# Variables Glossary

This chapter lists common variables used in the OpenEmbedded build system and gives an overview of their function and contents.

A B C D E F G H I K L M N O P R S T U V W X

### A

ABIEXTENSION
ABIEXTENSION[doc] = "Extension to the Application Binary Interface (ABI) field of the GNU canonical architecture name (e.g. "eabi")."

  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
ALLOW_EMPTY[doc] = "Specifies whether to produce an output package even if it is 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` 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
ALTERNATIVE[doc] = "Lists commands in a package that need an alternative binary naming scheme."

  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`" section.
ALTERNATIVE_LINK_NAME
ALTERNATIVE_LINK_NAME[doc] = "Used by the alternatives system to map duplicated commands to actual locations."

  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/`.

  If `ALTERNATIVE_LINK_NAME` is not defined, it defaults to `${bindir}/name`.

  For more information on the alternatives system, see the "`update-alternatives.bbclass`" section.

ALTERNATIVE_PRIORITY
ALTERNATIVE_PRIORITY[doc] = "Used by the alternatives system to create default priorities for duplicated commands."

  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`" section.

ALTERNATIVE_TARGET
ALTERNATIVE_TARGET[doc] = "Used by the alternatives system to create default link locations for duplicated commands."

  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"

  If `ALTERNATIVE_TARGET` is not defined, it inherits the value from the `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` task while retaining support for the command if necessary.

  For more information on the alternatives system, see the "`update-alternatives.bbclass`" section.

APPEND
APPEND[doc] = "An override list of append strings for target specified using LABELS."

  An override list of append strings for each target specified with `LABELS`.

  See the `grub-efi` class for more information on how this variable is used.

AR
AR[doc] = "Minimal command and arguments to run 'ar'."

  The minimal command and arguments used to run `ar`.

ARCHIVER_MODE
ARCHIVER_MODE[doc] = "Controls archive creation used when releasing source files."

  When used with the `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.
AS
AS[doc] = "Minimal command and arguments to run the assembler."

  Minimal command and arguments needed to run the assembler.

ASSUME_PROVIDED
ASSUME_PROVIDED[doc] = "Lists recipe names (PN values) BitBake does not attempt to build."

  Lists recipe names (`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
ASSUME_SHLIBS[doc] = Provides additional shlibs provider mapping information, which adds to or overwrites the information provided automatically by the system."

  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
AUTHOR[doc] = "Email address used to contact the original author or authors in order to send patches and forward bugs."

  The email address used to contact the original author or authors in order to send patches and forward bugs.

AUTO_LIBNAME_PKGS
AUTO_LIBNAME_PKGS[doc] = "Specifies which packages should be checked for libraries and renamed according to Debian library package naming."

  When the `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
AUTO_SYSLINUXMENU[doc] = "Enables creating an automatic menu for the syslinux bootloader."

  Enables creating an automatic menu for the syslinux bootloader. You must set this variable in your recipe. The `syslinux` class checks this variable.

AUTOREV
AUTOREV[doc] = "When SRCREV is set to the value of this variable, it specifies to use the latest source revision in the repository."

  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` contains `${``SRCPV``}`. For example, suppose you have a kernel recipe that inherits the kernel class and you use the previous statement. In this example, `${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" section in the Yocto Project Development Tasks Manual.

AVAILTUNES
AVAILTUNES[doc] = "The list of defined CPU and Application Binary Interface (ABI) tunings (i.e. "tunes") available for use by the OpenEmbedded build system."

  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 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" section in the BitBake User Manual for more information.

### B

B
B[doc] = "The Build Directory. The OpenEmbedded build system places generated objects into the Build Directory during a recipe's build process."

  The directory within the 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` 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
BAD_RECOMMENDATIONS[doc] = "A list of packages not to install despite being recommended by a recipe. Support for this variable exists only when using the IPK packaging backend."

  Lists "recommended-only" packages to not install. Recommended-only packages are packages installed only through the `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` 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` and the `PACKAGE_EXCLUDE` variables for related information.

BASE_LIB
BASE_LIB[doc] = "The library directory name for the CPU or Application Binary Interface (ABI) tune."

  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" 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. If Multilib is not being used, the value defaults to "lib".

BASE_WORKDIR
BASE_WORKDIR[doc] = "Points to the base of the work directory for all recipes."

  Points to the base of the work directory for all recipes. The default value is "${TMPDIR}/work".

BB_ALLOWED_NETWORKS
BB_ALLOWED_NETWORKS[doc] = "A list of hosts that the fetcher is allowed to use to obtain the required source code."

  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"

    ### Important

    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` 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` 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
BB_DANGLINGAPPENDS_WARNONLY[doc] = "Defines how BitBake handles situations where an append file (.bbappend) has no corresponding recipe file (.bb)."

  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: Here is an example:

           BB_DANGLINGAPPENDS_WARNONLY = "1"

BB_DISKMON_DIRS
BB_DISKMON_DIRS[doc] = "Monitors disk space and available inodes during the build and allows you to control the build based on these parameters."

  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. 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` 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
BB_DISKMON_WARNINTERVAL[doc] = "Defines the disk space and free inode warning intervals. To set these intervals, define the variable in the conf/local.conf file in the Build Directory."

  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.

  If you are going to use the `BB_DISKMON_WARNINTERVAL` variable, you must also use the `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
BB_GENERATE_MIRROR_TARBALLS[doc] = "Causes tarballs of the source control repositories to be placed in the DL_DIR directory."

  Causes tarballs of the source control repositories (e.g. Git repositories), including metadata, to be placed in the `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.

  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
BB_NUMBER_THREADS[doc] = "The maximum number of tasks BitBake should run in parallel at any one time. This variable is automatically configured to be equal to the number of build system cores."

  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" section in the Yocto Project Development Tasks Manual.

BB_SERVER_TIMEOUT
BB_SERVER_TIMEOUT [doc] = "Specifies the time (in seconds) after which to unload the BitBake server due to inactivity."

  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
BBCLASSEXTEND[doc] = "Allows you to extend a recipe so that it builds variants of the software. Common variants for recipes are 'native', 'cross', 'nativesdk', and multilibs."

  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`; "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"

  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` 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
BBFILE_COLLECTIONS[doc] = "Lists the names of configured layers. These names are used to find the other BBFILE_* variables."

  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
BBFILE_PATTERN[doc] = "Variable that expands to match files from BBFILES in a particular layer. This variable is used in the layer.conf file and must be suffixed with the name of a layer."

  Variable that expands to match files from `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
BBFILE_PRIORITY[doc] = "Assigns the priority for recipe files in each layer. Setting this variable allows you to prioritize a layer against other layers that contain the same recipe."

  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` 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).

  You can use the command `bitbake-layers show-layers` to list all configured layers along with their priorities.

BBFILES
BBFILES[doc] = "A space-separated list of recipe files BitBake uses to build software."

  A space-separated list of recipe files BitBake uses to build software.

  When specifying recipe files, you can pattern match using Python's `glob` syntax. For details on the syntax, see the documentation by following the previous link.

BBFILES_DYNAMIC
BBFILES_DYNAMIC[doc] = "Activates content when identified layers are present."

  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
BBINCLUDELOGS[doc] = "Variable that controls how BitBake displays logs on build failure."

  Variable that controls how BitBake displays logs on build failure.

BBINCLUDELOGS_LINES
BBINCLUDELOGS_LINES[doc] = "Amount of log lines printed on failure."

  If `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
BBLAYERS[doc] = "Lists the layers to enable during the build. This variable is defined in the bblayers.conf configuration file."

  Lists the layers to enable during the build. This variable is defined in the `bblayers.conf` configuration file in the 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
BBMASK[doc] = "Prevents BitBake from processing specific recipes or recipe append files."

  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 .

  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"

  When specifying a directory name, use the trailing slash character to ensure you match just that directory name.

BBMULTICONFIG
BBMULTICONFIG[doc] = "Specifies each separate configuration when you are building targets with multiple configurations."

  Specifies each 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 `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" section in the Yocto Project Development Tasks Manual.

BBPATH
BBPATH[doc] = "Used by BitBake to locate .bbclass and configuration files. This variable is analogous to the PATH variable."

  Used by BitBake to locate `.bbclass` and configuration files. This variable is analogous to the `PATH` variable.

  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
BBSERVER[doc] = "Points to the BitBake remote server."

  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`. Consequently, `BBSERVER` is excluded from checksum and dependency data.

BINCONFIG
BINCONFIG[doc] = "When inheriting the binconfig-disabled class, this variable specifies binary configuration scripts to disable in favor of using pkg-config to query the information."

  When inheriting the `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
BINCONFIG_GLOB[doc] = "When inheriting binconfig.bbclass from a recipe, this variable specifies a wildcard for configuration scripts that need editing."

  When inheriting the `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.

  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. You can also find general information on the class in the "`binconfig.bbclass`" section.

BP
BP[doc] = "The base recipe name and version but without any special recipe name suffix (i.e. -native, lib64-, and so forth). BP is comprised of ${BPN}-${PV}"

  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
BPN[doc] = "This variable is a version of the PN variable but removes common suffixes and prefixes."

  This variable is a version of the `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` and `SPECIAL_PKGSUFFIX` variables, respectively.

BUGTRACKER
BUGTRACKER[doc] = "Specifies a URL for an upstream bug tracking website for a recipe."

  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
BUILD_ARCH[doc] = "The name of the building architecture (e.g. i686)."

  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
BUILD_AS_ARCH[doc] = "Specifies the architecture-specific assembler flags for the build host."

  Specifies the architecture-specific assembler flags for the build host. By default, the value of `BUILD_AS_ARCH` is empty.

BUILD_CC_ARCH
BUILD_CC_ARCH[doc] = "Specifies the architecture-specific C compiler flags for the build host."

  Specifies the architecture-specific C compiler flags for the build host. By default, the value of `BUILD_CC_ARCH` is empty.

BUILD_CCLD
BUILD_CCLD[doc] = "Specifies the linker command to be used for the build host when the C compiler is being used as the linker."

  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`, assuming `BUILD_CC_ARCH` is set.

BUILD_CFLAGS
BUILD_CFLAGS[doc] = "Specifies the flags to pass to the C compiler when building for the build host."

  Specifies the flags to pass to the C compiler when building for the build host. When building in the `-native` context, `CFLAGS` is set to the value of this variable by default.

BUILD_CPPFLAGS
BUILD_CPPFLAGS[doc] = "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."

  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` is set to the value of this variable by default.

BUILD_CXXFLAGS
BUILD_CXXFLAGS[doc] = "Specifies the flags to pass to the C++ compiler when building for the build host."

  Specifies the flags to pass to the C++ compiler when building for the build host. When building in the `-native` context, `CXXFLAGS` is set to the value of this variable by default.

BUILD_FC
BUILD_FC[doc] = "Specifies the Fortran compiler command for the build host."

  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`, assuming `BUILD_CC_ARCH` is set.

BUILD_LD
BUILD_LD[doc] = "Specifies the linker command for the build host."

  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`, assuming `BUILD_LD_ARCH` is set.

BUILD_LD_ARCH
BUILD_LD_ARCH[doc] = "Specifies architecture-specific linker flags for the build."

  Specifies architecture-specific linker flags for the build host. By default, the value of `BUILD_LD_ARCH` is empty.

BUILD_LDFLAGS
BUILD_LDFLAGS[doc] = "Specifies the flags to pass to the linker when building for the build host."

  Specifies the flags to pass to the linker when building for the build host. When building in the `-native` context, `LDFLAGS` is set to the value of this variable by default.

BUILD_OPTIMIZATION
BUILD_OPTIMIZATION[doc] = "Specifies the optimization flags passed to the C compiler when building for the build host or the SDK."

  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` and `BUILDSDK_CFLAGS` default values.

  The default value of the `BUILD_OPTIMIZATION` variable is "-O2 -pipe".

BUILD_OS
BUILD_OS[doc] = "The operating system (in lower case) of the building architecture (e.g. Linux)."

  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
BUILD_PREFIX[doc] = "The toolchain binary prefix used for native recipes."

  The toolchain binary prefix used for native recipes. The OpenEmbedded build system uses the `BUILD_PREFIX` value to set the `TARGET_PREFIX` when building for `native` recipes.

BUILD_STRIP
BUILD_STRIP[doc] = "Specifies the command to be used to strip debugging symbols from binaries produced for the build host."

  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``}strip`.

BUILD_SYS
BUILD_SYS[doc] = "The toolchain binary prefix used for native recipes."

  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`, `BUILD_VENDOR`, and `BUILD_OS`. You do not need to set the `BUILD_SYS` variable yourself.

BUILD_VENDOR
BUILD_VENDOR[doc] = "The vendor name to use when building for the build host."

  Specifies the vendor name to use when building for the build host. The default value is an empty string ("").

BUILDDIR
BUILDDIR[doc] = "Points to the location of the Build Directory."

  Points to the location of the Build Directory. You can define this directory indirectly through the `&OE_INIT_FILE;` 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
BUILDHISTORY_COMMIT[doc] = "When inheriting the buildhistory class, this variable specifies whether or not to commit the build history output in a local Git repository."

  When inheriting the `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
BUILDHISTORY_COMMIT_AUTHOR[doc] = "When inheriting the buildhistory class, this variable specifies the author to use for each Git commit."

  When inheriting the `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` 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
BUILDHISTORY_DIR[doc] = "When inheriting the buildhistory class, this variable specifies the directory in which build history information is kept."

  When inheriting the `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
BUILDHISTORY_FEATURES[doc] = "When inheriting the buildhistory class, this variable specifies the build history features to be enabled."

  When inheriting the `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" 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 (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
BUILDHISTORY_IMAGE_FILES[doc] = "When inheriting the 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."

  When inheriting the `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
BUILDHISTORY_PUSH_REPO[doc] = "When inheriting the buildhistory class, this variable optionally specifies a remote repository to which build history pushes Git changes."

  When inheriting the `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` 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
BUILDSDK_CFLAGS[doc] = "Specifies the flags to pass to the C compiler when building for the SDK."

  Specifies the flags to pass to the C compiler when building for the SDK. When building in the `nativesdk-` context, `CFLAGS` is set to the value of this variable by default.

BUILDSDK_CPPFLAGS
BUILDSDK_CPPFLAGS[doc] = "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."

  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` is set to the value of this variable by default.

BUILDSDK_CXXFLAGS
BUILDSDK_CXXFLAGS[doc] = "Specifies the flags to pass to the C++ compiler when building for the SDK."

