``.
+   Here are options specific to recipes building code from a revision
+   control system:
+   -  *``mindate`` -* Apply the patch only if
+      ```SRCDATE`` <#var-SRCDATE>`__ is equal to or greater than
+      ``mindate``.
+   -  *``maxdate`` -* Apply the patch only if ``SRCDATE`` is not later
+      than ``maxdate``.
+   -  *``minrev`` -* Apply the patch only if ``SRCREV`` is equal to or
+      greater than ``minrev``.
+   -  *``maxrev`` -* Apply the patch only if ``SRCREV`` is not later
+      than ``maxrev``.
+   -  *``rev`` -* Apply the patch only if ``SRCREV`` is equal to
+      ``rev``.
+   -  *``notrev`` -* Apply the patch only if ``SRCREV`` is not equal to
+      ``rev``.
+   Here are some additional options worth mentioning:
+   -  *``unpack`` -* Controls whether or not to unpack the file if it is
+      an archive. The default action is to unpack the file.
+   -  *``destsuffix`` -* Places the file (or extracts its contents) into
+      the specified subdirectory of ```WORKDIR`` <#var-WORKDIR>`__ when
+      the Git fetcher is used.
+   -  *``subdir`` -* Places the file (or extracts its contents) into the
+      specified subdirectory of ``WORKDIR`` when the local (``file://``)
+      fetcher is used.
+   -  *``localdir`` -* Places the file (or extracts its contents) into
+      the specified subdirectory of ``WORKDIR`` when the CVS fetcher is
+      used.
+   -  *``subpath`` -* Limits the checkout to a specific subpath of the
+      tree when using the Git fetcher is used.
+   -  *``name`` -* Specifies a name to be used for association with
+      ``SRC_URI`` checksums when you have more than one file specified
+      in ``SRC_URI``.
+   -  *``downloadfilename`` -* Specifies the filename used when storing
+      the downloaded file.
+SRC_URI_OVERRIDES_PACKAGE_ARCH
+   By default, the OpenEmbedded build system automatically detects
+   whether ``SRC_URI`` contains files that are machine-specific. If so,
+   the build system automatically changes ``PACKAGE_ARCH``. Setting this
+   variable to "0" disables this behavior.
+SRCDATE
+   The date of the source code used to build the package. This variable
+   applies only if the source was fetched from a Source Code Manager
+   (SCM).
+SRCPV
+   Returns the version string of the current package. This string is
+   used to help define the value of ```PV`` <#var-PV>`__.
+   The ``SRCPV`` variable is defined in the ``meta/conf/bitbake.conf``
+   configuration file in the `Source Directory <#source-directory>`__ as
+   follows: SRCPV = "${@bb.fetch2.get_srcrev(d)}"
+   Recipes that need to define ``PV`` do so with the help of the
+   ``SRCPV``. For example, the ``ofono`` recipe (``ofono_git.bb``)
+   located in ``meta/recipes-connectivity`` in the Source Directory
+   defines ``PV`` as follows: PV = "0.12-git${SRCPV}"
+SRCREV
+   The revision of the source code used to build the package. This
+   variable applies to Subversion, Git, Mercurial, and Bazaar only. Note
+   that if you want to build a fixed revision and you want to avoid
+   performing a query on the remote repository every time BitBake parses
+   your recipe, you should specify a ``SRCREV`` that is a full revision
+   identifier and not just a tag.
+   .. note::
+      For information on limitations when inheriting the latest revision
+      of software using
+      SRCREV
+      , see the
+      AUTOREV
+      variable description and the "
+      Automatically Incrementing a Binary Package Revision Number
+      " section, which is in the Yocto Project Development Tasks Manual.
+SSTATE_DIR
+   The directory for the shared state cache.
+SSTATE_MIRROR_ALLOW_NETWORK
+   If set to "1", allows fetches from mirrors that are specified in
+   ```SSTATE_MIRRORS`` <#var-SSTATE_MIRRORS>`__ to work even when
+   fetching from the network is disabled by setting ``BB_NO_NETWORK`` to
+   "1". Using the ``SSTATE_MIRROR_ALLOW_NETWORK`` variable is useful if
+   you have set ``SSTATE_MIRRORS`` to point to an internal server for
+   your shared state cache, but you want to disable any other fetching
+   from the network.
+SSTATE_MIRRORS
+   Configures the OpenEmbedded build system to search other mirror
+   locations for prebuilt cache data objects before building out the
+   data. This variable works like fetcher ```MIRRORS`` <#var-MIRRORS>`__
+   and ```PREMIRRORS`` <#var-PREMIRRORS>`__ and points to the cache
+   locations to check for the shared state (sstate) objects.
+   You can specify a filesystem directory or a remote URL such as HTTP
+   or FTP. The locations you specify need to contain the shared state
+   cache (sstate-cache) results from previous builds. The sstate-cache
+   you point to can also be from builds on other machines.
+   When pointing to sstate build artifacts on another machine that uses
+   a different GCC version for native builds, you must configure
+   ``SSTATE_MIRRORS`` with a regular expression that maps local search
+   paths to server paths. The paths need to take into account
+   ```NATIVELSBSTRING`` <#var-NATIVELSBSTRING>`__ set by the
+   ```uninative`` <#ref-classes-uninative>`__ class. For example, the
+   following maps the local search path ``universal-4.9`` to the
+   server-provided path server_url_sstate_path: SSTATE_MIRRORS ?=
+   file://universal-4.9/(.*)
+   http://server_url_sstate_path/universal-4.8/\1 \\n
+   If a mirror uses the same structure as
+   ```SSTATE_DIR`` <#var-SSTATE_DIR>`__, you need to add "PATH" at the
+   end as shown in the examples below. The build system substitutes the
+   correct path within the directory structure. SSTATE_MIRRORS ?= "\\
+   file://.\*
+   http://someserver.tld/share/sstate/PATH;downloadfilename=PATH \\n \\
+   file://.\* file:///some-local-dir/sstate/PATH"
+SSTATE_SCAN_FILES
+   Controls the list of files the OpenEmbedded build system scans for
+   hardcoded installation paths. The variable uses a space-separated
+   list of filenames (not paths) with standard wildcard characters
+   allowed.
+   During a build, the OpenEmbedded build system creates a shared state
+   (sstate) object during the first stage of preparing the sysroots.
+   That object is scanned for hardcoded paths for original installation
+   locations. The list of files that are scanned for paths is controlled
+   by the ``SSTATE_SCAN_FILES`` variable. Typically, recipes add files
+   they want to be scanned to the value of ``SSTATE_SCAN_FILES`` rather
+   than the variable being comprehensively set. The
+   ```sstate`` <#ref-classes-sstate>`__ class specifies the default list
+   of files.
+   For details on the process, see the
+   ```staging`` <#ref-classes-staging>`__ class.
+STAGING_BASE_LIBDIR_NATIVE
+   Specifies the path to the ``/lib`` subdirectory of the sysroot
+   directory for the build host.
+STAGING_BASELIBDIR
+   Specifies the path to the ``/lib`` subdirectory of the sysroot
+   directory for the target for which the current recipe is being built
+   (```STAGING_DIR_HOST`` <#var-STAGING_DIR_HOST>`__).
+STAGING_BINDIR
+   Specifies the path to the ``/usr/bin`` subdirectory of the sysroot
+   directory for the target for which the current recipe is being built
+   (```STAGING_DIR_HOST`` <#var-STAGING_DIR_HOST>`__).
+STAGING_BINDIR_CROSS
+   Specifies the path to the directory containing binary configuration
+   scripts. These scripts provide configuration information for other
+   software that wants to make use of libraries or include files
+   provided by the software associated with the script.
+   .. note::
+      This style of build configuration has been largely replaced by
+      pkg-config
+      . Consequently, if
+      pkg-config
+      is supported by the library to which you are linking, it is
+      recommended you use
+      pkg-config
+      instead of a provided configuration script.
+STAGING_BINDIR_NATIVE
+   Specifies the path to the ``/usr/bin`` subdirectory of the sysroot
+   directory for the build host.
+STAGING_DATADIR
+   Specifies the path to the ``/usr/share`` subdirectory of the sysroot
+   directory for the target for which the current recipe is being built
+   (```STAGING_DIR_HOST`` <#var-STAGING_DIR_HOST>`__).
+STAGING_DATADIR_NATIVE
+   Specifies the path to the ``/usr/share`` subdirectory of the sysroot
+   directory for the build host.
+STAGING_DIR
+   Helps construct the ``recipe-sysroots`` directory, which is used
+   during packaging.
+   For information on how staging for recipe-specific sysroots occurs,
+   see the ```do_populate_sysroot`` <#ref-tasks-populate_sysroot>`__
+   task, the "`Sharing Files Between
+   Recipes <&YOCTO_DOCS_DEV_URL;#new-sharing-files-between-recipes>`__"
+   section in the Yocto Project Development Tasks Manual, the
+   "`Configuration, Compilation, and
+   Staging <&YOCTO_DOCS_OM_URL;#configuration-compilation-and-staging-dev-environment>`__"
+   section in the Yocto Project Overview and Concepts Manual, and the
+   ```SYSROOT_DIRS`` <#var-SYSROOT_DIRS>`__ variable.
+   .. note::
+      Recipes should never write files directly under the
+      STAGING_DIR
+      directory because the OpenEmbedded build system manages the
+      directory automatically. Instead, files should be installed to
+      ${
+      D
+      }
+      within your recipe's
+      do_install
+      task and then the OpenEmbedded build system will stage a subset of
+      those files into the sysroot.
+STAGING_DIR_HOST
+   Specifies the path to the sysroot directory for the system on which
+   the component is built to run (the system that hosts the component).
+   For most recipes, this sysroot is the one in which that recipe's
+   ```do_populate_sysroot`` <#ref-tasks-populate_sysroot>`__ task copies
+   files. Exceptions include ``-native`` recipes, where the
+   ``do_populate_sysroot`` task instead uses
+   ```STAGING_DIR_NATIVE`` <#var-STAGING_DIR_NATIVE>`__. Depending on
+   the type of recipe and the build target, ``STAGING_DIR_HOST`` can
+   have the following values:
+   -  For recipes building for the target machine, the value is
+      "${`STAGING_DIR <#var-STAGING_DIR>`__}/${`MACHINE <#var-MACHINE>`__}".
+   -  For native recipes building for the build host, the value is empty
+      given the assumption that when building for the build host, the
+      build host's own directories should be used.
+      .. note::
+         ``-native`` recipes are not installed into host paths like such
+         as ``/usr``. Rather, these recipes are installed into
+         ``STAGING_DIR_NATIVE``. When compiling ``-native`` recipes,
+         standard build environment variables such as
+         ```CPPFLAGS`` <#var-CPPFLAGS>`__ and
+         ```CFLAGS`` <#var-CFLAGS>`__ are set up so that both host paths
+         and ``STAGING_DIR_NATIVE`` are searched for libraries and
+         headers using, for example, GCC's ``-isystem`` option.
+         Thus, the emphasis is that the ``STAGING_DIR*`` variables
+         should be viewed as input variables by tasks such as
+         ```do_configure`` <#ref-tasks-configure>`__,
+         ```do_compile`` <#ref-tasks-compile>`__, and
+         ```do_install`` <#ref-tasks-install>`__. Having the real system
+         root correspond to ``STAGING_DIR_HOST`` makes conceptual sense
+         for ``-native`` recipes, as they make use of host headers and
+         libraries.
+STAGING_DIR_NATIVE
+   Specifies the path to the sysroot directory used when building
+   components that run on the build host itself.
+STAGING_DIR_TARGET
+   Specifies the path to the sysroot used for the system for which the
+   component generates code. For components that do not generate code,
+   which is the majority, ``STAGING_DIR_TARGET`` is set to match
+   ```STAGING_DIR_HOST`` <#var-STAGING_DIR_HOST>`__.
+   Some recipes build binaries that can run on the target system but
+   those binaries in turn generate code for another different system
+   (e.g. cross-canadian recipes). Using terminology from GNU, the
+   primary system is referred to as the "HOST" and the secondary, or
+   different, system is referred to as the "TARGET". Thus, the binaries
+   run on the "HOST" system and generate binaries for the "TARGET"
+   system. The ``STAGING_DIR_HOST`` variable points to the sysroot used
+   for the "HOST" system, while ``STAGING_DIR_TARGET`` points to the
+   sysroot used for the "TARGET" system.
+STAGING_ETCDIR_NATIVE
+   Specifies the path to the ``/etc`` subdirectory of the sysroot
+   directory for the build host.
+STAGING_EXECPREFIXDIR
+   Specifies the path to the ``/usr`` subdirectory of the sysroot
+   directory for the target for which the current recipe is being built
+   (```STAGING_DIR_HOST`` <#var-STAGING_DIR_HOST>`__).
+STAGING_INCDIR
+   Specifies the path to the ``/usr/include`` subdirectory of the
+   sysroot directory for the target for which the current recipe being
+   built (```STAGING_DIR_HOST`` <#var-STAGING_DIR_HOST>`__).
+STAGING_INCDIR_NATIVE
+   Specifies the path to the ``/usr/include`` subdirectory of the
+   sysroot directory for the build host.
+STAGING_KERNEL_BUILDDIR
+   Points to the directory containing the kernel build artifacts.
+   Recipes building software that needs to access kernel build artifacts
+   (e.g. ``systemtap-uprobes``) can look in the directory specified with
+   the ``STAGING_KERNEL_BUILDDIR`` variable to find these artifacts
+   after the kernel has been built.
+STAGING_KERNEL_DIR
+   The directory with kernel headers that are required to build
+   out-of-tree modules.
+STAGING_LIBDIR
+   Specifies the path to the ``/usr/lib`` subdirectory of the sysroot
+   directory for the target for which the current recipe is being built
+   (```STAGING_DIR_HOST`` <#var-STAGING_DIR_HOST>`__).
+STAGING_LIBDIR_NATIVE
+   Specifies the path to the ``/usr/lib`` subdirectory of the sysroot
+   directory for the build host.
+STAMP
+   Specifies the base path used to create recipe stamp files. The path
+   to an actual stamp file is constructed by evaluating this string and
+   then appending additional information. Currently, the default
+   assignment for ``STAMP`` as set in the ``meta/conf/bitbake.conf``
+   file is: STAMP =
+   "${STAMPS_DIR}/${MULTIMACH_TARGET_SYS}/${PN}/${EXTENDPE}${PV}-${PR}"
+   For information on how BitBake uses stamp files to determine if a
+   task should be rerun, see the "`Stamp Files and the Rerunning of
+   Tasks <&YOCTO_DOCS_OM_URL;#stamp-files-and-the-rerunning-of-tasks>`__"
+   section in the Yocto Project Overview and Concepts Manual.
+   See ```STAMPS_DIR`` <#var-STAMPS_DIR>`__,
+   ```MULTIMACH_TARGET_SYS`` <#var-MULTIMACH_TARGET_SYS>`__,
+   ```PN`` <#var-PN>`__, ```EXTENDPE`` <#var-EXTENDPE>`__,
+   ```PV`` <#var-PV>`__, and ```PR`` <#var-PR>`__ for related variable
+   information.
+STAMPS_DIR
+   Specifies the base directory in which the OpenEmbedded build system
+   places stamps. The default directory is ``${TMPDIR}/stamps``.
+STRIP
+   The minimal command and arguments to run ``strip``, which is used to
+   strip symbols.
+SUMMARY
+   The short (72 characters or less) summary of the binary package for
+   packaging systems such as ``opkg``, ``rpm``, or ``dpkg``. By default,
+   ``SUMMARY`` is used to define the
+   ```DESCRIPTION`` <#var-DESCRIPTION>`__ variable if ``DESCRIPTION`` is
+   not set in the recipe.
+SVNDIR
+   The directory in which files checked out of a Subversion system are
+   stored.
+SYSLINUX_DEFAULT_CONSOLE
+   Specifies the kernel boot default console. If you want to use a
+   console other than the default, set this variable in your recipe as
+   follows where "X" is the console number you want to use:
+   SYSLINUX_DEFAULT_CONSOLE = "console=ttyX"
+   The ```syslinux`` <#ref-classes-syslinux>`__ class initially sets
+   this variable to null but then checks for a value later.
+SYSLINUX_OPTS
+   Lists additional options to add to the syslinux file. You need to set
+   this variable in your recipe. If you want to list multiple options,
+   separate the options with a semicolon character (``;``).
+   The ```syslinux`` <#ref-classes-syslinux>`__ class uses this variable
+   to create a set of options.
+SYSLINUX_SERIAL
+   Specifies the alternate serial port or turns it off. To turn off
+   serial, set this variable to an empty string in your recipe. The
+   variable's default value is set in the
+   ```syslinux`` <#ref-classes-syslinux>`__ class as follows:
+   SYSLINUX_SERIAL ?= "0 115200"
+   The class checks for and uses the variable as needed.
+SYSLINUX_SPLASH
+   An ``.LSS`` file used as the background for the VGA boot menu when
+   you use the boot menu. You need to set this variable in your recipe.
+   The ```syslinux`` <#ref-classes-syslinux>`__ class checks for this
+   variable and if found, the OpenEmbedded build system installs the
+   splash screen.
+SYSLINUX_SERIAL_TTY
+   Specifies the alternate console=tty... kernel boot argument. The
+   variable's default value is set in the
+   ```syslinux`` <#ref-classes-syslinux>`__ class as follows:
+   SYSLINUX_SERIAL_TTY ?= "console=ttyS0,115200"
+   The class checks for and uses the variable as needed.
+SYSROOT_DESTDIR
+   Points to the temporary directory under the work directory (default
+   "``${``\ ```WORKDIR`` <#var-WORKDIR>`__\ ``}/sysroot-destdir``")
+   where the files populated into the sysroot are assembled during the
+   ```do_populate_sysroot`` <#ref-tasks-populate_sysroot>`__ task.