  Specifies the flags to pass to the C++ compiler when building for the SDK. When building in the `nativesdk-` context, `CXXFLAGS` is set to the value of this variable by default.

BUILDSDK_LDFLAGS
BUILDSDK_LDFLAGS[doc] = "Specifies the flags to pass to the linker when building for the SDK."

  Specifies the flags to pass to the linker when building for the SDK. When building in the `nativesdk-` context, `LDFLAGS` is set to the value of this variable by default.

BUILDSTATS_BASE
BUILDSTATS_BASE[doc] = "Points to the location of the directory that holds build statistics when you use and enable the buildstats class."

  Points to the location of the directory that holds build statistics when you use and enable the `buildstats` class. The `BUILDSTATS_BASE` directory defaults to `${``TMPDIR``}/buildstats/`.

BUSYBOX_SPLIT_SUID
BUSYBOX_SPLIT_SUID[doc] = "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."

  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 a single output executable file. Set the variable to "0" to split the output file.

### C

CACHE
CACHE[doc] = "The directory BitBake uses to store a cache of the metadata."

  Specifies the directory BitBake uses to store a cache of the Metadata so it does not need to be parsed every time BitBake is started.

CC
CC[doc] = "Minimum command and arguments to run the C compiler."

  The minimal command and arguments used to run the C compiler.

CFLAGS
CFLAGS[doc] = "Flags passed to the C compiler for the target system. This variable evaluates to the same as TARGET_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` when building for the target

  - `BUILD_CFLAGS` when building for the build host (i.e. `-native`)

  - `BUILDSDK_CFLAGS` when building for an SDK (i.e. `nativesdk-`)

CLASSOVERRIDE
CLASSOVERRIDE[doc] = "An internal variable specifying the special class override that should currently apply (e.g. "class-target", "class-native", and so forth)."

  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`, `nativesdk`, and so forth) set the variable to appropriate values.

  `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`.
CLEANBROKEN
CLEANBROKEN[doc] = "Prevents the build system from running 'make clean' during the do_configure task."

  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` task, which is the default behavior.

COMBINED_FEATURES
COMBINED_FEATURES[doc] = "A set of features common between MACHINE_FEATURES and DISTRO_FEATURES."

  Provides a list of hardware features that are enabled in both `MACHINE_FEATURES` and `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
COMMON_LICENSE_DIR[doc] = "Points to meta/files/common-licenses in the Source Directory, which is where generic license files reside."

  Points to `meta/files/common-licenses` in the Source Directory, which is where generic license files reside.

COMPATIBLE_HOST
COMPATIBLE_HOST[doc] = "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."

  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`. 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
COMPATIBLE_MACHINE[doc] = "A regular expression that resolves to one or more target machines with which a recipe is compatible."

  A regular expression that resolves to one or more target machines with which a recipe is compatible. The regular expression is matched against `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
COMPLEMENTARY_GLOB[doc] = "Defines wildcards to match when installing a list of complementary packages for all the packages installed in an image."

  Defines wildcards to match when installing a list of complementary packages for all the packages explicitly (or implicitly) installed in an image.

  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`. 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
COMPONENTS_DIR[doc] = "Stores sysroot components for each recipe."

  Stores sysroot components for each recipe. The OpenEmbedded build system uses `COMPONENTS_DIR` when constructing recipe-specific sysroots for other recipes.

  The default is "`${``STAGING_DIR``}-components`." (i.e. "`${``TMPDIR``}/sysroots-components`").

CONF_VERSION
CONF_VERSION[doc] = "Tracks the version of local.conf. Increased each time build/conf/ changes incompatibly."

  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
CONFFILES[doc] = "Identifies editable or configurable files that are part of a package."

  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.

  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
CONFIG_INITRAMFS_SOURCE[doc] = "Identifies the initial RAM filesystem (initramfs) source files. The OpenEmbedded build system receives and uses this kernel Kconfig variable as an environment variable."

  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" section in the Yocto Project Development Tasks Manual.

CONFIG_SITE
CONFIG_SITE[doc] = "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."

  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
CONFIGURE_FLAGS[doc] = "The minimal arguments for GNU configure."

  The minimal arguments for GNU configure.

CONFLICT_DISTRO_FEATURES
CONFLICT_DISTRO_FEATURES[doc] = "When a recipe inherits the distro_features_check class, this variable identifies distribution features that would be in conflict should the recipe be built."

  When inheriting the `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
COPYLEFT_LICENSE_EXCLUDE[doc] = "Licenses to exclude in the source archived by the archiver class."

  A space-separated list of licenses to exclude from the source archived by the `archiver` class. In other words, if a license in a recipe's `LICENSE` value is in the value of `COPYLEFT_LICENSE_EXCLUDE`, then its source is not archived by the class.

  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` class, which is inherited by the `archiver` class.
COPYLEFT_LICENSE_INCLUDE
COPYLEFT_LICENSE_INCLUDE[doc] = "Licenses to include in the source archived by the archiver class."

  A space-separated list of licenses to include in the source archived by the `archiver` class. In other words, if a license in a recipe's `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` class, which is inherited by the `archiver` class. The default value includes "GPL*", "LGPL*", and "AGPL*".

COPYLEFT_PN_EXCLUDE
COPYLEFT_PN_EXCLUDE[doc] = "Recipes to exclude in the source archived by the archiver class."

  A list of recipes to exclude in the source archived by the `archiver` class. The `COPYLEFT_PN_EXCLUDE` variable overrides the license inclusion and exclusion caused through the `COPYLEFT_LICENSE_INCLUDE` and `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` class, which is inherited by the `archiver` class.

COPYLEFT_PN_INCLUDE
COPYLEFT_PN_INCLUDE[doc] = "Recipes to include in the source archived by the archiver class."

  A list of recipes to include in the source archived by the `archiver` class. The `COPYLEFT_PN_INCLUDE` variable overrides the license inclusion and exclusion caused through the `COPYLEFT_LICENSE_INCLUDE` and `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` class, which is inherited by the `archiver` class.

COPYLEFT_RECIPE_TYPES
COPYLEFT_RECIPE_TYPES[doc] = "Recipe types to include in the source archived by the archiver class."

  A space-separated list of recipe types to include in the source archived by the `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` class, which is inherited by the `archiver` class.

COPY_LIC_DIRS
COPY_LIC_DIRS[doc] = "If set to "1" along with the 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."

  If set to "1" along with the `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.

  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
COPY_LIC_MANIFEST[doc] = "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."

  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.

  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
CORE_IMAGE_EXTRA_INSTALL[doc] = "Specifies the list of packages to be added to the image. You should only set this variable in the conf/local.conf file in the Build Directory."

  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.

  This variable replaces `POKY_EXTRA_INSTALL`, which is no longer supported.

COREBASE
COREBASE[doc] = "Specifies the parent directory of the OpenEmbedded-Core Metadata layer (i.e. meta)."

  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
COREBASE_FILES[doc] = "Lists files from the COREBASE directory that should be copied other than the layers listed in the bblayers.conf file."

  Lists files from the `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
CPP[doc] = "Minimum command and arguments to run the C preprocessor."

  The minimal command and arguments used to run the C preprocessor.

CPPFLAGS
CPPFLAGS[doc] = "Specifies the flags to pass to the C pre-processor (i.e. to both the C and the C++ compilers)."

  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` when building for the target

  - `BUILD_CPPFLAGS` when building for the build host (i.e. `-native`)

  - `BUILDSDK_CPPFLAGS` when building for an SDK (i.e. `nativesdk-`)

CROSS_COMPILE
CROSS_COMPILE[doc] = "The toolchain binary prefix for the target tools."

  The toolchain binary prefix for the target tools. The `CROSS_COMPILE` variable is the same as the `TARGET_PREFIX` variable.

  The OpenEmbedded build system sets the `CROSS_COMPILE` variable only in certain contexts (e.g. when building for kernel and kernel module recipes).

CVSDIR
CVSDIR[doc] = "The directory where cvs checkouts will be stored in."

  The directory in which files checked out under the CVS system are stored.

CXX
CXX[doc] = "Minimum command and arguments to run the C++ compiler."

  The minimal command and arguments used to run the C++ compiler.

CXXFLAGS
CXXFLAGS[doc] = "Specifies the flags to pass to the C++ compiler."

  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` when building for the target

  - `BUILD_CXXFLAGS` when building for the build host (i.e. `-native`)

  - `BUILDSDK_CXXFLAGS` when building for an SDK (i.e. `nativesdk-`)

### D

D
D[doc] = "The destination directory."

  The destination directory. The location in the Build Directory where components are installed by the `do_install` task. This location defaults to:

           ${WORKDIR}/image

  ### Caution

  Tasks that read from or write to this directory should run under fakeroot.
DATE
DATE[doc] = "The date the build was started using YMD format."

  The date the build was started. Dates appear using the year, month, and day (YMD) format (e.g. "20150209" for February 9th, 2015).

DATETIME
DATETIME[doc] = "The date and time the build was started."

  The date and time on which the current build started. The format is suitable for timestamps.

DEBIAN_NOAUTONAME
DEBIAN_NOAUTONAME[doc] = "Prevents a particular package from being renamed according to Debian package naming."

  When the `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
DEBIANNAME[doc] = "Allows you to override the library name for an individual package for Debian library package renaming."

  When the `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
DEBUG_BUILD[doc] = "Specifies to build packages with debugging information. This influences the value of the SELECTED_OPTIMIZATION variable."

  Specifies to build packages with debugging information. This influences the value of the `SELECTED_OPTIMIZATION` variable.

DEBUG_OPTIMIZATION
DEBUG_OPTIMIZATION[doc] = "The options to pass in TARGET_CFLAGS and CFLAGS when compiling a system for debugging. This variable defaults to '-O -fno-omit-frame-pointer -g'."

  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
DEFAULT_PREFERENCE[doc] = "Specifies a weak bias for recipe selection priority."

  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.

  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
DEFAULTTUNE[doc] = "The default CPU and Application Binary Interface (ABI) tunings (i.e. the "tune") used by the OpenEmbedded build system."

  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`.

  The default tune is either implicitly or explicitly set by the machine (`MACHINE`). However, you can override the setting using available tunes as defined with `AVAILTUNES`.

DEPENDS
DEPENDS[doc] = "Lists a recipe's build-time dependencies (i.e. other recipe files)."

  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*` variables, by the time the `do_configure` task for `foo` runs. This mechanism is implemented by having `do_configure` depend on the `do_populate_sysroot` task of each recipe listed in `DEPENDS`, through a `[``deptask``]` declaration in the `base` class.

  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` class and the `EXTRANATIVEPATH` variable.

  ### Notes

  - `DEPENDS` is a list of recipe names. Or, to be more precise, it is a list of `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" 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` variable. You can also see the "Tasks" and "Dependencies" sections in the BitBake User Manual for additional information on tasks and dependencies.

DEPLOY_DIR
DEPLOY_DIR[doc] = "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."

  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 as `${TMPDIR}/deploy`.

  For more information on the structure of the Build Directory, see "The Build Directory - `build/`" section. For more detail on the contents of the `deploy` directory, see the "Images", "Package Feeds", and "Application Development SDK" sections all in the Yocto Project Overview and Concepts Manual.

DEPLOY_DIR_DEB
DEPLOY_DIR_DEB[doc] = "Points to a Debian-specific 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."

  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` contains "package_deb".

  The BitBake configuration file initially defines the `DEPLOY_DIR_DEB` variable as a sub-folder of `DEPLOY_DIR`:

           DEPLOY_DIR_DEB = "${DEPLOY_DIR}/deb"

  The `package_deb` class uses the `DEPLOY_DIR_DEB` variable to make sure the `do_package_write_deb` task writes Debian packages into the appropriate folder. For more information on how packaging works, see the "Package Feeds" section in the Yocto Project Overview and Concepts Manual.

DEPLOY_DIR_IMAGE
DEPLOY_DIR_IMAGE[doc] = "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."

  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 `${MACHINE}` name. By default, this directory resides within the Build Directory as `${DEPLOY_DIR}/images/${MACHINE}/`.

  For more information on the structure of the Build Directory, see "The Build Directory - `build/`" section. For more detail on the contents of the `deploy` directory, see the "Images" and "Application Development SDK" sections both in the Yocto Project Overview and Concepts Manual.

DEPLOY_DIR_IPK
DEPLOY_DIR_IPK[doc] = "Points to a IPK-specific 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."

  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` contains "package_ipk".

  The BitBake configuration file initially defines this variable as a sub-folder of `DEPLOY_DIR`:

           DEPLOY_DIR_IPK = "${DEPLOY_DIR}/ipk"

  The `package_ipk` class uses the `DEPLOY_DIR_IPK` variable to make sure the `do_package_write_ipk` task writes IPK packages into the appropriate folder. For more information on how packaging works, see the "Package Feeds" section in the Yocto Project Overview and Concepts Manual.

DEPLOY_DIR_RPM
DEPLOY_DIR_RPM[doc] = "Points to a RPM-specific 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."

  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` contains "package_rpm".

  The BitBake configuration file initially defines this variable as a sub-folder of `DEPLOY_DIR`:

           DEPLOY_DIR_RPM = "${DEPLOY_DIR}/rpm"

  The `package_rpm` class uses the `DEPLOY_DIR_RPM` variable to make sure the `do_package_write_rpm` task writes RPM packages into the appropriate folder. For more information on how packaging works, see the "Package Feeds" section in the Yocto Project Overview and Concepts Manual.

DEPLOY_DIR_TAR
DEPLOY_DIR_TAR[doc] = "Points to a tarball 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."

  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` contains "package_tar".

  The BitBake configuration file initially defines this variable as a sub-folder of `DEPLOY_DIR`:

           DEPLOY_DIR_TAR = "${DEPLOY_DIR}/tar"

  The `package_tar` class uses the `DEPLOY_DIR_TAR` variable to make sure the `do_package_write_tar` task writes TAR packages into the appropriate folder. For more information on how packaging works, see the "Package Feeds" section in the Yocto Project Overview and Concepts Manual.

DEPLOYDIR
DEPLOYDIR[doc] = "For recipes that inherit the deploy class, the DEPLOYDIR points to a temporary work area for deployed files."

  When inheriting the `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}"

  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` afterwards.

DESCRIPTION
DESCRIPTION[doc] = "The package description used by package managers. If not set, DESCRIPTION takes the value of the SUMMARY variable."