+SYSROOT_DIRS
+   Directories that are staged into the sysroot by the
+   ```do_populate_sysroot`` <#ref-tasks-populate_sysroot>`__ task. By
+   default, the following directories are staged: SYSROOT_DIRS = " \\
+   ${includedir} \\ ${libdir} \\ ${base_libdir} \\
+   ${nonarch_base_libdir} \\ ${datadir} \\ "
+SYSROOT_DIRS_BLACKLIST
+   Directories that are not staged into the sysroot by the
+   ```do_populate_sysroot`` <#ref-tasks-populate_sysroot>`__ task. You
+   can use this variable to exclude certain subdirectories of
+   directories listed in ```SYSROOT_DIRS`` <#var-SYSROOT_DIRS>`__ from
+   staging. By default, the following directories are not staged:
+   SYSROOT_DIRS_BLACKLIST = " \\ ${mandir} \\ ${docdir} \\ ${infodir} \\
+   ${datadir}/locale \\ ${datadir}/applications \\ ${datadir}/fonts \\
+   ${datadir}/pixmaps \\ "
+SYSROOT_DIRS_NATIVE
+   Extra directories staged into the sysroot by the
+   ```do_populate_sysroot`` <#ref-tasks-populate_sysroot>`__ task for
+   ``-native`` recipes, in addition to those specified in
+   ```SYSROOT_DIRS`` <#var-SYSROOT_DIRS>`__. By default, the following
+   extra directories are staged: SYSROOT_DIRS_NATIVE = " \\ ${bindir} \\
+   ${sbindir} \\ ${base_bindir} \\ ${base_sbindir} \\ ${libexecdir} \\
+   ${sysconfdir} \\ ${localstatedir} \\ "
+   .. note::
+      Programs built by
+      -native
+      recipes run directly from the sysroot (
+      STAGING_DIR_NATIVE
+      ), which is why additional directories containing program
+      executables and supporting files need to be staged.
+SYSROOT_PREPROCESS_FUNCS
+   A list of functions to execute after files are staged into the
+   sysroot. These functions are usually used to apply additional
+   processing on the staged files, or to stage additional files.
+SYSTEMD_AUTO_ENABLE
+   When inheriting the ```systemd`` <#ref-classes-systemd>`__ class,
+   this variable specifies whether the specified service in
+   ```SYSTEMD_SERVICE`` <#var-SYSTEMD_SERVICE>`__ should start
+   automatically or not. By default, the service is enabled to
+   automatically start at boot time. The default setting is in the
+   ```systemd`` <#ref-classes-systemd>`__ class as follows:
+   SYSTEMD_AUTO_ENABLE ??= "enable"
+   You can disable the service by setting the variable to "disable".
+SYSTEMD_BOOT_CFG
+   When ```EFI_PROVIDER`` <#var-EFI_PROVIDER>`__ is set to
+   "systemd-boot", the ``SYSTEMD_BOOT_CFG`` variable specifies the
+   configuration file that should be used. By default, the
+   ```systemd-boot`` <#ref-classes-systemd-boot>`__ class sets the
+   ``SYSTEMD_BOOT_CFG`` as follows: SYSTEMD_BOOT_CFG ?=
+   "${`S <#var-S>`__}/loader.conf"
+   For information on Systemd-boot, see the `Systemd-boot
+   documentation <http://www.freedesktop.org/wiki/Software/systemd/systemd-boot/>`__.
+SYSTEMD_BOOT_ENTRIES
+   When ```EFI_PROVIDER`` <#var-EFI_PROVIDER>`__ is set to
+   "systemd-boot", the ``SYSTEMD_BOOT_ENTRIES`` variable specifies a
+   list of entry files (``*.conf``) to install that contain one boot
+   entry per file. By default, the
+   ```systemd-boot`` <#ref-classes-systemd-boot>`__ class sets the
+   ``SYSTEMD_BOOT_ENTRIES`` as follows: SYSTEMD_BOOT_ENTRIES ?= ""
+   For information on Systemd-boot, see the `Systemd-boot
+   documentation <http://www.freedesktop.org/wiki/Software/systemd/systemd-boot/>`__.
+SYSTEMD_BOOT_TIMEOUT
+   When ```EFI_PROVIDER`` <#var-EFI_PROVIDER>`__ is set to
+   "systemd-boot", the ``SYSTEMD_BOOT_TIMEOUT`` variable specifies the
+   boot menu timeout in seconds. By default, the
+   ```systemd-boot`` <#ref-classes-systemd-boot>`__ class sets the
+   ``SYSTEMD_BOOT_TIMEOUT`` as follows: SYSTEMD_BOOT_TIMEOUT ?= "10"
+   For information on Systemd-boot, see the `Systemd-boot
+   documentation <http://www.freedesktop.org/wiki/Software/systemd/systemd-boot/>`__.
+SYSTEMD_PACKAGES
+   When inheriting the ```systemd`` <#ref-classes-systemd>`__ class,
+   this variable locates the systemd unit files when they are not found
+   in the main recipe's package. By default, the ``SYSTEMD_PACKAGES``
+   variable is set such that the systemd unit files are assumed to
+   reside in the recipes main package: SYSTEMD_PACKAGES ?= "${PN}"
+   If these unit files are not in this recipe's main package, you need
+   to use ``SYSTEMD_PACKAGES`` to list the package or packages in which
+   the build system can find the systemd unit files.
+SYSTEMD_SERVICE
+   When inheriting the ```systemd`` <#ref-classes-systemd>`__ class,
+   this variable specifies the systemd service name for a package.
+   When you specify this file in your recipe, use a package name
+   override to indicate the package to which the value applies. Here is
+   an example from the connman recipe: SYSTEMD_SERVICE_${PN} =
+   "connman.service"
+SYSVINIT_ENABLED_GETTYS
+   When using
+   `SysVinit <&YOCTO_DOCS_DEV_URL;#new-recipe-enabling-system-services>`__,
+   specifies a space-separated list of the virtual terminals that should
+   run a `getty <http://en.wikipedia.org/wiki/Getty_%28Unix%29>`__
+   (allowing login), assuming ```USE_VT`` <#var-USE_VT>`__ is not set to
+   "0".
+   The default value for ``SYSVINIT_ENABLED_GETTYS`` is "1" (i.e. only
+   run a getty on the first virtual terminal).
+T
+   This variable points to a directory were BitBake places temporary
+   files, which consist mostly of task logs and scripts, when building a
+   particular recipe. The variable is typically set as follows: T =
+   "${WORKDIR}/temp"
+   The ```WORKDIR`` <#var-WORKDIR>`__ is the directory into which
+   BitBake unpacks and builds the recipe. The default ``bitbake.conf``
+   file sets this variable.
+   The ``T`` variable is not to be confused with the
+   ```TMPDIR`` <#var-TMPDIR>`__ variable, which points to the root of
+   the directory tree where BitBake places the output of an entire
+   build.
+TARGET_ARCH
+   The target machine's architecture. The OpenEmbedded build system
+   supports many architectures. Here is an example list of architectures
+   supported. This list is by no means complete as the architecture is
+   configurable: arm i586 x86_64 powerpc powerpc64 mips mipsel
+   For additional information on machine architectures, see the
+   ```TUNE_ARCH`` <#var-TUNE_ARCH>`__ variable.
+TARGET_AS_ARCH
+   Specifies architecture-specific assembler flags for the target
+   system. ``TARGET_AS_ARCH`` is initialized from
+   ```TUNE_ASARGS`` <#var-TUNE_ASARGS>`__ by default in the BitBake
+   configuration file (``meta/conf/bitbake.conf``): TARGET_AS_ARCH =
+   "${TUNE_ASARGS}"
+TARGET_CC_ARCH
+   Specifies architecture-specific C compiler flags for the target
+   system. ``TARGET_CC_ARCH`` is initialized from
+   ```TUNE_CCARGS`` <#var-TUNE_CCARGS>`__ by default.
+   .. note::
+      It is a common workaround to append
+      LDFLAGS
+      to
+      TARGET_CC_ARCH
+      in recipes that build software for the target that would not
+      otherwise respect the exported
+      LDFLAGS
+      variable.
+TARGET_CC_KERNEL_ARCH
+   This is a specific kernel compiler flag for a CPU or Application
+   Binary Interface (ABI) tune. The flag is used rarely and only for
+   cases where a userspace ```TUNE_CCARGS`` <#var-TUNE_CCARGS>`__ is not
+   compatible with the kernel compilation. The ``TARGET_CC_KERNEL_ARCH``
+   variable allows the kernel (and associated modules) to use a
+   different configuration. See the
+   ``meta/conf/machine/include/arm/feature-arm-thumb.inc`` file in the
+   `Source Directory <#source-directory>`__ for an example.
+TARGET_CFLAGS
+   Specifies the flags to pass to the C compiler when building for the
+   target. When building in the target context,
+   ```CFLAGS`` <#var-CFLAGS>`__ is set to the value of this variable by
+   default.