  The package description used by package managers. If not set, `DESCRIPTION` takes the value of the `SUMMARY` variable.

DISTRO
DISTRO[doc] = "The short name of the distribution. If the variable is blank, meta/conf/distro/defaultsetup.conf will be used."

  The short name of the distribution. For information on the long name of the distribution, see the `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.

  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 that contains the distribution configuration. The value for `DISTRO` must not contain spaces, and is typically all lower-case.

  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
DISTRO_CODENAME[doc] = "Specifies a codename for the distribution being built."

  Specifies a codename for the distribution being built.

DISTRO_EXTRA_RDEPENDS
DISTRO_EXTRA_RDEPENDS[doc] = "Specifies a list of distro-specific packages to add to all images. The variable only applies to the images that include packagegroup-base."

  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
DISTRO_EXTRA_RRECOMMENDS[doc] = "Specifies a list of distro-specific packages to add to all images if the packages exist. The list of packages are automatically installed but you can remove them."

  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
DISTRO_FEATURES[doc] = "The features enabled for the distribution."

  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` 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" section.

DISTRO_FEATURES_BACKFILL
DISTRO_FEATURES_BACKFILL[doc] = "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 and it is not intended to be user-configurable."

  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 section for more information.

DISTRO_FEATURES_BACKFILL_CONSIDERED
DISTRO_FEATURES_BACKFILL_CONSIDERED[doc] = "Features from DISTRO_FEATURES_BACKFILL that should not be backfilled (i.e. added to DISTRO_FEATURES) during the build."

  Features from `DISTRO_FEATURES_BACKFILL` that should not be backfilled (i.e. added to `DISTRO_FEATURES`) during the build. See the "Feature Backfilling" section for more information.

DISTRO_FEATURES_DEFAULT
DISTRO_FEATURES_DEFAULT[doc] = "Provides the default list of distro features with the exception of any libc-specific features."

  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` 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
DISTRO_FEATURES_FILTER_NATIVE[doc] = "Specifies a list of features that if present in the target DISTRO_FEATURES value should be included in DISTRO_FEATURES when building native recipes."

  Specifies a list of features that if present in the target `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` variable.

DISTRO_FEATURES_FILTER_NATIVESDK
DISTRO_FEATURES_FILTER_NATIVESDK[doc] = "Specifies a list of features that if present in the target DISTRO_FEATURES value should be included in DISTRO_FEATURES when building nativesdk recipes."

  Specifies a list of features that if present in the target `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` variable.

DISTRO_FEATURES_NATIVE
DISTRO_FEATURES_NATIVE[doc] = "Specifies a list of features that should be included in DISTRO_FEATURES when building native recipes."

  Specifies a list of features that should be included in `DISTRO_FEATURES` when building native recipes. This variable is used in addition to the features filtered using the `DISTRO_FEATURES_FILTER_NATIVE` variable.

DISTRO_FEATURES_NATIVESDK
DISTRO_FEATURES_NATIVESDK[doc] = "Specifies a list of features that should be included in DISTRO_FEATURES when building nativesdk recipes."

  Specifies a list of features that should be included in `DISTRO_FEATURES` when building nativesdk recipes. This variable is used in addition to the features filtered using the `DISTRO_FEATURES_FILTER_NATIVESDK` variable.

DISTRO_NAME
DISTRO_NAME[doc] = "The long name of the distribution."

  The long name of the distribution. For information on the short name of the distribution, see the `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.

  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 that contains the distribution configuration.

  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
DISTRO_VERSION[doc] = "The version of the distribution."

  The version of the distribution.

DISTROOVERRIDES
DISTROOVERRIDES[doc] = "A colon-separated list of overrides specific to the current distribution."

  A colon-separated list of overrides specific to the current distribution. By default, this list includes the value of `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`.

DL_DIR
DL_DIR[doc] = "The central download directory used by the build process to store downloads. By default, the directory is 'downloads' in the Build Directory."

  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` 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.

           #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.

  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" chapter. You can also refer to the "Working Behind a Network Proxy" Wiki page.

DOC_COMPRESS
DOC_COMPRESS[doc] = "When inheriting the compress_doc class, this variable sets the compression policy used when the OpenEmbedded build system compresses man pages and info pages."

  When inheriting the `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.

### E

EFI_PROVIDER
EFI_PROVIDER[doc] = "When building bootable images (i.e. where hddimg, iso, or wic.vmdk is in IMAGE_FSTYPES), the EFI_PROVIDER variable specifies the EFI bootloader to use."

  When building bootable images (i.e. where `hddimg`, `iso`, or `wic.vmdk` is in `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` and `image-live` classes for more information.

ENABLE_BINARY_LOCALE_GENERATION
ENABLE_BINARY_LOCALE_GENERATION[doc] = "Controls which locales for glibc are generated during the build. The variable is useful if the target device has 64Mbytes of RAM or less."

  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
ERR_REPORT_DIR[doc] = "When used with the report-error class, specifies the path used for storing the debug files created by the error reporting tool, which allows you to submit build errors you encounter to a central database."

  When used with the `report-error` class, specifies the path used for storing the debug files created by 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``}/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
ERROR_QA[doc] = "Specifies the quality assurance checks whose failures are reported as errors by the OpenEmbedded build system."

  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`" section.

EXCLUDE_FROM_SHLIBS
EXCLUDE_FROM_SHLIBS[doc] = "Causes the OpenEmbedded build system's shared libraries resolver to exclude an entire package when scanning for shared libraries."

  Triggers the OpenEmbedded build system's shared libraries resolver to exclude an entire package when scanning for shared libraries.

  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` 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
EXCLUDE_FROM_WORLD[doc] = "Directs BitBake to exclude a recipe from world builds (i.e. bitbake 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.

  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
EXTENDPE[doc] = "Used with file and pathnames to create a prefix for a recipe's version based on the recipe's PE value. If PE is set and greater than zero for a recipe, EXTENDPE becomes that value."

  Used with file and pathnames to create a prefix for a recipe's version based on the recipe's `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` variable for an example.

EXTENDPKGV
EXTENDPKGV[doc] = "The full package version specification as it appears on the final packages produced by a recipe."

  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
EXTERNAL_KERNEL_TOOLS[doc] = "Indicates kernel tools are external to the source tree."

  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` class in `meta/classes` to see how the variable is used.

EXTERNALSRC
EXTERNALSRC[doc] = "If externalsrc.bbclass is inherited, this variable points to the source tree, which is outside of the OpenEmbedded build system."

  When inheriting the `externalsrc` class, this variable points to the source tree, which is outside of the OpenEmbedded build system. When set, this variable sets the `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`" section. You can also find information on how to use this variable in the "Building Software from an External Source" section in the Yocto Project Development Tasks Manual.

EXTERNALSRC_BUILD
EXTERNALSRC_BUILD[doc] = "If externalsrc.bbclass is inherited, this variable points to the directory in which the recipe's source code is built, which is outside of the OpenEmbedded build system."

  When inheriting the `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` variable, which is what the OpenEmbedded build system uses to locate the Build Directory.

  For more information on `externalsrc.bbclass`, see the "`externalsrc.bbclass`" section. You can also find information on how to use this variable in the "Building Software from an External Source" section in the Yocto Project Development Tasks Manual.

EXTRA_AUTORECONF
EXTRA_AUTORECONF[doc] = "Extra options passed to the autoreconf command, which is executed during do_configure."

  For recipes inheriting the `autotools` class, you can use `EXTRA_AUTORECONF` to specify extra options to pass to the `autoreconf` command that is executed during the `do_configure` task.

  The default value is "--exclude=autopoint".

EXTRA_IMAGE_FEATURES
EXTRA_IMAGE_FEATURES[doc] = "The list of additional features to include in an image. Configure this variable in the conf/local.conf file in the Build Directory."

  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. Although you can use this variable from within a recipe, best practices dictate that you do not.

  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" 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"
                           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" 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`" section in the Yocto Project Development Tasks Manual.

EXTRA_IMAGECMD
EXTRA_IMAGECMD[doc] = "Specifies additional options for the image creation command that has been specified in IMAGE_CMD. When setting this variable, you should use an override for the associated image type."

  Specifies additional options for the image creation command that has been specified in `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
EXTRA_IMAGEDEPENDS[doc] = "A list of recipes to build that do not provide packages for installing into the root filesystem. Use this variable to list recipes that are required to build the final image, but not needed in the root filesystem."

  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.

  To add packages to the root filesystem, see the various `*RDEPENDS` and `*RRECOMMENDS` variables.

EXTRANATIVEPATH
EXTRANATIVEPATH[doc] = "A list of subdirectories of ${STAGING_BINDIR_NATIVE} added to the beginning of the environment variable PATH."

  A list of subdirectories of `${``STAGING_BINDIR_NATIVE``}` added to the beginning of the environment variable `PATH`. As an example, the following prepends "${STAGING_BINDIR_NATIVE}/foo:${STAGING_BINDIR_NATIVE}/bar:" to `PATH`:

           EXTRANATIVEPATH = "foo bar"

EXTRA_OECMAKE
EXTRA_OECMAKE[doc] = "Additional cmake options."

  Additional CMake options. See the `cmake` class for additional information.

EXTRA_OECONF
EXTRA_OECONF[doc] = "Additional configure script options."

  Additional `configure` script options. See `PACKAGECONFIG_CONFARGS` for additional information on passing configure script options.

EXTRA_OEMAKE
EXTRA_OEMAKE[doc] = "Additional GNU make options."

  Additional GNU `make` options.

  Because the `EXTRA_OEMAKE` defaults to "", you need to set the variable to specify any required GNU options.

  `PARALLEL_MAKE` and `PARALLEL_MAKEINST` also make use of `EXTRA_OEMAKE` to pass the required flags.

EXTRA_OESCONS
EXTRA_OESCONS[doc] = "When a recipe inherits the scons class, this variable specifies additional configuration options you want to pass to the scons command line."

  When inheriting the `scons` class, this variable specifies additional configuration options you want to pass to the `scons` command line.

EXTRA_USERS_PARAMS
EXTRA_USERS_PARAMS[doc] = "When a recipe inherits the extrausers class, this variable provides image level user and group operations."

  When inheriting the `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` 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; \
           # "

### F

FEATURE_PACKAGES
FEATURE_PACKAGES[doc] = "Defines one or more packages to include in an image when a specific item is included in IMAGE_FEATURES. When setting the value, FEATURE_PACKAGES should have the name of the feature item as an override."

  Defines one or more packages to include in an image when a specific item is included in `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.

  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
FEED_DEPLOYDIR_BASE_URI[doc] = "Allow to serve ipk deploy directory as an ad hoc feed (bogofeed). Set to base URL of the directory as exported by HTTP. Set of ad hoc feed configs will be generated in the image."

  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
FILES[doc] = "The list of directories or files that are placed in a package."

  The list of files and directories that are placed in a package. The `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"

  ### Notes

  - When specifying files or paths, you can pattern match using Python's `glob` 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. 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` variable for information on how to identify these files to the PMS.

FILES_SOLIBSDEV
FILES_SOLIBSDEV[doc] = "Defines the full path name of the development symbolic link (symlink) for shared libraries on the target platform."

  Defines the file specification to match `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
FILESEXTRAPATHS[doc] = "Extends the search path the OpenEmbedded build system uses when looking for files and patches as it processes recipes and append files."

  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` 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.

  When extending `FILESEXTRAPATHS`, be sure to use the immediate expansion (`:=`) operator. Immediate expansion makes sure that BitBake evaluates `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`-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 in `meta-intel/common/recipes-kernel/linux`. Here, the machine override is a special `PACKAGE_ARCH` definition for multiple `meta-intel` machines.

  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
FILESOVERRIDES[doc] = "A subset of OVERRIDES used by the OpenEmbedded build system for creating FILESPATH."

  A subset of `OVERRIDES` used by the OpenEmbedded build system for creating `FILESPATH`. The `FILESOVERRIDES` variable uses overrides to automatically extend the `FILESPATH` variable. For an example of how that works, see the `FILESPATH` variable description. Additionally, you find more information on how overrides are handled in the "Conditional Syntax (Overrides)" section of the BitBake User Manual.

  By default, the `FILESOVERRIDES` variable is defined as:

           FILESOVERRIDES = "${TRANSLATED_TARGET_ARCH}:${MACHINEOVERRIDES}:${DISTROOVERRIDES}"

  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
FILESPATH[doc] = "The default set of directories the OpenEmbedded build system uses when searching for patches and files. It is defined in the base.bbclass class found in meta/classes in the Source Directory. Do not hand-edit the FILESPATH variable."

  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` statements.

  The default value for the `FILESPATH` variable is defined in the `base.bbclass` class found in `meta/classes` in the 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` variable.

  ### Notes

  - 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` 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` 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" section in the Yocto Project Overview and Concepts Manual and the "Patching Code" section in the Yocto Project Development Tasks Manual. See the `do_patch` task as well.

FILESYSTEM_PERMS_TABLES
FILESYSTEM_PERMS_TABLES[doc] = "Allows you to define your own file permissions settings table as part of your configuration for the packaging process."

  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. 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, 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` variable.

  For guidance on how to create your own file permissions settings table file, examine the existing `fs-perms.txt`.

FONT_EXTRA_RDEPENDS
FONT_EXTRA_RDEPENDS[doc] = "When a recipe inherits the fontcache class, this variable specifies runtime dependencies for font packages. This variable defaults to 'fontconfig-utils'."

  When inheriting the `fontcache` class, this variable specifies the runtime dependencies for font packages. By default, the `FONT_EXTRA_RDEPENDS` is set to "fontconfig-utils".

FONT_PACKAGES
FONT_PACKAGES[doc] = "When a recipe inherits the fontcache class, this variable identifies packages containing font files that need to be cached by Fontconfig."

  When inheriting the `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``}`). Use this variable if fonts you need are in a package other than that main package.

FORCE_RO_REMOVE
FORCE_RO_REMOVE[doc] = "Forces the removal of the packages listed in ROOTFS_RO_UNNEEDED during the generation of the root filesystem."

  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
FULL_OPTIMIZATION[doc]= "The options to pass in TARGET_CFLAGS and CFLAGS when compiling an optimized system. This variable defaults to '-fexpensive-optimizations -fomit-frame-pointer -frename-registers -O2'."

  The options to pass in `TARGET_CFLAGS` and `CFLAGS` when compiling an optimized system. This variable defaults to "-O2 -pipe ${DEBUG_FLAGS}".