+   Additionally, the SDK's environment setup script sets the ``CFLAGS``
+   variable in the environment to the ``TARGET_CFLAGS`` value so that
+   executables built using the SDK also have the flags applied.
+TARGET_CPPFLAGS
+   Specifies the flags to pass to the C pre-processor (i.e. to both the
+   C and the C++ compilers) when building for the target. When building
+   in the target context, ```CPPFLAGS`` <#var-CPPFLAGS>`__ is set to the
+   value of this variable by default.
+   Additionally, the SDK's environment setup script sets the
+   ``CPPFLAGS`` variable in the environment to the ``TARGET_CPPFLAGS``
+   value so that executables built using the SDK also have the flags
+   applied.
+TARGET_CXXFLAGS
+   Specifies the flags to pass to the C++ compiler when building for the
+   target. When building in the target context,
+   ```CXXFLAGS`` <#var-CXXFLAGS>`__ is set to the value of this variable
+   by default.
+   Additionally, the SDK's environment setup script sets the
+   ``CXXFLAGS`` variable in the environment to the ``TARGET_CXXFLAGS``
+   value so that executables built using the SDK also have the flags
+   applied.
+TARGET_FPU
+   Specifies the method for handling FPU code. For FPU-less targets,
+   which include most ARM CPUs, the variable must be set to "soft". If
+   not, the kernel emulation gets used, which results in a performance
+   penalty.
+TARGET_LD_ARCH
+   Specifies architecture-specific linker flags for the target system.
+   ``TARGET_LD_ARCH`` is initialized from
+   ```TUNE_LDARGS`` <#var-TUNE_LDARGS>`__ by default in the BitBake
+   configuration file (``meta/conf/bitbake.conf``): TARGET_LD_ARCH =
+   "${TUNE_LDARGS}"
+TARGET_LDFLAGS
+   Specifies the flags to pass to the linker when building for the
+   target. When building in the target context,
+   ```LDFLAGS`` <#var-LDFLAGS>`__ is set to the value of this variable
+   by default.
+   Additionally, the SDK's environment setup script sets the
+   ```LDFLAGS`` <#var-LDFLAGS>`__ variable in the environment to the
+   ``TARGET_LDFLAGS`` value so that executables built using the SDK also
+   have the flags applied.
+TARGET_OS
+   Specifies the target's operating system. The variable can be set to
+   "linux" for glibc-based systems (GNU C Library) and to "linux-musl"
+   for musl libc. For ARM/EABI targets, "linux-gnueabi" and
+   "linux-musleabi" possible values exist.
+TARGET_PREFIX
+   Specifies the prefix used for the toolchain binary target tools.
+   Depending on the type of recipe and the build target,
+   ``TARGET_PREFIX`` is set as follows:
+   -  For recipes building for the target machine, the value is
+      "${`TARGET_SYS <#var-TARGET_SYS>`__}-".
+   -  For native recipes, the build system sets the variable to the
+      value of ``BUILD_PREFIX``.
+   -  For native SDK recipes (``nativesdk``), the build system sets the
+      variable to the value of ``SDK_PREFIX``.
+TARGET_SYS
+   Specifies the system, including the architecture and the operating
+   system, for which the build is occurring in the context of the
+   current recipe.
+   The OpenEmbedded build system automatically sets this variable based
+   on ```TARGET_ARCH`` <#var-TARGET_ARCH>`__,
+   ```TARGET_VENDOR`` <#var-TARGET_VENDOR>`__, and
+   ```TARGET_OS`` <#var-TARGET_OS>`__ variables.
+   .. note::
+      You do not need to set the
+      TARGET_SYS
+      variable yourself.
+   Consider these two examples:
+   -  Given a native recipe on a 32-bit, x86 machine running Linux, the
+      value is "i686-linux".
+   -  Given a recipe being built for a little-endian, MIPS target
+      running Linux, the value might be "mipsel-linux".
+TARGET_VENDOR
+   Specifies the name of the target vendor.
+TCLIBC
+   Specifies the GNU standard C library (``libc``) variant to use during
+   the build process. This variable replaces ``POKYLIBC``, which is no
+   longer supported.
+   You can select "glibc", "musl", "newlib", or "baremetal"
+TCLIBCAPPEND
+   Specifies a suffix to be appended onto the
+   ```TMPDIR`` <#var-TMPDIR>`__ value. The suffix identifies the
+   ``libc`` variant for building. When you are building for multiple
+   variants with the same `Build Directory <#build-directory>`__, this
+   mechanism ensures that output for different ``libc`` variants is kept
+   separate to avoid potential conflicts.
+   In the ``defaultsetup.conf`` file, the default value of
+   ``TCLIBCAPPEND`` is "-${TCLIBC}". However, distros such as poky,
+   which normally only support one ``libc`` variant, set
+   ``TCLIBCAPPEND`` to "" in their distro configuration file resulting
+   in no suffix being applied.
+TCMODE
+   Specifies the toolchain selector. ``TCMODE`` controls the
+   characteristics of the generated packages and images by telling the
+   OpenEmbedded build system which toolchain profile to use. By default,
+   the OpenEmbedded build system builds its own internal toolchain. The
+   variable's default value is "default", which uses that internal
+   toolchain.
+   .. note::
+      If
+      TCMODE
+      is set to a value other than "default", then it is your
+      responsibility to ensure that the toolchain is compatible with the
+      default toolchain. Using older or newer versions of these
+      components might cause build problems. See the Release Notes for
+      the Yocto Project release for the specific components with which
+      the toolchain must be compatible. To access the Release Notes, go
+      to the
+      Downloads
+      page on the Yocto Project website and click on the "RELEASE
+      INFORMATION" link for the appropriate release.
+   The ``TCMODE`` variable is similar to ```TCLIBC`` <#var-TCLIBC>`__,
+   which controls the variant of the GNU standard C library (``libc``)
+   used during the build process: ``glibc`` or ``musl``.
+   With additional layers, it is possible to use a pre-compiled external
+   toolchain. One example is the Sourcery G++ Toolchain. The support for
+   this toolchain resides in the separate Mentor Graphics
+   ``meta-sourcery`` layer at
+   ` <http://github.com/MentorEmbedded/meta-sourcery/>`__.
+   The layer's ``README`` file contains information on how to use the
+   Sourcery G++ Toolchain as an external toolchain. In summary, you must
+   be sure to add the layer to your ``bblayers.conf`` file in front of
+   the ``meta`` layer and then set the ``EXTERNAL_TOOLCHAIN`` variable
+   in your ``local.conf`` file to the location in which you installed
+   the toolchain.
+   The fundamentals used for this example apply to any external
+   toolchain. You can use ``meta-sourcery`` as a template for adding
+   support for other external toolchains.
+TEST_EXPORT_DIR
+   The location the OpenEmbedded build system uses to export tests when
+   the ```TEST_EXPORT_ONLY`` <#var-TEST_EXPORT_ONLY>`__ variable is set
+   to "1".
+   The ``TEST_EXPORT_DIR`` variable defaults to
+   ``"${TMPDIR}/testimage/${PN}"``.
+TEST_EXPORT_ONLY
+   Specifies to export the tests only. Set this variable to "1" if you
+   do not want to run the tests but you want them to be exported in a
+   manner that you to run them outside of the build system.
+TEST_LOG_DIR
+   Holds the SSH log and the boot log for QEMU machines. The
+   ``TEST_LOG_DIR`` variable defaults to ``"${WORKDIR}/testimage"``.
+   .. note::
+      Actual test results reside in the task log (
+      log.do_testimage
+      ), which is in the
+      ${WORKDIR}/temp/
+      directory.
+TEST_POWERCONTROL_CMD
+   For automated hardware testing, specifies the command to use to
+   control the power of the target machine under test. Typically, this
+   command would point to a script that performs the appropriate action
+   (e.g. interacting with a web-enabled power strip). The specified
+   command should expect to receive as the last argument "off", "on" or
+   "cycle" specifying to power off, on, or cycle (power off and then
+   power on) the device, respectively.
+TEST_POWERCONTROL_EXTRA_ARGS
+   For automated hardware testing, specifies additional arguments to
+   pass through to the command specified in
+   ```TEST_POWERCONTROL_CMD`` <#var-TEST_POWERCONTROL_CMD>`__. Setting
+   ``TEST_POWERCONTROL_EXTRA_ARGS`` is optional. You can use it if you
+   wish, for example, to separate the machine-specific and
+   non-machine-specific parts of the arguments.
+TEST_QEMUBOOT_TIMEOUT
+   The time in seconds allowed for an image to boot before automated
+   runtime tests begin to run against an image. The default timeout
+   period to allow the boot process to reach the login prompt is 500
+   seconds. You can specify a different value in the ``local.conf``
+   file.
+   For more information on testing images, see the "`Performing
+   Automated Runtime
+   Testing <&YOCTO_DOCS_DEV_URL;#performing-automated-runtime-testing>`__"
+   section in the Yocto Project Development Tasks Manual.