### G

GCCPIE
GCCPIE[doc] = "Enables Position Independent Executables (PIE) within the GNU C Compiler (GCC)."

  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
GCCVERSION[doc] = "Specifies the default version of the GNU C Compiler (GCC) to use."

  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
GDB[doc] = "The minimal command and arguments to run the GNU Debugger."

  The minimal command and arguments to run the GNU Debugger.

GITDIR
GITDIR[doc] = "The directory where Git clones will be stored."

  The directory in which a local copy of a Git repository is stored when it is cloned.

GLIBC_GENERATE_LOCALES
GLIBC_GENERATE_LOCALES[doc]= "Specifies the list of GLIBC locales to generate should you not wish to generate all LIBC locals, which can be time consuming."

  Specifies the list of GLIBC locales to generate should you not wish to generate all LIBC locals, which can be time consuming.

  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
GROUPADD_PARAM[doc] = "When a recipe inherits the 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."

  When inheriting the `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 .
GROUPMEMS_PARAM
GROUPMEMS_PARAM[doc] = "When a recipe inherits the 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."

  When inheriting the `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 .

GRUB_GFXSERIAL
GRUB_GFXSERIAL[doc] = "Configures the GNU GRand Unified Bootloader (GRUB) to have graphics and serial in the boot menu."

  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` class for more information on how this variable is used.

GRUB_OPTS
GRUB_OPTS[doc] = "Additional options to add to the GNU GRand Unified Bootloader (GRUB) configuration."

  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` class for more information on how this variable is used.

GRUB_TIMEOUT
GRUB_TIMEOUT[doc] = "Specifies the timeout before executing the default LABEL in the GNU GRand Unified Bootloader (GRUB)."

  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` class for more information on how this variable is used.

GTKIMMODULES_PACKAGES
GTKIMMODULES_PACKAGES[doc] = "For recipes that inherit the 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."

  When inheriting the `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.

### H

HOMEPAGE
HOMEPAGE[doc] = "Website where more information about the software the recipe is building can be found."

  Website where more information about the software the recipe is building can be found.

HOST_ARCH
HOST_ARCH[doc] = "The name of the target architecture. Normally same as the TARGET_ARCH."

  The name of the target architecture, which is normally the same as `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
HOST_CC_ARCH[doc] = "The name of the host architecture. Normally same as the TARGET_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` 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
HOST_OS[doc] = "The name of the target operating system. Normally the same as the TARGET_OS."

  Specifies the name of the target operating system, which is normally the same as the `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
HOST_PREFIX[doc] = "The prefix for the cross compile toolchain. Normally same as the TARGET_PREFIX."

  Specifies the prefix for the cross-compile toolchain. `HOST_PREFIX` is normally the same as `TARGET_PREFIX`.

HOST_SYS
HOST_SYS[doc] = "Specifies the system, including the architecture and the operating system, for which the build is occurring in the context of the current recipe."

  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`, `HOST_VENDOR`, and `HOST_OS` variables.

  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
HOSTTOOLS[doc] = "A space-separated list (filter) of tools on the build host that should be allowed to be called from within build tasks."

  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`.

HOSTTOOLS_NONFATAL
HOSTTOOLS_NONFATAL[doc] = "A space-separated list (filter) of tools on the build host that should be allowed to be called from within build tasks."

  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`, 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
HOST_VENDOR[doc] = "The name of the vendor. Normally same as the TARGET_VENDOR."

  Specifies the name of the vendor. `HOST_VENDOR` is normally the same as `TARGET_VENDOR`.

### I

ICECC_DISABLED
ICECC_DISABLED[doc] = "Disables or enables the icecc (Icecream) function."

  Disables or enables the `icecc` (Icecream) function. For more information on this function and best practices for using this variable, see the "`icecc.bbclass`" 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
ICECC_ENV_EXEC[doc] = "Points to the icecc-create-env script that you provide."

  Points to the `icecc-create-env` script that you provide. This variable is used by the `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
ICECC_PARALLEL_MAKE[doc] = "Extra options passed to the make command during the do_compile task that specify parallel compilation."

  Extra options passed to the `make` command during the `do_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.

  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` 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
ICECC_PATH[doc] = "The location of the icecc binary."

  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` class attempts to define it by locating `icecc` using `which`.

ICECC_USER_CLASS_BL
ICECC_USER_CLASS_BL[doc] = "Identifies user classes that you do not want the Icecream distributed compile support to consider."

  Identifies user classes that you do not want the Icecream distributed compile support to consider. This variable is used by the `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
ICECC_USER_PACKAGE_BL[doc] = "Identifies user recipes that you do not want the Icecream distributed compile support to consider."

  Identifies user recipes that you do not want the Icecream distributed compile support to consider. This variable is used by the `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
ICECC_USER_PACKAGE_WL[doc] = "Identifies user recipes that use an empty PARALLEL_MAKE variable that you want to force remote distributed compilation on using the Icecream distributed compile support."

  Identifies user recipes that use an empty `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` class. You set this variable in your `local.conf` file.

IMAGE_BASENAME
IMAGE_BASENAME[doc] = "The base name of image output files."

  The base name of image output files. This variable defaults to the recipe name (`${``PN``}`).

IMAGE_BOOT_FILES
IMAGE_BOOT_FILES[doc] = "A space-separated list of files from ${DEPLOY_DIR_IMAGE} to place in boot partition."

  A space-separated list of files installed into the boot partition when preparing an image using the Wic tool with the `bootimg-partition` 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`. 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" section of the Yocto Project Development Tasks Manual. Reference material for Wic is located in the "OpenEmbedded Kickstart (.wks) Reference" chapter.

IMAGE_CLASSES
IMAGE_CLASSES[doc] = "A list of classes that all images should inherit."

  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.

IMAGE_CMD
IMAGE_CMD[doc] = "Specifies the command to create the image file for a specific image type, which corresponds to the value set set in IMAGE_FSTYPES, (e.g. ext3, btrfs, and so forth)."

  Specifies the command to create the image file for a specific image type, which corresponds to the value set set in `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` class file, which is `meta/classes/image_types.bbclass`.

IMAGE_DEVICE_TABLES
IMAGE_DEVICE_TABLES[doc] = "Specifies one or more files that contain custom device tables that are passed to the makedevs command as part of creating an image."

  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`. For details on how you should write device table files, see `meta/files/device_table-minimal.txt` as an example.

IMAGE_FEATURES
IMAGE_FEATURES[doc] = "The primary list of features to include in an image. Configure this variable in an image recipe."

  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, best practices dictate that you do not.

  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" 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`" section in the Yocto Project Development Tasks Manual.

IMAGE_FSTYPES
IMAGE_FSTYPES[doc] = "Formats of root filesystem images that you want to have created."

  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`.

  ### Notes

  - 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
IMAGE_INSTALL[doc] = "Used by recipes to specify the packages to install into an image through image.bbclass."

  Used by recipes to specify the packages to install into an image through the `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` 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.

  ### Caution

  - When working with a `core-image-minimal-initramfs` image, do not use the `IMAGE_INSTALL` variable to specify packages for installation. Instead, use the `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" section in the Yocto Project Development Tasks Manual.

  - Using `IMAGE_INSTALL` with the `+=` 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 `?=` 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
IMAGE_LINGUAS[doc] = "Specifies the list of locales to install into the image during the root filesystem construction process."

  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` variable for information on generating GLIBC locales.

IMAGE_MANIFEST
IMAGE_MANIFEST[doc] = "The manifest file for the image. This file lists all the installed packages that make up the image."

  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` 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` and `IMAGE_NAME` variables. You can find information on how the image is created in the "Image Generation" section in the Yocto Project Overview and Concepts Manual.
IMAGE_NAME
IMAGE_NAME[doc] = "The name of the output image files minus the extension."

  The name of the output image files minus the extension. This variable is derived using the `IMAGE_BASENAME`, `MACHINE`, and `DATETIME` variables:

           IMAGE_NAME = "${IMAGE_BASENAME}-${MACHINE}-${DATETIME}"

IMAGE_OVERHEAD_FACTOR
IMAGE_OVERHEAD_FACTOR[doc] = "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."

  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
IMAGE_PKGTYPE[doc] = "Defines the package type (i.e. DEB, RPM, IPK, or TAR) used by the OpenEmbedded build system."

  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`, `package_rpm`, `package_ipk`, or `package_tar` class.

  ### Warning

  The `package_tar` class is broken and is not supported. It is recommended that you do not use it.

  The `populate_sdk_*` and `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_*` class using the `PACKAGE_CLASSES` variable. The OpenEmbedded build system uses the first package type (e.g. DEB, RPM, or IPK) that appears with the variable

  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
IMAGE_POSTPROCESS_COMMAND[doc] = "Specifies a list of functions to call once the OpenEmbedded build system creates the final image output files."

  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` variable for more information.

IMAGE_PREPROCESS_COMMAND
IMAGE_PREPROCESS_COMMAND[doc] = "Specifies a list of functions to call before the OpenEmbedded build system creates the final image output files."

  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` variable for more information.

IMAGE_ROOTFS
IMAGE_ROOTFS[doc] = "The location of the root filesystem while it is under construction (i.e. during do_rootfs)."

  The location of the root filesystem while it is under construction (i.e. during the `do_rootfs` task). This variable is not configurable. Do not change it.

IMAGE_ROOTFS_ALIGNMENT
IMAGE_ROOTFS_ALIGNMENT[doc] = "Specifies the alignment for the output image file in Kbytes."

  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` for additional information.

IMAGE_ROOTFS_EXTRA_SPACE
IMAGE_ROOTFS_EXTRA_SPACE[doc] = "Defines additional free disk space created in the image in Kbytes. By default, this variable is set to '0'."

  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
IMAGE_ROOTFS_SIZE[doc] = "Defines the size in Kbytes for the generated image."

  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` and `IMAGE_ROOTFS_EXTRA_SPACE` variables for related information.

IMAGE_TYPEDEP
IMAGE_TYPEDEP[doc] = "Specifies a dependency from one image type on another."

  Specifies a dependency from one image type on another. Here is an example from the `image-live` class:

           IMAGE_TYPEDEP_live = "ext3"

  In the previous example, the variable ensures that when "live" is listed with the `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
IMAGE_TYPES[doc] = "Specifies the complete list of supported image types by default."

  Specifies the complete list of supported image types by default:

           btrfs
           container
           cpio
           cpio.gz
           cpio.lz4
           cpio.lzma
           cpio.xz
           cramfs
           elf
           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
           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.

INC_PR
INC_PR[doc] = "Helps define the recipe revision for recipes that share a common include file."

  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` 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
INCOMPATIBLE_LICENSE[doc] = "Specifies a space-separated list of license names (as they would appear in LICENSE) that should be excluded from the build."

  Specifies a space-separated list of license names (as they would appear in `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.

  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.
INHERIT
INHERIT[doc] = "Causes the named class or classes to be inherited globally."

  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" section in the Bitbake User Manual.

INHERIT_DISTRO
INHERIT_DISTRO[doc] = "Lists classes that will be inherited at the distribution level. It is unlikely that you want to edit this variable."

  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
INHIBIT_DEFAULT_DEPS[doc] = "Prevents the default dependencies, namely the C compiler and standard C library (libc), from being added to DEPENDS."

  Prevents the default dependencies, namely the C compiler and standard C library (libc), from being added to `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
INHIBIT_PACKAGE_DEBUG_SPLIT[doc] = "If set to "1", prevents the OpenEmbedded build system from splitting out debug information during packaging"

  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` task. For more information on how debug information is split out, see the `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
INHIBIT_PACKAGE_STRIP[doc] = "If set to "1", causes the build to not strip binaries in resulting packages."

  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``}-dbg`. Consequently, you should not set `INHIBIT_PACKAGE_STRIP` when you plan to debug in general.

INHIBIT_SYSROOT_STRIP
INHIBIT_SYSROOT_STRIP[doc] = "If set to "1", causes the build to not strip binaries in the resulting sysroot."

  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` class. This class uses a `sys_strip()` function to test for the variable and acts accordingly.

  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
INITRAMFS_FSTYPES[doc] = "Defines the format for the output image of an initial RAM filesystem (initramfs), which is used during boot."

  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` variable.

  The default value of this variable, which is set in the `meta/conf/bitbake.conf` configuration file in the Source Directory, is "cpio.gz". The Linux kernel's initramfs mechanism, as opposed to the initial RAM filesystem initrd mechanism, expects an optionally compressed cpio archive.

INITRAMFS_IMAGE
INITRAMFS_IMAGE[doc] = "Specifies the PROVIDES name of an image recipe that is used to build an initial RAM filesystem (initramfs) image."

  Specifies the `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` to `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).

  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` class, and the `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` 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" section in the Yocto Project Development Tasks Manual.

INITRAMFS_IMAGE_BUNDLE
INITRAMFS_IMAGE_BUNDLE[doc] = "Controls whether or not the image recipe specified by INITRAMFS_IMAGE is run through an extra pass (do_bundle_initramfs) during kernel compilation in order to build a single binary that contains both the kernel image and the initial RAM filesystem (initramfs)."

  Controls whether or not the image recipe specified by `INITRAMFS_IMAGE` is run through an extra pass (`do_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` kernel feature.

  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.

  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` class sets this variable to a null string as follows:

           INITRAMFS_IMAGE_BUNDLE ?= ""

  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` file for additional information. Also, for information on creating an initramfs, see the "Building an Initial RAM Filesystem (initramfs) Image" section in the Yocto Project Development Tasks Manual.
INITRAMFS_LINK_NAME
INITRAMFS_LINK_NAME[doc] = "The link name of the initial RAM filesystem image."

  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` variable for additional information.

INITRAMFS_NAME
INITRAMFS_NAME[doc] = "The base name of the initial RAM filesystem image."

  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` variable, which is set in the same file, has the following value:

           KERNEL_ARTIFACT_NAME ?= "${PKGE}-${PKGV}-${PKGR}-${MACHINE}${IMAGE_VERSION_SUFFIX}"

INITRD
INITRD[doc] = "Indicates a list of filesystem images to concatenate and use as an initial RAM disk (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` class.

INITRD_IMAGE
INITRD_IMAGE[doc] = "When building a "live" bootable image (i.e. when IMAGE_FSTYPES contains "live"), INITRD_IMAGE specifies the image recipe that should be built to provide the initial RAM disk image."

  When building a "live" bootable image (i.e. when `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` class for more information.