+TEST_SERIALCONTROL_CMD
+   For automated hardware testing, specifies the command to use to
+   connect to the serial console of the target machine under test. This
+   command simply needs to connect to the serial console and forward
+   that connection to standard input and output as any normal terminal
+   program does.
+   For example, to use the Picocom terminal program on serial device
+   ``/dev/ttyUSB0`` at 115200bps, you would set the variable as follows:
+   TEST_SERIALCONTROL_CMD = "picocom /dev/ttyUSB0 -b 115200"
+TEST_SERIALCONTROL_EXTRA_ARGS
+   For automated hardware testing, specifies additional arguments to
+   pass through to the command specified in
+   ```TEST_SERIALCONTROL_CMD`` <#var-TEST_SERIALCONTROL_CMD>`__. Setting
+   ``TEST_SERIALCONTROL_EXTRA_ARGS`` is optional. You can use it if you
+   wish, for example, to separate the machine-specific and
+   non-machine-specific parts of the command.
+TEST_SERVER_IP
+   The IP address of the build machine (host machine). This IP address
+   is usually automatically detected. However, if detection fails, this
+   variable needs to be set to the IP address of the build machine (i.e.
+   where the build is taking place).
+   .. note::
+      The
+      TEST_SERVER_IP
+      variable is only used for a small number of tests such as the
+      "dnf" test suite, which needs to download packages from
+      WORKDIR/oe-rootfs-repo
+      .
+TEST_TARGET
+   Specifies the target controller to use when running tests against a
+   test image. The default controller to use is "qemu": TEST_TARGET =
+   "qemu"
+   A target controller is a class that defines how an image gets
+   deployed on a target and how a target is started. A layer can extend
+   the controllers by adding a module in the layer's
+   ``/lib/oeqa/controllers`` directory and by inheriting the
+   ``BaseTarget`` class, which is an abstract class that cannot be used
+   as a value of ``TEST_TARGET``.
+   You can provide the following arguments with ``TEST_TARGET``:
+   -  *"qemu":* Boots a QEMU image and runs the tests. See the
+      "`Enabling Runtime Tests on
+      QEMU <&YOCTO_DOCS_DEV_URL;#qemu-image-enabling-tests>`__" section
+      in the Yocto Project Development Tasks Manual for more
+      information.
+   -  *"simpleremote":* Runs the tests on target hardware that is
+      already up and running. The hardware can be on the network or it
+      can be a device running an image on QEMU. You must also set
+      ```TEST_TARGET_IP`` <#var-TEST_TARGET_IP>`__ when you use
+      "simpleremote".
+      .. note::
+         This argument is defined in
+         meta/lib/oeqa/controllers/simpleremote.py
+         .
+   For information on running tests on hardware, see the "`Enabling
+   Runtime Tests on
+   Hardware <&YOCTO_DOCS_DEV_URL;#hardware-image-enabling-tests>`__"
+   section in the Yocto Project Development Tasks Manual.
+TEST_TARGET_IP
+   The IP address of your hardware under test. The ``TEST_TARGET_IP``
+   variable has no effect when ```TEST_TARGET`` <#var-TEST_TARGET>`__ is
+   set to "qemu".
+   When you specify the IP address, you can also include a port. Here is
+   an example: TEST_TARGET_IP = "192.168.1.4:2201" Specifying a port is
+   useful when SSH is started on a non-standard port or in cases when
+   your hardware under test is behind a firewall or network that is not
+   directly accessible from your host and you need to do port address
+   translation.
+TEST_SUITES
+   An ordered list of tests (modules) to run against an image when
+   performing automated runtime testing.
+   The OpenEmbedded build system provides a core set of tests that can
+   be used against images.
+   .. note::
+      Currently, there is only support for running these tests under
+      QEMU.
+   Tests include ``ping``, ``ssh``, ``df`` among others. You can add
+   your own tests to the list of tests by appending ``TEST_SUITES`` as
+   follows: TEST_SUITES_append = " mytest" Alternatively, you can
+   provide the "auto" option to have all applicable tests run against
+   the image. TEST_SUITES_append = " auto" Using this option causes the
+   build system to automatically run tests that are applicable to the
+   image. Tests that are not applicable are skipped.
+   The order in which tests are run is important. Tests that depend on
+   another test must appear later in the list than the test on which
+   they depend. For example, if you append the list of tests with two
+   tests (``test_A`` and ``test_B``) where ``test_B`` is dependent on
+   ``test_A``, then you must order the tests as follows: TEST_SUITES = "
+   test_A test_B"
+   For more information on testing images, see the "`Performing
+   Automated Runtime
+   Testing <&YOCTO_DOCS_DEV_URL;#performing-automated-runtime-testing>`__"
+   section in the Yocto Project Development Tasks Manual.
+TESTIMAGE_AUTO
+   Automatically runs the series of automated tests for images when an
+   image is successfully built. Setting ``TESTIMAGE_AUTO`` to "1" causes
+   any image that successfully builds to automatically boot under QEMU.
+   Using the variable also adds in dependencies so that any SDK for
+   which testing is requested is automatically built first.
+   These tests are written in Python making use of the ``unittest``
+   module, and the majority of them run commands on the target system
+   over ``ssh``. You can set this variable to "1" in your ``local.conf``
+   file in the `Build Directory <#build-directory>`__ to have the
+   OpenEmbedded build system automatically run these tests after an
+   image successfully builds: TESTIMAGE_AUTO = "1" For more information
+   on enabling, running, and writing these tests, see the "`Performing
+   Automated Runtime
+   Testing <&YOCTO_DOCS_DEV_URL;#performing-automated-runtime-testing>`__"
+   section in the Yocto Project Development Tasks Manual and the
+   "```testimage*.bbclass`` <#ref-classes-testimage*>`__" section.
+THISDIR
+   The directory in which the file BitBake is currently parsing is
+   located. Do not manually set this variable.
+TIME
+   The time the build was started. Times appear using the hour, minute,
+   and second (HMS) format (e.g. "140159" for one minute and fifty-nine
+   seconds past 1400 hours).
+TMPDIR
+   This variable is the base directory the OpenEmbedded build system
+   uses for all build output and intermediate files (other than the
+   shared state cache). By default, the ``TMPDIR`` variable points to
+   ``tmp`` within the `Build Directory <#build-directory>`__.
+   If you want to establish this directory in a location other than the
+   default, you can uncomment and edit the following statement in the
+   ``conf/local.conf`` file in the `Source
+   Directory <#source-directory>`__: #TMPDIR = "${TOPDIR}/tmp" An
+   example use for this scenario is to set ``TMPDIR`` to a local disk,
+   which does not use NFS, while having the Build Directory use NFS.
+   The filesystem used by ``TMPDIR`` must have standard filesystem
+   semantics (i.e. mixed-case files are unique, POSIX file locking, and
+   persistent inodes). Due to various issues with NFS and bugs in some
+   implementations, NFS does not meet this minimum requirement.
+   Consequently, ``TMPDIR`` cannot be on NFS.
+TOOLCHAIN_HOST_TASK
+   This variable lists packages the OpenEmbedded build system uses when
+   building an SDK, which contains a cross-development environment. The
+   packages specified by this variable are part of the toolchain set
+   that runs on the ```SDKMACHINE`` <#var-SDKMACHINE>`__, and each
+   package should usually have the prefix ``nativesdk-``. For example,
+   consider the following command when building an SDK: $ bitbake -c
+   populate_sdk imagename In this case, a default list of packages is
+   set in this variable, but you can add additional packages to the
+   list. See the "`Adding Individual Packages to the Standard
+   SDK <&YOCTO_DOCS_SDK_URL;#sdk-adding-individual-packages>`__" section
+   in the Yocto Project Application Development and the Extensible
+   Software Development Kit (eSDK) manual for more information.
+   For background information on cross-development toolchains in the
+   Yocto Project development environment, see the "`Cross-Development
+   Toolchain
+   Generation <&YOCTO_DOCS_OM_URL;#cross-development-toolchain-generation>`__"
+   section in the Yocto Project Overview and Concepts Manual. For
+   information on setting up a cross-development environment, see the
+   `Yocto Project Application Development and the Extensible Software
+   Development Kit (eSDK) <&YOCTO_DOCS_SDK_URL;>`__ manual.
+TOOLCHAIN_OUTPUTNAME
+   This variable defines the name used for the toolchain output. The
+   ```populate_sdk_base`` <#ref-classes-populate-sdk-*>`__ class sets
+   the ``TOOLCHAIN_OUTPUTNAME`` variable as follows:
+   TOOLCHAIN_OUTPUTNAME ?= "${SDK_NAME}-toolchain-${SDK_VERSION}" See
+   the ```SDK_NAME`` <#var-SDK_NAME>`__ and
+   ```SDK_VERSION`` <#var-SDK_VERSION>`__ variables for additional
+   information.
+TOOLCHAIN_TARGET_TASK
+   This variable lists packages the OpenEmbedded build system uses when
+   it creates the target part of an SDK (i.e. the part built for the
+   target hardware), which includes libraries and headers. Use this
+   variable to add individual packages to the part of the SDK that runs
+   on the target. See the "`Adding Individual Packages to the Standard
+   SDK <&YOCTO_DOCS_SDK_URL;#sdk-adding-individual-packages>`__" section
+   in the Yocto Project Application Development and the Extensible
+   Software Development Kit (eSDK) manual for more information.
+   For background information on cross-development toolchains in the
+   Yocto Project development environment, see the "`Cross-Development
+   Toolchain
+   Generation <&YOCTO_DOCS_OM_URL;#cross-development-toolchain-generation>`__"
+   section in the Yocto Project Overview and Concepts Manual. For
+   information on setting up a cross-development environment, see the
+   `Yocto Project Application Development and the Extensible Software
+   Development Kit (eSDK) <&YOCTO_DOCS_SDK_URL;>`__ manual.
+TOPDIR
+   The top-level `Build Directory <#build-directory>`__. BitBake
+   automatically sets this variable when you initialize your build
+   environment using ````` <#structure-core-script>`__.
+TRANSLATED_TARGET_ARCH
+   A sanitized version of ```TARGET_ARCH`` <#var-TARGET_ARCH>`__. This
+   variable is used where the architecture is needed in a value where
+   underscores are not allowed, for example within package filenames. In
+   this case, dash characters replace any underscore characters used in
+   ``TARGET_ARCH``.
+   Do not edit this variable.
+TUNE_ARCH
+   The GNU canonical architecture for a specific architecture (i.e.
+   ``arm``, ``armeb``, ``mips``, ``mips64``, and so forth). BitBake uses
+   this value to setup configuration.
+   ``TUNE_ARCH`` definitions are specific to a given architecture. The
+   definitions can be a single static definition, or can be dynamically
+   adjusted. You can see details for a given CPU family by looking at
+   the architecture's ``README`` file. For example, the
+   ``meta/conf/machine/include/mips/README`` file in the `Source
+   Directory <#source-directory>`__ provides information for
+   ``TUNE_ARCH`` specific to the ``mips`` architecture.
+   ``TUNE_ARCH`` is tied closely to
+   ```TARGET_ARCH`` <#var-TARGET_ARCH>`__, which defines the target
+   machine's architecture. The BitBake configuration file
+   (``meta/conf/bitbake.conf``) sets ``TARGET_ARCH`` as follows:
+   TARGET_ARCH = "${TUNE_ARCH}"
+   The following list, which is by no means complete since architectures
+   are configurable, shows supported machine architectures: arm i586
+   x86_64 powerpc powerpc64 mips mipsel
+TUNE_ASARGS
+   Specifies architecture-specific assembler flags for the target
+   system. The set of flags is based on the selected tune features.
+   ``TUNE_ASARGS`` is set using the tune include files, which are
+   typically under ``meta/conf/machine/include/`` and are influenced
+   through ```TUNE_FEATURES`` <#var-TUNE_FEATURES>`__. For example, the
+   ``meta/conf/machine/include/x86/arch-x86.inc`` file defines the flags
+   for the x86 architecture as follows: TUNE_ASARGS +=
+   "${@bb.utils.contains("TUNE_FEATURES", "mx32", "-x32", "", d)}"
+   .. note::
+      Board Support Packages (BSPs) select the tune. The selected tune,
+      in turn, affects the tune variables themselves (i.e. the tune can
+      supply its own set of flags).
+TUNE_CCARGS
+   Specifies architecture-specific C compiler flags for the target
+   system. The set of flags is based on the selected tune features.
+   ``TUNE_CCARGS`` is set using the tune include files, which are
+   typically under ``meta/conf/machine/include/`` and are influenced
+   through ```TUNE_FEATURES`` <#var-TUNE_FEATURES>`__.
+   .. note::
+      Board Support Packages (BSPs) select the tune. The selected tune,
+      in turn, affects the tune variables themselves (i.e. the tune can
+      supply its own set of flags).
+TUNE_LDARGS
+   Specifies architecture-specific linker flags for the target system.
+   The set of flags is based on the selected tune features.
+   ``TUNE_LDARGS`` is set using the tune include files, which are
+   typically under ``meta/conf/machine/include/`` and are influenced
+   through ```TUNE_FEATURES`` <#var-TUNE_FEATURES>`__. For example, the
+   ``meta/conf/machine/include/x86/arch-x86.inc`` file defines the flags
+   for the x86 architecture as follows: TUNE_LDARGS +=
+   "${@bb.utils.contains("TUNE_FEATURES", "mx32", "-m elf32_x86_64", "",
+   d)}"
+   .. note::
+      Board Support Packages (BSPs) select the tune. The selected tune,
+      in turn, affects the tune variables themselves (i.e. the tune can
+      supply its own set of flags).
+TUNE_FEATURES
+   Features used to "tune" a compiler for optimal use given a specific
+   processor. The features are defined within the tune files and allow
+   arguments (i.e. ``TUNE_*ARGS``) to be dynamically generated based on
+   the features.
+   The OpenEmbedded build system verifies the features to be sure they
+   are not conflicting and that they are supported.
+   The BitBake configuration file (``meta/conf/bitbake.conf``) defines
+   ``TUNE_FEATURES`` as follows: TUNE_FEATURES ??=
+   "${TUNE_FEATURES_tune-${DEFAULTTUNE}}" See the
+   ```DEFAULTTUNE`` <#var-DEFAULTTUNE>`__ variable for more information.
+TUNE_PKGARCH
+   The package architecture understood by the packaging system to define
+   the architecture, ABI, and tuning of output packages. The specific
+   tune is defined using the "_tune" override as follows:
+   TUNE_PKGARCH_tune-tune = "tune"
+   These tune-specific package architectures are defined in the machine
+   include files. Here is an example of the "core2-32" tuning as used in
+   the ``meta/conf/machine/include/tune-core2.inc`` file:
+   TUNE_PKGARCH_tune-core2-32 = "core2-32"
+TUNEABI
+   An underlying Application Binary Interface (ABI) used by a particular
+   tuning in a given toolchain layer. Providers that use prebuilt
+   libraries can use the ``TUNEABI``,
+   ```TUNEABI_OVERRIDE`` <#var-TUNEABI_OVERRIDE>`__, and
+   ```TUNEABI_WHITELIST`` <#var-TUNEABI_WHITELIST>`__ variables to check
+   compatibility of tunings against their selection of libraries.
+   If ``TUNEABI`` is undefined, then every tuning is allowed. See the
+   ```sanity`` <#ref-classes-sanity>`__ class to see how the variable is
+   used.
+TUNEABI_OVERRIDE
+   If set, the OpenEmbedded system ignores the
+   ```TUNEABI_WHITELIST`` <#var-TUNEABI_WHITELIST>`__ variable.
+   Providers that use prebuilt libraries can use the
+   ``TUNEABI_OVERRIDE``, ``TUNEABI_WHITELIST``, and
+   ```TUNEABI`` <#var-TUNEABI>`__ variables to check compatibility of a
+   tuning against their selection of libraries.
+   See the ```sanity`` <#ref-classes-sanity>`__ class to see how the
+   variable is used.
+TUNEABI_WHITELIST
+   A whitelist of permissible ```TUNEABI`` <#var-TUNEABI>`__ values. If
+   ``TUNEABI_WHITELIST`` is not set, all tunes are allowed. Providers
+   that use prebuilt libraries can use the ``TUNEABI_WHITELIST``,
+   ```TUNEABI_OVERRIDE`` <#var-TUNEABI_OVERRIDE>`__, and ``TUNEABI``
+   variables to check compatibility of a tuning against their selection
+   of libraries.
+   See the ```sanity`` <#ref-classes-sanity>`__ class to see how the
+   variable is used.
+TUNECONFLICTS[feature]
+   Specifies CPU or Application Binary Interface (ABI) tuning features
+   that conflict with feature.
+   Known tuning conflicts are specified in the machine include files in
+   the `Source Directory <#source-directory>`__. Here is an example from
+   the ``meta/conf/machine/include/mips/arch-mips.inc`` include file
+   that lists the "o32" and "n64" features as conflicting with the "n32"
+   feature: TUNECONFLICTS[n32] = "o32 n64"
+TUNEVALID[feature]
+   Specifies a valid CPU or Application Binary Interface (ABI) tuning
+   feature. The specified feature is stored as a flag. Valid features
+   are specified in the machine include files (e.g.
+   ``meta/conf/machine/include/arm/arch-arm.inc``). Here is an example
+   from that file: TUNEVALID[bigendian] = "Enable big-endian mode."
+   See the machine include files in the `Source
+   Directory <#source-directory>`__ for these features.
+UBOOT_CONFIG
+   Configures the ```UBOOT_MACHINE`` <#var-UBOOT_MACHINE>`__ and can
+   also define ```IMAGE_FSTYPES`` <#var-IMAGE_FSTYPES>`__ for individual
+   cases.