INITSCRIPT_NAME
INITSCRIPT_NAME[doc] = "The filename of the initialization script as installed to ${sysconfdir}/init.d."

  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
INITSCRIPT_PACKAGES[doc] = "A list of the packages that contain initscripts. This variable is used in recipes when using update-rc.d.bbclass. The variable is optional and defaults to the PN variable."

  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` variable.

INITSCRIPT_PARAMS
INITSCRIPT_PARAMS[doc] = "Specifies the options to pass to update-rc.d. The variable is mandatory and is used in recipes when using update-rc.d.bbclass."

  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` 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 .

INSANE_SKIP
INSANE_SKIP[doc] = "Specifies the QA checks to skip for a specific package within a recipe."

  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`" section for a list of the valid QA checks you can specify using this variable.

INSTALL_TIMEZONE_FILE
INSTALL_TIMEZONE_FILE[doc] = "Enables installation of the /etc/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
IPK_FEED_URIS[doc] = "List of ipkg feed records to put into generated image."

  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.

### K

KARCH
KARCH[doc] = "Defines the kernel architecture used when assembling the configuration. You define the KARCH variable in the BSP Descriptions."

  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.

KBRANCH
KBRANCH[doc] = "A regular expression used by the build process to explicitly identify the kernel branch that is validated, patched, and configured during a build."

  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"
           KBRANCH_mpc8315e-rdb = "standard/fsl-mpc8315e-rdb"

  The `KBRANCH` statements identify the kernel branch to use when building for each supported BSP.
KBUILD_DEFCONFIG
KBUILD_DEFCONFIG[doc] = "Specifies an "in-tree" kernel configuration file for use during a kernel build."

  When used with the `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` 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" section in the Yocto Project Linux Kernel Development Manual.
KERNEL_ALT_IMAGETYPE
KERNEL_ALT_IMAGETYPE[doc] = "Specifies an alternate kernel image type for creation."

  Specifies an alternate kernel image type for creation in addition to the kernel image type specified using the `KERNEL_IMAGETYPE` variable.

KERNEL_ARTIFACT_NAME
KERNEL_ARTIFACT_NAME[doc] = "Specifies the name of all of the build artifacts."

  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`, `PKGV`, `PKGR`, and `MACHINE` variables for additional information.

  The `IMAGE_VERSION_SUFFIX` variable is set to `DATETIME`.

KERNEL_CLASSES
KERNEL_CLASSES[doc] = "A list of classes defining kernel image types that kernel class should inherit."

  A list of classes defining kernel image types that the `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
KERNEL_DEVICETREE[doc] = "Specifies the name of the generated Linux kernel device tree (i.e. the .dtb) file."

  Specifies the name of the generated Linux kernel device tree (i.e. the `.dtb`) file.

  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` class must be inherited.
KERNEL_DTB_LINK_NAME
KERNEL_DTB_LINK_NAME[doc] = "The link name of the kernel device tree binary (DTB)."

  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` variable for additional information.

KERNEL_DTB_NAME
KERNEL_DTB_NAME[doc] = "The base name of the kernel device tree binary (DTB)."

  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` 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
KERNEL_EXTRA_ARGS[doc] = "Specifies additional make command-line arguments the OpenEmbedded build system passes on when compiling the kernel."

  Specifies additional `make` command-line arguments the OpenEmbedded build system passes on when compiling the kernel.

KERNEL_FEATURES
KERNEL_FEATURES[doc] = "Includes additional kernel metadata. The metadata you add through this variable includes config fragments and features descriptions."

  Includes additional kernel metadata. In the OpenEmbedded build system, the default Board Support Packages (BSPs) Metadata is provided through the `KMACHINE` and `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
KERNEL_FIT_LINK_NAME[doc] = "The link name of the kernel flattened image tree (FIT) image."

  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` variable for additional information.

KERNEL_FIT_NAME
KERNEL_FIT_NAME[doc] = "The base name of the kernel flattened image tree (FIT) image."

  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` 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
KERNEL_IMAGE_LINK_NAME[doc] = "The link name for the kernel image."

  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` variable for additional information.

KERNEL_IMAGE_MAXSIZE
KERNEL_IMAGE_MAXSIZE[doc] = "The maximum allowable size in kilobytes of the kernel image file."

  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` 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
KERNEL_IMAGE_NAME[doc] = "The base name of the kernel image."

  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` variable, which is set in the same file, has the following value:

           KERNEL_ARTIFACT_NAME ?= "${PKGE}-${PKGV}-${PKGR}-${MACHINE}${IMAGE_VERSION_SUFFIX}"

KERNEL_IMAGETYPE
KERNEL_IMAGETYPE[doc] = "The type of kernel to build for a device, usually set by the machine configuration files and defaults to 'zImage'."

  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` variable.

KERNEL_MODULE_AUTOLOAD
KERNEL_MODULE_AUTOLOAD[doc] = "Lists kernel modules that need to be auto-loaded during boot"

  Lists kernel modules that need to be auto-loaded during boot.

  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` variable.

KERNEL_MODULE_PROBECONF
KERNEL_MODULE_PROBECONF[doc] = "Lists kernel modules for which the build system expects to find module_conf_* values that specify configuration for each of the modules."

  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_*` variable.

KERNEL_PATH
KERNEL_PATH[doc] = "The location of the kernel sources. This variable is set to the value of the STAGING_KERNEL_DIR within the module class (module.bbclass)."

  The location of the kernel sources. This variable is set to the value of the `STAGING_KERNEL_DIR` within the `module` class. For information on how this variable is used, see the "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` 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
KERNEL_SRC[doc] = "The location of the kernel sources. This variable is set to the value of the STAGING_KERNEL_DIR within the module class (module.bbclass)."

  The location of the kernel sources. This variable is set to the value of the `STAGING_KERNEL_DIR` within the `module` class. For information on how this variable is used, see the "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` 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
KERNEL_VERSION[doc] = "Specifies the version of the kernel as extracted from version.h or utsrelease.h within the kernel sources."

  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
KERNELDEPMODDEPEND[doc] = "Specifies whether or not to use the data referenced through the PKGDATA_DIR directory."

  Specifies whether the data referenced through `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
KFEATURE_DESCRIPTION[doc] = "Provides a short description of a configuration fragment. You use this variable in the .scc file that describes a configuration fragment file."

  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
KMACHINE[doc] = "The machine as known by the kernel."

  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
KTYPE[doc] = "Defines the kernel type to be used in assembling the configuration."

  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" section in the Yocto Project Linux Kernel Development Manual for more information on kernel types.

  You define the `KTYPE` variable in the BSP Descriptions. The value you use must match the value used for the `LINUX_KERNEL_TYPE` value used by the kernel recipe.

### L

LABELS
LABELS[doc] = "Provides a list of targets for automatic configuration."

  Provides a list of targets for automatic configuration.

  See the `grub-efi` class for more information on how this variable is used.

LAYERDEPENDS
LAYERDEPENDS[doc] = "Lists the layers, separated by spaces, on which this recipe depends. This variable is used in the conf/layer.conf file and must be suffixed with the name of the specific layer."

  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``_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
LAYERDIR[doc] = "When used inside the layer.conf configuration file, this variable provides the path of the current layer."

  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
LAYERRECOMMENDS[doc] = "Lists the layers, separated by spaces, recommended for use with this layer."

  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
LAYERSERIES_COMPAT[doc] = "Lists the OpenEmbedded-Core versions for which a layer is compatible."

  Lists the versions of the OpenEmbedded-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 (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;"

  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" section in the Yocto Project Development Tasks Manual.

LAYERVERSION
LAYERVERSION[doc] = "Optionally specifies the version of a layer as a single number. This variable is used in the conf/layer.conf file and must be suffixed with the name of the specific layer."

  Optionally specifies the version of a layer as a single number. You can use this within `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
LD[doc] = "Minimal command and arguments to run the linker."

  The minimal command and arguments used to run the linker.

LDFLAGS
LDFLAGS[doc] = "Specifies the flags to pass to the linker."

  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` when building for the target

  - `BUILD_LDFLAGS` when building for the build host (i.e. `-native`)

  - `BUILDSDK_LDFLAGS` when building for an SDK (i.e. `nativesdk-`)

LEAD_SONAME
LEAD_SONAME[doc] = "Specifies the lead (or primary) compiled library file (i.e. .so) that the debian class applies its naming policy to given a recipe that packages multiple libraries."

  Specifies the lead (or primary) compiled library file (i.e. `.so`) that the `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
LIC_FILES_CHKSUM[doc] = "Checksums of the license text in the recipe source code."

  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` is set to "CLOSED").

  For more information, see the "Tracking License Changes" section in the Yocto Project Development Tasks Manual.

LICENSE
LICENSE[doc] = "The list of source licenses for the recipe. The logical operators &, '|', and parentheses can be used."

  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` 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
LICENSE_CREATE_PACKAGE[doc] = "Creates an extra package (i.e. ${PN}-lic) for each recipe and adds that package to the RRECOMMENDS+${PN}."

  Setting `LICENSE_CREATE_PACKAGE` to "1" causes the OpenEmbedded build system to create an extra package (i.e. `${``PN``}-lic`) for each recipe and to add those packages to the `RRECOMMENDS``_${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` variable of the recipe metadata and copies of files marked in `LIC_FILES_CHKSUM` as containing license text).

  For related information on providing license text, see the `COPY_LIC_DIRS` variable, the `COPY_LIC_MANIFEST` variable, and the "Providing License Text" section in the Yocto Project Development Tasks Manual.

LICENSE_FLAGS
LICENSE_FLAGS[doc] = "Specifies additional flags for a recipe you must whitelist through LICENSE_FLAGS_WHITELIST in order to allow the recipe to be built."

  Specifies additional flags for a recipe you must whitelist through `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` 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" section in the Yocto Project Development Tasks Manual.

LICENSE_FLAGS_WHITELIST
LICENSE_FLAGS_WHITELIST[doc] = "Lists license flags that when specified in LICENSE_FLAGS within a recipe should not prevent that recipe from being built."

  Lists license flags that when specified in `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" section in the Yocto Project Development Tasks Manual.

LICENSE_PATH
LICENSE_PATH[doc] = "Path to additional licenses used during the build."

  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
LINUX_KERNEL_TYPE[doc] = "Defines the kernel type to be used in assembling the configuration."

  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" 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`, the `LINUX_KERNEL_TYPE` variable defines the search arguments used by the kernel tools to find the appropriate description within the kernel Metadata with which to build out the sources and configuration.

LINUX_VERSION
LINUX_VERSION[doc] = "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."

  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` for the recipe:

           PV = "${LINUX_VERSION}+git${SRCPV}"

LINUX_VERSION_EXTENSION
LINUX_VERSION_EXTENSION[doc] = "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."

  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}"

  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
LOG_DIR[doc] = "Specifies the directory to which the OpenEmbedded build system writes overall log files. The default directory is ${TMPDIR}/log"

  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` variable.

### M

MACHINE
MACHINE[doc] = "Specifies the target device for which the image is built. You define MACHINE in the conf/local.conf file in the Build Directory."

  Specifies the target device for which the image is built. You define `MACHINE` in the `local.conf` file found in the 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 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 ?= "mpc8315e-rdb"
           MACHINE ?= "edgerouter"

  The last five are Yocto Project reference hardware boards, which are provided in the `meta-yocto-bsp` layer.

  Adding additional Board Support Package (BSP) layers to your configuration adds new possible settings for `MACHINE`.

MACHINE_ARCH
MACHINE_ARCH[doc] = "Specifies the name of the machine-specific architecture. This variable is set automatically from MACHINE or TUNE_PKGARCH."

  Specifies the name of the machine-specific architecture. This variable is set automatically from `MACHINE` or `TUNE_PKGARCH`. You should not hand-edit the `MACHINE_ARCH` variable.

MACHINE_ESSENTIAL_EXTRA_RDEPENDS
MACHINE_ESSENTIAL_EXTRA_RDEPENDS[doc] = "A list of required machine-specific packages to install as part of the image being built. Because this is a 'machine-essential' variable, the list of packages are essential for the machine to boot."

  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
MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS[doc] = "A list of recommended machine-specific packages to install as part of the image being built. Because this is a 'machine-essential' variable, the list of packages are essential for the machine to boot."

  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"

  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
MACHINE_EXTRA_RDEPENDS[doc] = "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."

  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
MACHINE_EXTRA_RRECOMMENDS[doc] = "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 dependencies on the packages in this list."

  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
MACHINE_FEATURES[doc] = "Specifies the list of hardware features the MACHINE supports."

  Specifies the list of hardware features the `MACHINE` is capable of supporting. For related information on enabling features, see the `DISTRO_FEATURES`, `COMBINED_FEATURES`, and `IMAGE_FEATURES` variables.

  For a list of hardware features supported by the Yocto Project as shipped, see the "Machine Features" section.

MACHINE_FEATURES_BACKFILL
MACHINE_FEATURES_BACKFILL[doc] = "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 and is not intended to be user-configurable."

  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" section for more information.

MACHINE_FEATURES_BACKFILL_CONSIDERED
MACHINE_FEATURES_BACKFILL_CONSIDERED[doc] = "Features from MACHINE_FEATURES_BACKFILL that should not be backfilled (i.e. added to MACHINE_FEATURES) during the build."

  Features from `MACHINE_FEATURES_BACKFILL` that should not be backfilled (i.e. added to `MACHINE_FEATURES`) during the build. See the "Feature Backfilling" section for more information.

MACHINEOVERRIDES
MACHINEOVERRIDES[doc] = "A colon-separated list of overrides that apply to the current machine."

  A colon-separated list of overrides that apply to the current machine. By default, this list includes the value of `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`.
MAINTAINER
MAINTAINER[doc] = "The email address of the distribution maintainer."

  The email address of the distribution maintainer.

MIRRORS
MIRRORS[doc] = "Specifies additional paths from which the OpenEmbedded build system gets source code."

  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` in that order.

  Assuming your distribution (`DISTRO`) is "poky", the default value for `MIRRORS` is defined in the `conf/distro/poky.conf` file in the `meta-poky` Git repository.

MLPREFIX
MLPREFIX[doc] = "Specifies a prefix has been added to PN to create a special version of a recipe or package (i.e. a Multilib version)."

  Specifies a prefix has been added to `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` variable). `MLPREFIX` gets set when a prefix has been added to `PN`.

  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` 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`, 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
module_autoload[doc] = "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."