+   Following is an example from the ``meta-fsl-arm`` layer. UBOOT_CONFIG
+   ??= "sd" UBOOT_CONFIG[sd] = "mx6qsabreauto_config,sdcard"
+   UBOOT_CONFIG[eimnor] = "mx6qsabreauto_eimnor_config"
+   UBOOT_CONFIG[nand] = "mx6qsabreauto_nand_config,ubifs"
+   UBOOT_CONFIG[spinor] = "mx6qsabreauto_spinor_config" In this example,
+   "sd" is selected as the configuration of the possible four for the
+   ``UBOOT_MACHINE``. The "sd" configuration defines
+   "mx6qsabreauto_config" as the value for ``UBOOT_MACHINE``, while the
+   "sdcard" specifies the ``IMAGE_FSTYPES`` to use for the U-boot image.
+   For more information on how the ``UBOOT_CONFIG`` is handled, see the
+   ```uboot-config`` <http://git.yoctoproject.org/cgit/cgit.cgi/poky/tree/meta/classes/uboot-config.bbclass>`__
+   class.
+UBOOT_ENTRYPOINT
+   Specifies the entry point for the U-Boot image. During U-Boot image
+   creation, the ``UBOOT_ENTRYPOINT`` variable is passed as a
+   command-line parameter to the ``uboot-mkimage`` utility.
+UBOOT_LOADADDRESS
+   Specifies the load address for the U-Boot image. During U-Boot image
+   creation, the ``UBOOT_LOADADDRESS`` variable is passed as a
+   command-line parameter to the ``uboot-mkimage`` utility.
+UBOOT_LOCALVERSION
+   Appends a string to the name of the local version of the U-Boot
+   image. For example, assuming the version of the U-Boot image built
+   was "2013.10", the full version string reported by U-Boot would be
+   "2013.10-yocto" given the following statement: UBOOT_LOCALVERSION =
+   "-yocto"
+UBOOT_MACHINE
+   Specifies the value passed on the ``make`` command line when building
+   a U-Boot image. The value indicates the target platform
+   configuration. You typically set this variable from the machine
+   configuration file (i.e. ``conf/machine/machine_name.conf``).
+   Please see the "Selection of Processor Architecture and Board Type"
+   section in the U-Boot README for valid values for this variable.
+UBOOT_MAKE_TARGET
+   Specifies the target called in the ``Makefile``. The default target
+   is "all".
+UBOOT_MKIMAGE_DTCOPTS
+   Options for the device tree compiler passed to mkimage '-D'
+   feature while creating FIT image in ``kernel-fitimage`` class.
+UBOOT_RD_LOADADDRESS
+   Specifies the load address for the RAM disk image.
+   During FIT image creation, the
+   ``UBOOT_RD_LOADADDRESS`` variable is used
+   in ``kernel-fitimage`` class to specify the
+   load address to be used in creating the Image Tree Source for
+   the FIT image.
+UBOOT_RD_ENTRYPOINT
+   Specifies the entrypoint for the RAM disk image.
+   During FIT image creation, the
+   ``UBOOT_RD_ENTRYPOINT`` variable is used
+   in ``kernel-fitimage`` class to specify the
+   entrypoint to be used in creating the Image Tree Source for
+   the FIT image.
+UBOOT_SUFFIX
+   Points to the generated U-Boot extension. For example, ``u-boot.sb``
+   has a ``.sb`` extension.
+   The default U-Boot extension is ``.bin``
+UBOOT_TARGET
+   Specifies the target used for building U-Boot. The target is passed
+   directly as part of the "make" command (e.g. SPL and AIS). If you do
+   not specifically set this variable, the OpenEmbedded build process
+   passes and uses "all" for the target during the U-Boot building
+   process.
+UBOOT_SIGN_ENABLE
+   Enable signing of FIT image. The default value is "0".
+UBOOT_SIGN_KEYDIR
+   Location of the directory containing the RSA key and
+   certificate used for signing FIT image.
+UBOOT_SIGN_KEYNAME
+   The name of keys used for signing U-boot FIT image stored in
+   :term:`UBOOT_SIGN_KEYDIR` directory. For e.g. dev.key key and dev.crt
+   certificate stored in :term:`UBOOT_SIGN_KEYDIR` directory will have
+   :term:`UBOOT_SIGN_KEYNAME` set to "dev".
+UNKNOWN_CONFIGURE_WHITELIST
+   Specifies a list of options that, if reported by the configure script
+   as being invalid, should not generate a warning during the
+   ```do_configure`` <#ref-tasks-configure>`__ task. Normally, invalid
+   configure options are simply not passed to the configure script (e.g.
+   should be removed from ```EXTRA_OECONF`` <#var-EXTRA_OECONF>`__ or
+   ```PACKAGECONFIG_CONFARGS`` <#var-PACKAGECONFIG_CONFARGS>`__).
+   However, common options, for example, exist that are passed to all
+   configure scripts at a class level that might not be valid for some
+   configure scripts. It follows that no benefit exists in seeing a
+   warning about these options. For these cases, the options are added
+   to ``UNKNOWN_CONFIGURE_WHITELIST``.
+   The configure arguments check that uses
+   ``UNKNOWN_CONFIGURE_WHITELIST`` is part of the
+   ```insane`` <#ref-classes-insane>`__ class and is only enabled if the
+   recipe inherits the ```autotools`` <#ref-classes-autotools>`__ class.
+UPDATERCPN
+   For recipes inheriting the
+   ```update-rc.d`` <#ref-classes-update-rc.d>`__ class, ``UPDATERCPN``
+   specifies the package that contains the initscript that is enabled.
+   The default value is "${PN}". Given that almost all recipes that
+   install initscripts package them in the main package for the recipe,
+   you rarely need to set this variable in individual recipes.
+UPSTREAM_CHECK_GITTAGREGEX
+   You can perform a per-recipe check for what the latest upstream
+   source code version is by calling ``bitbake -c checkpkg`` recipe. If
+   the recipe source code is provided from Git repositories, the
+   OpenEmbedded build system determines the latest upstream version by
+   picking the latest tag from the list of all repository tags.
+   You can use the ``UPSTREAM_CHECK_GITTAGREGEX`` variable to provide a
+   regular expression to filter only the relevant tags should the
+   default filter not work correctly. UPSTREAM_CHECK_GITTAGREGEX =
+   "git_tag_regex"
+UPSTREAM_CHECK_REGEX
+   Use the ``UPSTREAM_CHECK_REGEX`` variable to specify a different
+   regular expression instead of the default one when the package
+   checking system is parsing the page found using
+   ```UPSTREAM_CHECK_URI`` <#var-UPSTREAM_CHECK_URI>`__.
+   UPSTREAM_CHECK_REGEX = "package_regex"
+UPSTREAM_CHECK_URI
+   You can perform a per-recipe check for what the latest upstream
+   source code version is by calling ``bitbake -c checkpkg`` recipe. If
+   the source code is provided from tarballs, the latest version is
+   determined by fetching the directory listing where the tarball is and
+   attempting to find a later tarball. When this approach does not work,
+   you can use ``UPSTREAM_CHECK_URI`` to provide a different URI that
+   contains the link to the latest tarball. UPSTREAM_CHECK_URI =
+   "recipe_url"
+USE_DEVFS
+   Determines if ``devtmpfs`` is used for ``/dev`` population. The
+   default value used for ``USE_DEVFS`` is "1" when no value is
+   specifically set. Typically, you would set ``USE_DEVFS`` to "0" for a
+   statically populated ``/dev`` directory.
+   See the "`Selecting a Device
+   Manager <&YOCTO_DOCS_DEV_URL;#selecting-dev-manager>`__" section in
+   the Yocto Project Development Tasks Manual for information on how to
+   use this variable.
+USE_VT
+   When using
+   `SysVinit <&YOCTO_DOCS_DEV_URL;#new-recipe-enabling-system-services>`__,
+   determines whether or not to run a
+   `getty <http://en.wikipedia.org/wiki/Getty_%28Unix%29>`__ on any
+   virtual terminals in order to enable logging in through those
+   terminals.
+   The default value used for ``USE_VT`` is "1" when no default value is
+   specifically set. Typically, you would set ``USE_VT`` to "0" in the
+   machine configuration file for machines that do not have a graphical
+   display attached and therefore do not need virtual terminal
+   functionality.
+USER_CLASSES
+   A list of classes to globally inherit. These classes are used by the
+   OpenEmbedded build system to enable extra features (e.g.
+   ``buildstats``, ``image-mklibs``, and so forth).
+   The default list is set in your ``local.conf`` file: USER_CLASSES ?=
+   "buildstats image-mklibs image-prelink" For more information, see
+   ``meta-poky/conf/local.conf.sample`` in the `Source
+   Directory <#source-directory>`__.
+USERADD_ERROR_DYNAMIC
+   If set to ``error``, forces the OpenEmbedded build system to produce
+   an error if the user identification (``uid``) and group
+   identification (``gid``) values are not defined in any of the files
+   listed in ```USERADD_UID_TABLES`` <#var-USERADD_UID_TABLES>`__ and
+   ```USERADD_GID_TABLES`` <#var-USERADD_GID_TABLES>`__. If set to
+   ``warn``, a warning will be issued instead.