  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` variable for more information.
module_conf
module_conf[doc] = "Specifies modprobe.d syntax lines for inclusion in the /etc/modprobe.d/modname.conf file."

  Specifies `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` 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` variable.

MODULE_TARBALL_DEPLOY
MODULE_TARBALL_DEPLOY[doc] = "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."

  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
MODULE_TARBALL_LINK_NAME[doc] = "The link name of the kernel module tarball."

  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` variable for additional information.

MODULE_TARBALL_NAME
MODULE_TARBALL_NAME[doc] = "The base name of the kernel module tarball."

  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` 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
MULTIMACH_TARGET_SYS[doc] = "Separates files for different machines such that you can build for multiple target machines using the same output directories."

  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`) modify the `MULTIMACH_TARGET_SYS` value.

  See the `STAMP` variable for an example. See the `STAGING_DIR_TARGET` variable for more information.

### N

NATIVELSBSTRING
NATIVELSBSTRING[doc] = "A string identifying the host distribution."

  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` if that variable is set.

NM
NM[doc] = "Minimal command and arguments to run 'nm'."

  The minimal command and arguments to run `nm`.

NO_GENERIC_LICENSE
NO_GENERIC_LICENSE[doc] = "Used to allow copying a license that does not exist in common licenses."

  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
NO_RECOMMENDATIONS[doc] = "When set to '1', no recommended packages will be installed. Some recommended packages might be required for certain system functionality, such as kernel-modules. It is up to the user to add packages to IMAGE_INSTALL as needed."

  Prevents installation of all "recommended-only" packages. Recommended-only packages are packages installed only through the `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` variable), the OpenEmbedded build system ignores your request and will install the packages to avoid dependency errors.

  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` and the `PACKAGE_EXCLUDE` variables for related information.

NOAUTOPACKAGEDEBUG
NOAUTOPACKAGEDEBUG[doc] = "Disables auto package from splitting .debug files."

  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"

### O

OBJCOPY
OBJCOPY[doc] = "Minimal command and arguments to run 'objcopy'."

  The minimal command and arguments to run `objcopy`.

OBJDUMP
OBJDUMP[doc] = "Minimal command and arguments to run 'objdump'."

  The minimal command and arguments to run `objdump`.

OE_BINCONFIG_EXTRA_MANGLE
OE_BINCONFIG_EXTRA_MANGLE[doc] = "When a recipe inherits the binconfig.bbclass class, this variable specifies additional arguments passed to the "sed" command."

  When inheriting the `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 for details on how this class applies these additional sed command arguments. For general information on the `binconfig` class, see the "`binconfig.bbclass`" section.

OE_IMPORTS
OE_IMPORTS[doc] = "An internal variable used to tell the OpenEmbedded build system what Python modules to import for every Python function run by the system."

  An internal variable used to tell the OpenEmbedded build system what Python modules to import for every Python function run by the system.

  Do not set this variable. It is for internal use only.

OE_INIT_ENV_SCRIPT
OE_INIT_ENV_SCRIPT[doc] = "The name of the build environment setup script for the purposes of setting up the environment within the extensible SDK."

  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
OE_TERMINAL[doc] = "Controls how the OpenEmbedded build system spawns interactive terminals on the host development system."

  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" 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
OEROOT[doc] = "The directory from which the top-level build environment setup script is sourced."

  The directory from which the top-level build environment setup script is sourced. The Yocto Project provides a top-level build environment setup script: `&OE_INIT_FILE;`. 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
OLDEST_KERNEL[doc] = "Declares the oldest version of the Linux kernel that the produced binaries must support."

  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
OVERRIDES[doc] = "A colon-separated list of overrides that currently apply."

  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)" section in the BitBake User Manual for more information on the overrides mechanism.

  The default value of `OVERRIDES` includes the values of the `CLASSOVERRIDE`, `MACHINEOVERRIDES`, and `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"

  ### Tip

  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

P
P[doc] = "The recipe name and version. P is comprised of ${PN}-${PV}."

  The recipe name and version. `P` is comprised of the following:

           ${PN}-${PV}

PACKAGE_ARCH
PACKAGE_ARCH[doc] = "The architecture of the resulting package or packages."

  The architecture of the resulting package or packages.

  By default, the value of this variable is set to `TUNE_PKGARCH` when building for the target, `BUILD_ARCH` when building for the build host, and "${SDK_ARCH}-${SDKPKGSUFFIX}" when building for the SDK.

  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` in the recipe as follows:

           PACKAGE_ARCH = "${MACHINE_ARCH}"

PACKAGE_ARCHS
PACKAGE_ARCHS[doc] = "A list of architectures compatible with the given target in order of priority."

  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
PACKAGE_BEFORE_PN[doc] = "Enables easily adding packages to PACKAGES before ${PN} so that the packages can pick up files that would normally be included in the default package."

  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
PACKAGE_CLASSES[doc] = "This variable specifies the package manager to use when packaging data. It is set in the conf/local.conf file in the Build Directory."

  This variable, which is set in the `local.conf` configuration file found in the `conf` folder of the 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"

  ### Warning

  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`" section.

PACKAGE_DEBUG_SPLIT_STYLE
PACKAGE_DEBUG_SPLIT_STYLE[doc] = "Determines how to split up the binary and debug information when creating *-dbg packages to be used with the GNU Project Debugger (GDB)."

  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" section in the Yocto Project Development Tasks Manual.

PACKAGE_EXCLUDE_COMPLEMENTARY
PACKAGE_EXCLUDE_COMPLEMENTARY[doc] = "Prevents specific packages from being installed when you are installing complementary packages."

  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` 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
PACKAGE_EXCLUDE[doc] = "Packages to exclude from the installation. If a listed package is required, an error is generated."

  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` 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` and the `BAD_RECOMMENDATIONS` variables for related information.

PACKAGE_EXTRA_ARCHS
PACKAGE_EXTRA_ARCHS[doc] = "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."

  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
PACKAGE_FEED_ARCHS[doc] = "Optionally specifies user-defined package architectures when constructing package feed URIs."

  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` and `PACKAGE_FEED_BASE_PATHS` variables.

  ### Tip

  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
PACKAGE_FEED_BASE_PATHS[doc] = "Specifies base path used when constructing package feed URIs."

  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` and `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
PACKAGE_FEED_URIS[doc] = "Specifies the front portion of the package feed URI used by the OpenEmbedded build system."

  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`, and `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_GROUP
PACKAGE_GROUP[doc] = "Defines one or more packages to include in an image when a specific item is included in IMAGE_FEATURES."

  The `PACKAGE_GROUP` variable has been renamed to `FEATURE_PACKAGES`. See the variable description for `FEATURE_PACKAGES` for information.

  If if you use the `PACKAGE_GROUP` variable, the OpenEmbedded build system issues a warning message.

PACKAGE_INSTALL
PACKAGE_INSTALL[doc] = "List of the packages to be installed into the image. The variable is generally not user-defined and uses IMAGE_INSTALL as part of the list."

  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` variable to specify packages for installation. The exception to this is when working with the `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" section in the Yocto Project Development Tasks Manual.

PACKAGE_INSTALL_ATTEMPTONLY
PACKAGE_INSTALL_ATTEMPTONLY[doc] = "List of packages attempted to be installed 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."

  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
PACKAGE_PREPROCESS_FUNCS[doc] = "Specifies a list of functions run to pre-process the PKGD directory prior to splitting the files out to individual packages."

  Specifies a list of functions run to pre-process the `PKGD` directory prior to splitting the files out to individual packages.

PACKAGE_WRITE_DEPS
PACKAGE_WRITE_DEPS[doc] = "Specifies post-installation and pre-installation script dependencies on native/cross tools."

  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" section in the Yocto Project Development Tasks Manual.

PACKAGECONFIG
PACKAGECONFIG[doc] = "This variable provides a means of enabling or disabling features of a recipe on a per-recipe basis."

  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:

           PACKAGECONFIG ??= "f1 f2 f3 ..."
           PACKAGECONFIG[f1] = "--with-f1,--without-f1,build-deps-f1,rt-deps-f1,rt-recs-f1"
           PACKAGECONFIG[f2] = "--with-f2,--without-f2,build-deps-f2,rt-deps-f2,rt-recs-f2"
           PACKAGECONFIG[f3] = "--with-f3,--without-f3,build-deps-f3,rt-deps-f3,rt-recs-f3"

  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 five 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` or `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`) that should be added if the feature is enabled.

  4. Additional runtime dependencies (`RDEPENDS`) that should be added if the feature is enabled.

  5. Additional runtime recommendations (`RRECOMMENDS`) that should be added if the feature is enabled.

  Consider the following `PACKAGECONFIG` block taken from the `librsvg` recipe. In this example the feature is `croco`, which has three arguments that determine the feature's behavior.

           PACKAGECONFIG ??= "croco"
           PACKAGECONFIG[croco] = "--with-croco,--without-croco,libcroco"

  The `--with-croco` and `libcroco` arguments apply only if the feature is enabled. In this case, `--with-croco` is added to the configure script argument list and `libcroco` 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-croco` is added to the configure script rather than `--with-croco`.

  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
PACKAGECONFIG_CONFARGS[doc] = "A space-separated list of configuration options generated from the PACKAGECONFIG setting."

  A space-separated list of configuration options generated from the `PACKAGECONFIG` setting.

  Classes such as `autotools` and `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
PACKAGEGROUP_DISABLE_COMPLEMENTARY[doc] = "Prevents automatic creation of the normal complementary packages such as -dev and -dbg in a packagegroup recipe."

  For recipes inheriting the `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
PACKAGES[doc] = "The list of packages the recipe creates."

  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` task goes through `PACKAGES` and uses the `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` task) are not generated, unless generation is forced through the `ALLOW_EMPTY` variable.

PACKAGES_DYNAMIC
PACKAGES_DYNAMIC[doc] = "A promise that your recipe satisfies runtime dependencies for optional modules that are found in other recipes."

  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`) 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` 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` (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" section in the Yocto Project Development Tasks Manual.

PACKAGESPLITFUNCS
PACKAGESPLITFUNCS[doc] = "Specifies a list of functions run to perform additional splitting of files into individual packages."

  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`, `FILES`, `RDEPENDS` and other packaging variables appropriately in order to perform the desired splitting.

PARALLEL_MAKE
PARALLEL_MAKE[doc] = "Specifies extra options that are passed to the make command during the compile tasks. This variable is usually in the form -j x, where x represents the maximum number of parallel threads make can run."

  Extra options passed to the `make` command during the `do_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.

  ### Caution

  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.

  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" section in the Yocto Project Development Tasks Manual.

PARALLEL_MAKEINST
PARALLEL_MAKEINST[doc] = "Extra options passed to the make install command during the do_install task in order to specify parallel installation."

  Extra options passed to the `make install` command during the `do_install` task in order to specify parallel installation. This variable defaults to the value of `PARALLEL_MAKE`.

  ### Notes and Cautions

  In order for `PARALLEL_MAKEINST` to be effective, `make` must be called with `${``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" section in the Yocto Project Development Tasks Manual.

PATCHRESOLVE
PATCHRESOLVE[doc] = "Enable or disable interactive patch resolution."

  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
PATCHTOOL[doc] = "Specifies the utility used to apply patches for a recipe during do_patch."

  Specifies the utility used to apply patches for a recipe during the `do_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
PE[doc] = "The epoch of the recipe. The default value is '0'. The field is used to make upgrades possible when the versioning scheme changes in some backwards incompatible way."

  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` variable.

PF
PF[doc] = "Specifies the recipe or package name and includes all version and revision numbers. This variable is comprised of ${PN}-${EXTENDPE}${PV}-${PR}."

  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:

           ${PN}-${EXTENDPE}${PV}-${PR}

PIXBUF_PACKAGES
PIXBUF_PACKAGES[doc] = "When a recipe inherits the pixbufcache class, this variable identifies packages that contain the pixbuf loaders used with gdk-pixbuf."

  When inheriting the `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``}`). Use this variable if the loaders you need are in a package other than that main package.

PKG
PKG[doc] = "The name of the resulting package created by the OpenEmbedded build system. When you use this variable, you must use a package name override."

  The name of the resulting package created by the OpenEmbedded build system.

  When using the `PKG` variable, you must use a package name override.

  For example, when the `debian` class renames the output package, it does so by setting `PKG_packagename`.

PKG_CONFIG_PATH
PKG_CONFIG_PATH[doc] = "Path to pkg-config files for the current build context."

  The path to `pkg-config` files for the current build context. `pkg-config` reads this variable from the environment.

PKGD
PKGD[doc] = "Points to the destination directory for files to be packaged before they are split into individual packages."

  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
PKGDATA_DIR[doc] = "Points to a shared, global-state directory that holds data generated during the packaging process."

  Points to a shared, global-state directory that holds data generated during the packaging process. During the packaging process, the `do_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" section in the Yocto Project Overview and Concepts Manual and the "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`.
PKGDEST
PKGDEST[doc] = "Points to the parent directory for files to be packaged after they have been split into individual packages."

  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`. Do not change this default.

PKGDESTWORK
PKGDESTWORK[doc] = "Points to a temporary work area where the do_package task saves package metadata."

  Points to a temporary work area where the `do_package` task saves package metadata. The `PKGDESTWORK` location defaults to the following:

           ${WORKDIR}/pkgdata

  Do not change this default.

  The `do_packagedata` task copies the package metadata from `PKGDESTWORK` to `PKGDATA_DIR` to make it available globally.

PKGE
PKGE[doc] = "The epoch of the package(s) built by the recipe."

  The epoch of the package(s) built by the recipe. By default, `PKGE` is set to `PE`.

PKGR
PKGR[doc] = "The revision of the package(s) built by the recipe."

  The revision of the package(s) built by the recipe. By default, `PKGR` is set to `PR`.

PKGV
PKGV[doc] = "The version of the package(s) built by the recipe."

  The version of the package(s) built by the recipe. By default, `PKGV` is set to `PV`.

PN
PN[doc] = "PN refers to a recipe name in the context of a file used by the OpenEmbedded build system as input to create a package.

  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
PNBLACKLIST[doc] = "Lists recipes you do not want the OpenEmbedded build system to build."

  Lists recipes you do not want the OpenEmbedded build system to build. This variable works in conjunction with the `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
POPULATE_SDK_POST_HOST_COMMAND[doc] = "Specifies a list of functions to call once the OpenEmbedded build system has created host part of the SDK."

  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` variable for more information.

POPULATE_SDK_POST_TARGET_COMMAND
POPULATE_SDK_POST_TARGET_COMMAND[doc] = "Specifies a list of functions to call once the OpenEmbedded build system has created target part of the SDK."

  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` variable for more information.

PR
PR[doc] = "The revision of the recipe. The default value for this variable is 'r0'."

  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` increases, `PR` is conventionally reset to "r0".

  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`, 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.

  `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" section in the Yocto Project Development Tasks Manual for more information.
PREFERRED_PROVIDER
PREFERRED_PROVIDER[doc] = "If multiple recipes provide an item, this variable determines which recipe should be given preference."

  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`). 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" section in the Yocto Project Development Tasks Manual.

  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
PREFERRED_VERSION[doc] = "If there are multiple versions of recipes available, this variable determines which recipe should be given preference."

  If multiple versions of recipes exist, this variable determines which version is given preference. You must always suffix the variable with the `PN` you want to select, and you should set the `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%"

  ### Important

  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`, 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` 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%"

  The `_forcevariable` override is not handled specially. This override only works because the default value of `OVERRIDES` includes "forcevariable".

PREMIRRORS
PREMIRRORS[doc] = "Specifies additional paths from which the OpenEmbedded build system gets source code."

  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` in that order.

  Assuming your distribution (`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:

           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
PRIORITY[doc] = "Indicates the importance of a package. The default value is 'optional'. Other standard values are 'required', 'standard', and 'extra'."

  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
PRIVATE_LIBS[doc] = "Specifies libraries installed within a recipe that should be ignored by the OpenEmbedded build system's shared library resolver."

  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" section in the Yocto Project Overview and Concepts Manual.

PROVIDES
PROVIDES[doc] = "A list of aliases that a recipe also provides. These aliases are useful for satisfying dependencies of other recipes during the build as specified by DEPENDS."

  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. If a recipe uses `PROVIDES`, the additional aliases are synonyms for the recipe and can be useful satisfying dependencies of other recipes during the build as specified by `DEPENDS`.

  Consider the following example `PROVIDES` statement from a recipe file `libav_0.8.11.bb`:

           PROVIDES += "libpostproc"

  The `PROVIDES` statement results in the "libav" recipe also being known as "libpostproc".

  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` variable is used to select which particular recipe provides a virtual target.

  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
PRSERV_HOST[doc] = "The network based PR service host and port."

  The network based `PR` service host and port.

  The `conf/local.conf.sample.extended` configuration file in the 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. You can set `PRSERV_HOST` to other values to use a remote PR service.
PTEST_ENABLED
PRSERV_HOST[doc] = "Specifies whether or not Package Test (ptest) functionality is enabled when building a recipe."

  Specifies whether or not Package Test (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`.

PV
PV[doc] = "The version of the recipe. The version is normally extracted from the recipe filename."

  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` variable.

PYTHON_ABI
PYTHON_ABI[doc] = "When used by recipes that inherit the distutils3, setuptools3, distutils, or setuptools classes, denotes the Application Binary Interface (ABI) currently in use for Python."

  When used by recipes that inherit the `distutils3`, `setuptools3`, `distutils`, or `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
PYTHON_PN[doc] = "When used by recipes that inherit the distutils3, setuptools3, distutils, or setuptools classes, specifies the major Python version being built."

  When used by recipes that inherit the `distutils3`, `setuptools3`, `distutils`, or `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`.

### R

RANLIB
RANLIB[doc] = "Minimal command and arguments to run 'ranlib'."

  The minimal command and arguments to run `ranlib`.

RCONFLICTS
RCONFLICTS[doc] = "The list of packages that conflict with another package. Note that the package will not be installed if the conflicting packages are not first removed."

  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
RDEPENDS[doc] = "Lists runtime dependencies of a package."

  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" 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_*` tasks. Exactly how this is done depends on which package format is used, which is determined by `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` (not to be confused with `do_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` 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.

  ### Caution

  `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` variable allows a different name to be used for the final package (e.g. the `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.

  ### Tip

  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` variable. You can also see the "Tasks" and "Dependencies" sections in the BitBake User Manual for additional information on tasks and dependencies.

REQUIRED_DISTRO_FEATURES
REQUIRED_DISTRO_FEATURES[doc] = "When a recipe inherits the 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."

  When inheriting the `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
RM_WORK_EXCLUDE[doc] = "With rm_work enabled, this variable specifies a list of packages whose work directories should not be removed."

  With `rm_work` enabled, this variable specifies a list of recipes whose work directories should not be removed. See the "`rm_work.bbclass`" section for more details.

ROOT_HOME
ROOT_HOME[doc] = "Defines the root home directory."

  Defines the root home directory. By default, this directory is set as follows in the BitBake configuration file:

           ROOT_HOME ??= "/home/root"

  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
ROOTFS[doc] = "Indicates a filesystem image to include as the root filesystem."

  Indicates a filesystem image to include as the root filesystem.

  The `ROOTFS` variable is an optional variable used with the `image-live` class.

ROOTFS_POSTINSTALL_COMMAND
ROOTFS_POSTINSTALL_COMMAND[doc] = "Specifies a list of functions to call after installing packages."

  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` variable for more information.

ROOTFS_POSTPROCESS_COMMAND
ROOTFS_POSTPROCESS_COMMAND[doc] = "Specifies a list of functions to call once the OpenEmbedded build system has created the root filesystem."

  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` variable for more information.

ROOTFS_POSTUNINSTALL_COMMAND
ROOTFS_POSTUNINSTALL_COMMAND[doc] = "Specifies a list of functions to call after removal of unneeded packages."

  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` variable for more information.

ROOTFS_PREPROCESS_COMMAND
ROOTFS_PREPROCESS_COMMAND[doc] = "Specifies a list of functions to call before the OpenEmbedded build system has created the root filesystem."

  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` variable for more information.

RPROVIDES
RPROVIDES[doc] = "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."

  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`).

  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
RRECOMMENDS[doc] = "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 needs them for the extended usability."

  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`, `NO_RECOMMENDATIONS`, and `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` or `PACKAGES_DYNAMIC` variables or the `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
RREPLACES[doc] = "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."

  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
RSUGGESTS[doc] = "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."

  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

S
S[doc] = "The location in the Build Directory where unpacked package source code resides."

  The location in the Build Directory where unpacked recipe source code resides. By default, this directory is `${``WORKDIR``}/${``BPN``}-${``PV``}`, where `${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 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`. 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
SANITY_REQUIRED_UTILITIES[doc] = "Specifies a list of command-line utilities that should be checked for during the initial sanity checking process when running BitBake."

  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
SANITY_TESTED_DISTROS[doc] = "A list of the host distribution identifiers that the build system has been tested against."

  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` 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
SDK_ARCH[doc] = "The target architecture for the SDK."

  The target architecture for the SDK. Typically, you do not directly set this variable. Instead, use `SDKMACHINE`.

SDK_DEPLOY
SDK_DEPLOY[doc] = "The directory set up and used by the populate_sdk_base to which the SDK is deployed."

  The directory set up and used by the `populate_sdk_base` class to which the SDK is deployed. The `populate_sdk_base` class defines `SDK_DEPLOY` as follows:

           SDK_DEPLOY = "${TMPDIR}/deploy/sdk"

SDK_DIR
SDK_DIR[doc] = "The parent directory used by the OpenEmbedded build system when creating SDK output."

  The parent directory used by the OpenEmbedded build system when creating SDK output. The `populate_sdk_base` class defines the variable as follows:

           SDK_DIR = "${WORKDIR}/sdk"

  The `SDK_DIR` directory is a temporary directory as it is part of `WORKDIR`. The final output directory is `SDK_DEPLOY`.

SDK_EXT_TYPE
SDK_EXT_TYPE[doc] = "Controls whether or not shared state artifacts are copied into the extensible SDK."

  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.

  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
SDK_HOST_MANIFEST[doc] = "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 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` class defines the manifest file as follows:

           SDK_HOST_MANIFEST = "${SDK_DEPLOY}/${TOOLCHAIN_OUTPUTNAME}.host.manifest"

  The location is derived using the `SDK_DEPLOY` and `TOOLCHAIN_OUTPUTNAME` variables.
SDK_INCLUDE_PKGDATA
SDK_INCLUDE_PKGDATA[doc] = "When set to "1", specifies to include the packagedata for all recipes in the "world" target in the extensible SDK."

  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.

  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
SDK_INCLUDE_TOOLCHAIN[doc] = "When set to "1", specifies to include the toolchain in the extensible SDK."

  When set to "1", specifies to include the toolchain in the extensible SDK. Including the toolchain is useful particularly when `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
SDK_INHERIT_BLACKLIST[doc] = "A list of classes to remove from the INHERIT value globally within the extensible SDK configuration."

  A list of classes to remove from the `INHERIT` value globally within the extensible SDK configuration. The `populate-sdk-ext` 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" section in the Yocto Project Application Development and the Extensible Software Development Kit (eSDK) manual.

SDK_LOCAL_CONF_BLACKLIST
SDK_LOCAL_CONF_BLACKLIST[doc] = "A list of variables not allowed through from the build system configuration into the extensible SDK configuration."

  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` class and excludes the following variables:

           CONF_VERSION
           BB_NUMBER_THREADS
           BB_NUMBER_PARSE_THREADS
           PARALLEL_MAKE
           PRSERV_HOST
           SSTATE_MIRRORS
           DL_DIR
           SSTATE_DIR
           TMPDIR
           BB_SERVER_TIMEOUT

  For additional information on how to customize the extensible SDK's configuration, see the "Configuring the Extensible SDK" section in the Yocto Project Application Development and the Extensible Software Development Kit (eSDK) manual.

SDK_LOCAL_CONF_WHITELIST
SDK_LOCAL_CONF_WHITELIST[doc] = "A list of variables allowed through from the build system configuration into the extensible SDK configuration."

  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` class.

  This list overrides the variables specified using the `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" section in the Yocto Project Application Development and the Extensible Software Development Kit (eSDK) manual.

SDK_NAME
SDK_NAME[doc] = "The base name for SDK output files."

  The base name for SDK output files. The name is derived from the `DISTRO`, `TCLIBC`, `SDK_ARCH`, `IMAGE_BASENAME`, and `TUNE_PKGARCH` variables:

           SDK_NAME = "${DISTRO}-${TCLIBC}-${SDK_ARCH}-${IMAGE_BASENAME}-${TUNE_PKGARCH}"

SDK_OS
SDK_OS[doc] = "The operating system for which the SDK will be built."

  Specifies the operating system for which the SDK will be built. The default value is the value of `BUILD_OS`.

SDK_OUTPUT
SDK_OUTPUT[doc] = "The location used by the OpenEmbedded build system when creating SDK output."

  The location used by the OpenEmbedded build system when creating SDK output. The `populate_sdk_base` class defines the variable as follows:

           SDK_DIR = "${WORKDIR}/sdk"
           SDK_OUTPUT = "${SDK_DIR}/image"
           SDK_DEPLOY = "${DEPLOY_DIR}/sdk"

  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
SDK_PACKAGE_ARCHS[doc] = "Specifies a list of architectures compatible with the SDK machine. This variable is set automatically and should not normally be hand-edited."

  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
SDK_POSTPROCESS_COMMAND[doc] = "Specifies a list of functions to call once the OpenEmbedded build system creates the SDK."

  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` variable for more information.

SDK_PREFIX
SDK_PREFIX[doc] = "The toolchain binary prefix used for nativesdk recipes."

  The toolchain binary prefix used for `nativesdk` recipes. The OpenEmbedded build system uses the `SDK_PREFIX` value to set the `TARGET_PREFIX` when building `nativesdk` recipes. The default value is "${SDK_SYS}-".

SDK_RECRDEP_TASKS
SDK_RECRDEP_TASKS[doc] = "A list of shared state tasks added to the extensible SDK."

  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`).
SDK_SYS
SDK_SYS[doc] = "Specifies the system, including the architecture and the operating system, for which the SDK will be built."

  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`, `SDK_VENDOR`, and `SDK_OS`. You do not need to set the `SDK_SYS` variable yourself.

SDK_TARGET_MANIFEST
SDK_TARGET_MANIFEST[doc] = "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 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` class defines the manifest file as follows:

           SDK_TARGET_MANIFEST = "${SDK_DEPLOY}/${TOOLCHAIN_OUTPUTNAME}.target.manifest"

  The location is derived using the `SDK_DEPLOY` and `TOOLCHAIN_OUTPUTNAME` variables.
SDK_TARGETS
SDK_TARGETS[doc] = "A list of targets to install from shared state as part of the standard or extensible SDK installation."

  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
SDK_TITLE[doc] = "The title to be printed when running the SDK installer."

  The title to be printed when running the SDK installer. By default, this title is based on the `DISTRO_NAME` or `DISTRO` variable and is set in the `populate_sdk_base` 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" section in the Yocto Project Application Development and the Extensible Software Development Kit (eSDK) manual.

SDK_UPDATE_URL
SDK_UPDATE_URL[doc] = "An optional URL for an update server for the extensible SDK."

  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
SDK_VENDOR[doc] = "Specifies the name of the SDK vendor."

  Specifies the name of the SDK vendor.

SDK_VERSION
SDK_VERSION[doc] = "Specifies the version for the SDK."

  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` and `DATE` variables.

SDKEXTPATH
SDKEXTPATH[doc] = "The default installation directory for the extensible SDK."

  The default installation directory for the Extensible SDK. By default, this directory is based on the `DISTRO` variable and is set in the `populate_sdk_base` 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" section in the Yocto Project Application Development and the Extensible Software Development Kit (eSDK) manual.

SDKIMAGE_FEATURES
SDKIMAGE_FEATURES[doc] = "Equivalent to IMAGE_FEATURES. However, this variable applies to the SDK generated from an image using the command 'bitbake -c populate_sdk imagename'."

  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
SDKMACHINE[doc] = "Specifies the architecture (i.e. i686 or x86_64) for which to build SDK items."

  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"

  You cannot set the `SDKMACHINE` variable in your distribution configuration file. If you do, the configuration will not take affect.

SDKPATH
SDKPATH[doc] = "Defines the path offered to the user for installation of the SDK that is generated by the OpenEmbedded build system."

  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
SDKTARGETSYSROOT[doc] = "Full path to the sysroot used for cross-compilation within an SDK as it will be when installed into the default SDKPATH."

  The full path to the sysroot used for cross-compilation within an SDK as it will be when installed into the default `SDKPATH`.