+   The default behavior for the build system is to dynamically apply
+   ``uid`` and ``gid`` values. Consequently, the
+   ``USERADD_ERROR_DYNAMIC`` variable is by default not set. If you plan
+   on using statically assigned ``gid`` and ``uid`` values, you should
+   set the ``USERADD_ERROR_DYNAMIC`` variable in your ``local.conf``
+   file as follows: USERADD_ERROR_DYNAMIC = "error" Overriding the
+   default behavior implies you are going to also take steps to set
+   static ``uid`` and ``gid`` values through use of the
+   ```USERADDEXTENSION`` <#var-USERADDEXTENSION>`__,
+   ```USERADD_UID_TABLES`` <#var-USERADD_UID_TABLES>`__, and
+   ```USERADD_GID_TABLES`` <#var-USERADD_GID_TABLES>`__ variables.
+   .. note::
+      There is a difference in behavior between setting
+      USERADD_ERROR_DYNAMIC
+      to
+      error
+      and setting it to
+      warn
+      . When it is set to
+      warn
+      , the build system will report a warning for every undefined
+      uid
+      and
+      gid
+      in any recipe. But when it is set to
+      error
+      , it will only report errors for recipes that are actually built.
+      This saves you from having to add static IDs for recipes that you
+      know will never be built.
+USERADD_GID_TABLES
+   Specifies a password file to use for obtaining static group
+   identification (``gid``) values when the OpenEmbedded build system
+   adds a group to the system during package installation.
+   When applying static group identification (``gid``) values, the
+   OpenEmbedded build system looks in ```BBPATH`` <#var-BBPATH>`__ for a
+   ``files/group`` file and then applies those ``uid`` values. Set the
+   variable as follows in your ``local.conf`` file: USERADD_GID_TABLES =
+   "files/group"
+   .. note::
+      Setting the
+      USERADDEXTENSION
+      variable to "useradd-staticids" causes the build system to use
+      static
+      gid
+      values.
+USERADD_PACKAGES
+   When inheriting the ```useradd`` <#ref-classes-useradd>`__ class,
+   this variable specifies the individual packages within the recipe
+   that require users and/or groups to be added.
+   You must set this variable if the recipe inherits the class. For
+   example, the following enables adding a user for the main package in
+   a recipe: USERADD_PACKAGES = "${PN}"
+   .. note::
+      It follows that if you are going to use the
+      USERADD_PACKAGES
+      variable, you need to set one or more of the
+      USERADD_PARAM
+      ,
+      GROUPADD_PARAM
+      , or
+      GROUPMEMS_PARAM
+      variables.
+USERADD_PARAM
+   When inheriting the ```useradd`` <#ref-classes-useradd>`__ class,
+   this variable specifies for a package what parameters should pass to
+   the ``useradd`` command if you add a user to the system when the
+   package is installed.
+   Here is an example from the ``dbus`` recipe: USERADD_PARAM_${PN} =
+   "--system --home ${localstatedir}/lib/dbus \\ --no-create-home
+   --shell /bin/false \\ --user-group messagebus" For information on the
+   standard Linux shell command ``useradd``, see
+   ` <http://linux.die.net/man/8/useradd>`__.
+USERADD_UID_TABLES
+   Specifies a password file to use for obtaining static user
+   identification (``uid``) values when the OpenEmbedded build system
+   adds a user to the system during package installation.
+   When applying static user identification (``uid``) values, the
+   OpenEmbedded build system looks in ```BBPATH`` <#var-BBPATH>`__ for a
+   ``files/passwd`` file and then applies those ``uid`` values. Set the
+   variable as follows in your ``local.conf`` file: USERADD_UID_TABLES =
+   "files/passwd"
+   .. note::
+      Setting the
+      USERADDEXTENSION
+      variable to "useradd-staticids" causes the build system to use
+      static
+      uid
+      values.
+USERADDEXTENSION
+   When set to "useradd-staticids", causes the OpenEmbedded build system
+   to base all user and group additions on a static ``passwd`` and
+   ``group`` files found in ```BBPATH`` <#var-BBPATH>`__.
+   To use static user identification (``uid``) and group identification
+   (``gid``) values, set the variable as follows in your ``local.conf``
+   file: USERADDEXTENSION = "useradd-staticids"
+   .. note::
+      Setting this variable to use static
+      uid
+      and
+      gid
+      values causes the OpenEmbedded build system to employ the
+      useradd-staticids
+      class.
+   If you use static ``uid`` and ``gid`` information, you must also
+   specify the ``files/passwd`` and ``files/group`` files by setting the
+   ```USERADD_UID_TABLES`` <#var-USERADD_UID_TABLES>`__ and
+   ```USERADD_GID_TABLES`` <#var-USERADD_GID_TABLES>`__ variables.
+   Additionally, you should also set the
+   ```USERADD_ERROR_DYNAMIC`` <#var-USERADD_ERROR_DYNAMIC>`__ variable.
+VOLATILE_LOG_DIR
+   Specifies the persistence of the target's ``/var/log`` directory,
+   which is used to house postinstall target log files.
+   By default, ``VOLATILE_LOG_DIR`` is set to "yes", which means the
+   file is not persistent. You can override this setting by setting the
+   variable to "no" to make the log directory persistent.
+WARN_QA
+   Specifies the quality assurance checks whose failures are reported as
+   warnings by the OpenEmbedded build system. You set this variable in
+   your distribution configuration file. For a list of the checks you
+   can control with this variable, see the
+   "```insane.bbclass`` <#ref-classes-insane>`__" section.
+WKS_FILE_DEPENDS
+   When placed in the recipe that builds your image, this variable lists
+   build-time dependencies. The ``WKS_FILE_DEPENDS`` variable is only
+   applicable when Wic images are active (i.e. when
+   ```IMAGE_FSTYPES`` <#var-IMAGE_FSTYPES>`__ contains entries related
+   to Wic). If your recipe does not create Wic images, the variable has
+   no effect.
+   The ``WKS_FILE_DEPENDS`` variable is similar to the
+   ```DEPENDS`` <#var-DEPENDS>`__ variable. When you use the variable in
+   your recipe that builds the Wic image, dependencies you list in the
+   ``WIC_FILE_DEPENDS`` variable are added to the ``DEPENDS`` variable.
+   With the ``WKS_FILE_DEPENDS`` variable, you have the possibility to
+   specify a list of additional dependencies (e.g. native tools,
+   bootloaders, and so forth), that are required to build Wic images.
+   Following is an example: WKS_FILE_DEPENDS = "some-native-tool" In the
+   previous example, some-native-tool would be replaced with an actual
+   native tool on which the build would depend.
+WKS_FILE
+   Specifies the location of the Wic kickstart file that is used by the
+   OpenEmbedded build system to create a partitioned image
+   (image\ ``.wic``). For information on how to create a partitioned
+   image, see the "`Creating Partitioned Images Using
+   Wic <&YOCTO_DOCS_DEV_URL;#creating-partitioned-images-using-wic>`__"
+   section in the Yocto Project Development Tasks Manual. For details on
+   the kickstart file format, see the "`OpenEmbedded Kickstart
+   (``.wks``) Reference <#ref-kickstart>`__" Chapter.
+WORKDIR
+   The pathname of the work directory in which the OpenEmbedded build
+   system builds a recipe. This directory is located within the
+   ```TMPDIR`` <#var-TMPDIR>`__ directory structure and is specific to
+   the recipe being built and the system for which it is being built.
+   The ``WORKDIR`` directory is defined as follows:
+   ${TMPDIR}/work/${MULTIMACH_TARGET_SYS}/${PN}/${EXTENDPE}${PV}-${PR}
+   The actual directory depends on several things:
+   -  TMPDIR
+      : The top-level build output directory
+   -  MULTIMACH_TARGET_SYS
+      : The target system identifier
+   -  PN
+      : The recipe name
+   -  EXTENDPE
+      : The epoch - (if
+      PE
+      is not specified, which is usually the case for most recipes, then
+      EXTENDPE
+      is blank)
+   -  PV
+      : The recipe version
+   -  PR
+      : The recipe revision
+   As an example, assume a Source Directory top-level folder name
+   ``poky``, a default Build Directory at ``poky/build``, and a
+   ``qemux86-poky-linux`` machine target system. Furthermore, suppose
+   your recipe is named ``foo_1.3.0-r0.bb``. In this case, the work
+   directory the build system uses to build the package would be as
+   follows: poky/build/tmp/work/qemux86-poky-linux/foo/1.3.0-r0
+XSERVER
+   Specifies the packages that should be installed to provide an X
+   server and drivers for the current machine, assuming your image
+   directly includes ``packagegroup-core-x11-xserver`` or, perhaps
+   indirectly, includes "x11-base" in
+   ```IMAGE_FEATURES`` <#var-IMAGE_FEATURES>`__.
+   The default value of ``XSERVER``, if not specified in the machine
+   configuration, is "xserver-xorg xf86-video-fbdev xf86-input-evdev".