SECTION
SECTION[doc] = "The section in which packages should be categorized. Package management utilities can make use of this variable."

  The section in which packages should be categorized. Package management utilities can make use of this variable.

SELECTED_OPTIMIZATION
SELECTED_OPTIMIZATION[doc] = "The variable takes the value of FULL_OPTIMIZATION unless DEBUG_BUILD = '1'. In this case, the value of DEBUG_OPTIMIZATION is used."

  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` 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
SERIAL_CONSOLE[doc] = "Defines the serial consoles (TTYs) to enable using getty."

  Defines a serial console (TTY) to enable using getty. 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"

  The `SERIAL_CONSOLE` variable is deprecated. Please use the `SERIAL_CONSOLES` variable.

SERIAL_CONSOLES
SERIAL_CONSOLES[doc] = "Defines the serial consoles (TTYs) to enable using getty."

  Defines a serial console (TTY) to enable using getty. 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
SERIAL_CONSOLES_CHECK[doc] = "Selected SERIAL_CONSOLES to check against /proc/console before enabling using getty. Supported only by SysVinit."

  Specifies serial consoles, which must be listed in `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
SIGGEN_EXCLUDE_SAFE_RECIPE_DEPS[doc] = "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."

  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.

  ### Caution

  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
SIGGEN_EXCLUDERECIPES_ABISAFE[doc] = "A list of recipes that are completely stable and will never change."

  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.

  ### Caution

  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
SITEINFO_BITS[doc] = "Specifies the number of bits for the target system CPU."

  Specifies the number of bits for the target system CPU. The value should be either "32" or "64".

SITEINFO_ENDIANNESS
SITEINFO_ENDIANNESS[doc] = "Specifies the endian byte order of the target system. The value should be either 'le' for 'little-endian' or 'be' for 'big-endian'."

  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
SKIP_FILEDEPS[doc] = "Enables you to remove all files from the "Provides" section of an RPM package."

  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.

           SKIP_FILEDEPS = "1"

SOC_FAMILY
SOC_FAMILY[doc] = "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."

  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.

  You must include `conf/machine/include/soc-family.inc` for this variable to appear in `MACHINEOVERRIDES`.

SOLIBS
SOLIBS[doc] = "Defines the suffix for shared libraries used on the target platform."

  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
SOLIBSDEV[doc] = "Defines the suffix for the development symbolic link (symlink) for shared libraries on the target platform."

  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
SOURCE_MIRROR_FETCH[doc] = "Set as part of a source mirror generation script to skip COMPATIBLE_MACHINE and COMPATIBLE_HOST checks."

  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` variable and `COMPATIBLE_HOST` variables specify compatibility with a machine other than that of the current machine or host.

  ### Warning

  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
SOURCE_MIRROR_URL[doc] = "URL to source mirror that will be used before fetching from original SRC_URI."

  Defines your own `PREMIRRORS` from which to first fetch source before attempting to fetch from the upstream specified in `SRC_URI`.

  To use this variable, you must globally inherit the `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"

  You can specify only a single URL in `SOURCE_MIRROR_URL`.

SPDXLICENSEMAP
SPDXLICENSEMAP[doc] = "Maps commonly used license names to their SPDX counterparts found in meta/files/common-licenses/."

  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` variable.

SPECIAL_PKGSUFFIX
SPECIAL_PKGSUFFIX[doc] = "A list of prefixes for 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 variable."

  A list of prefixes for `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` variable.

SPL_BINARY
SPL_BINARY[doc] = "The file type of the Secondary Program Loader (SPL)."

  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" section in the Yocto Project Board Support Package Developer's Guide for additional information.

SRC_URI
SRC_URI[doc] = "The list of source files - local or remote. This variable tells the OpenEmbedded build system what bits to pull in for the build and how to pull them in."

  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" section in the BitBake User Manual.

  - `file://` - Fetches files, which are usually files shipped with the Metadata, from the local machine (e.g. patch files). The path is relative to the `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.

    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``}`.

  Here are options specific to recipes building code from a revision control system:

  - `mindate` - Apply the patch only if `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` 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
SRC_URI_OVERRIDES_PACKAGE_ARCH[doc] = "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."

  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
SRCDATE[doc] = "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)."

  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
SRCPV[doc] = "Returns the version string of the current package. This string is used to help define the value of PV."

  Returns the version string of the current package. This string is used to help define the value of `PV`.

  The `SRCPV` variable is defined in the `meta/conf/bitbake.conf` configuration file in the 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
SRCREV[doc] = "The revision of the source code used to build the package. This variable applies to Subversion, Git, Mercurial, and Bazaar only."

  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.

  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
SSTATE_DIR[doc] = "The directory for the shared state cache."

  The directory for the shared state cache.

SSTATE_MIRROR_ALLOW_NETWORK
SSTATE_MIRROR_ALLOW_NETWORK[doc] = "If set to "1", allows fetches from mirrors that are specified in SSTATE_MIRRORS to work even when fetching from the network is disabled by setting BB_NO_NETWORK to "1"."

  If set to "1", allows fetches from mirrors that are specified in `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
SSTATE_MIRRORS[doc] = "Configures the OpenEmbedded build system to search other mirror locations for prebuilt cache data objects before building out the data. You can specify a filesystem directory or a remote URL such as HTTP or FTP."

  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` and `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_MIRROR` with a regular expression that maps local search paths to server paths. The paths need to take into account `NATIVELSBSTRING` set by the `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`, 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
SSTATE_SCAN_FILES[doc] = "Controls the list of files the OpenEmbedded build system scans for hardcoded installation paths."

  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` class specifies the default list of files.

  For details on the process, see the `staging` class.

STAGING_BASE_LIBDIR_NATIVE
STAGING_BASE_LIBDIR_NATIVE[doc] = "Specifies the path to the /lib subdirectory of the sysroot directory for the build host."

  Specifies the path to the `/lib` subdirectory of the sysroot directory for the build host.

STAGING_BASELIBDIR
STAGING_BASELIBDIR[doc] = "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)."

  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`).

STAGING_BINDIR
STAGING_BINDIR[doc] = "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)."

  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`).

STAGING_BINDIR_CROSS
STAGING_BINDIR_CROSS[doc] = "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."

  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.

  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
STAGING_BINDIR_NATIVE[doc] = "Specifies the path to the /usr/bin subdirectory of the sysroot directory for the build host."

  Specifies the path to the `/usr/bin` subdirectory of the sysroot directory for the build host.

STAGING_DATADIR
STAGING_DATADIR[doc] = "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)."

  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`).

STAGING_DATADIR_NATIVE
STAGING_DATADIR_NATIVE[doc] = "Specifies the path to the /usr/share subdirectory of the sysroot directory for the build host."

  Specifies the path to the `/usr/share` subdirectory of the sysroot directory for the build host.

STAGING_DIR
STAGING_DIR[doc] = "Helps construct the recipe-sysroots directory, which is used during packaging."

  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` task, the "Sharing Files Between Recipes" section in the Yocto Project Development Tasks Manual, the "Configuration, Compilation, and Staging" section in the Yocto Project Overview and Concepts Manual, and the `SYSROOT_DIRS` variable.

  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
STAGING_DIR_HOST[doc] = "Specifies the path to the sysroot directory for the system that the component is built to run on."

  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` task copies files. Exceptions include `-native` recipes, where the `do_populate_sysroot` task instead uses `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 "${STAGING_DIR}/${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.

    `-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` and `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`, `do_compile`, and `do_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
STAGING_DIR_NATIVE[doc] = "Specifies the path to the sysroot directory used when building components that run on the build host itself."

  Specifies the path to the sysroot directory used when building components that run on the build host itself.

STAGING_DIR_TARGET
STAGING_DIR_TARGET[doc] = "Specifies the path to the sysroot used for the system for which the component generates code."

  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`.

  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
STAGING_ETCDIR_NATIVE[doc] = "Specifies the path to the /etc subdirectory of the sysroot directory for the build host."

  Specifies the path to the `/etc` subdirectory of the sysroot directory for the build host.

STAGING_EXECPREFIXDIR
STAGING_EXECPREFIXDIR[doc] = "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)."

  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`).

STAGING_INCDIR
STAGING_INCDIR[doc] = "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)."

  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`).

STAGING_INCDIR_NATIVE
STAGING_INCDIR_NATIVE[doc] = "Specifies the path to the /usr/include subdirectory of the sysroot directory for the build host."

  Specifies the path to the `/usr/include` subdirectory of the sysroot directory for the build host.

STAGING_KERNEL_BUILDDIR
STAGING_KERNEL_BUILDDIR[doc] = "Points to the directory containing the kernel build artifacts."

  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
STAGING_KERNEL_DIR[doc] = "The directory with kernel headers that are required to build out-of-tree modules."

  The directory with kernel headers that are required to build out-of-tree modules.

STAGING_LIBDIR
STAGING_LIBDIR[doc] = "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)."

  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`).

STAGING_LIBDIR_NATIVE
STAGING_LIBDIR_NATIVE[doc] = "Specifies the path to the /usr/lib subdirectory of the sysroot directory for the build host."

  Specifies the path to the `/usr/lib` subdirectory of the sysroot directory for the build host.

STAMP
STAMP[doc] = "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."

  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" section in the Yocto Project Overview and Concepts Manual.

  See `STAMPS_DIR`, `MULTIMACH_TARGET_SYS`, `PN`, `EXTENDPE`, `PV`, and `PR` for related variable information.

STAMPS_DIR
STAMPS_DIR[doc] = "Specifies the base directory in which the OpenEmbedded build system places stamps."

  Specifies the base directory in which the OpenEmbedded build system places stamps. The default directory is `${TMPDIR}/stamps`.

STRIP
STRIP[doc] = "Minimal command and arguments to run 'strip' (strip symbols)."

  The minimal command and arguments to run `strip`, which is used to strip symbols.

SUMMARY
SUMMARY[doc] = "The short (80 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 variable if DESCRIPTION is not set in the recipe."

  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` variable if `DESCRIPTION` is not set in the recipe.

SVNDIR
SVNDIR[doc] = "The directory where Subversion checkouts are stored."

  The directory in which files checked out of a Subversion system are stored.

SYSLINUX_DEFAULT_CONSOLE
SYSLINUX_DEFAULT_CONSOLE[doc] = "Specifies the kernel boot 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` class initially sets this variable to null but then checks for a value later.

SYSLINUX_OPTS
SYSLINUX_OPTS[doc] = "Lists additional options to add to the syslinux file."

  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` class uses this variable to create a set of options.

SYSLINUX_SERIAL
SYSLINUX_SERIAL[doc] = "Specifies the alternate serial port or turns it off."

  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` class as follows:

           SYSLINUX_SERIAL ?= "0 115200"

  The class checks for and uses the variable as needed.

SYSLINUX_SPLASH
SYSLINUX_SPLASH[doc] = "An .LSS file used as the background for the VGA boot menu when you use the boot menu."

  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` class checks for this variable and if found, the OpenEmbedded build system installs the splash screen.

SYSLINUX_SERIAL_TTY
SYSLINUX_SERIAL_TTY[doc] = "Specifies the alternate console=tty... kernel boot argument."

  Specifies the alternate console=tty... kernel boot argument. The variable's default value is set in the `syslinux` class as follows:

           SYSLINUX_SERIAL_TTY ?= "console=ttyS0,115200"

  The class checks for and uses the variable as needed.

SYSROOT_DESTDIR
SYSROOT_DESTDIR[doc] = "Points to the temporary work directory (default ${WORKDIR}/sysroot-destdir) where the files populated into the sysroot are assembled during the do_populate_sysroot task."

  Points to the temporary directory under the work directory (default "`${``WORKDIR``}/sysroot-destdir`") where the files populated into the sysroot are assembled during the `do_populate_sysroot` task.

SYSROOT_DIRS
SYSROOT_DIRS[doc] = "Directories that are staged into the sysroot by the do_populate_sysroot task."

  Directories that are staged into the sysroot by the `do_populate_sysroot` task. By default, the following directories are staged:

           SYSROOT_DIRS = " \
               ${includedir} \
               ${libdir} \
               ${base_libdir} \
               ${nonarch_base_libdir} \
               ${datadir} \
           "

SYSROOT_DIRS_BLACKLIST
SYSROOT_DIRS_BLACKLIST[doc] = "Directories that are not staged into the sysroot by the do_populate_sysroot task."

  Directories that are not staged into the sysroot by the `do_populate_sysroot` task. You can use this variable to exclude certain subdirectories of directories listed in `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
SYSROOT_DIRS_NATIVE[doc] = "Extra directories staged into the sysroot by the do_populate_sysroot task for -native recipes, in addition to those specified in SYSROOT_DIRS."

  Extra directories staged into the sysroot by the `do_populate_sysroot` task for `-native` recipes, in addition to those specified in `SYSROOT_DIRS`. By default, the following extra directories are staged:

           SYSROOT_DIRS_NATIVE = " \
               ${bindir} \
               ${sbindir} \
               ${base_bindir} \
               ${base_sbindir} \
               ${libexecdir} \
               ${sysconfdir} \
               ${localstatedir} \
           "

  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
SYSROOT_PREPROCESS_FUNCS[doc] = "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."

  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
SYSTEMD_AUTO_ENABLE[doc] = "For recipes that inherit the systemd class, this variable specifies whether the specified service in SYSTEMD_SERVICE should start automatically or not."

  When inheriting the `systemd` class, this variable specifies whether the specified service in `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` class as follows:

           SYSTEMD_AUTO_ENABLE ??= "enable"

  You can disable the service by setting the variable to "disable".

SYSTEMD_BOOT_CFG
SYSTEMD_BOOT_CFG[doc] = "When EFI_PROVIDER is set to "systemd-boot", the SYSTEMD_BOOT_CFG variable specifies the configuration file that should be used."

  When `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` class sets the `SYSTEMD_BOOT_CFG` as follows:

           SYSTEMD_BOOT_CFG ?= "${S}/loader.conf"

  For information on Systemd-boot, see the Systemd-boot documentation.

SYSTEMD_BOOT_ENTRIES
SYSTEMD_BOOT_ENTRIES[doc] = "When 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."

  When `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` class sets the `SYSTEMD_BOOT_ENTRIES` as follows:

           SYSTEMD_BOOT_ENTRIES ?= ""

  For information on Systemd-boot, see the Systemd-boot documentation.

SYSTEMD_BOOT_TIMEOUT
SYSTEMD_BOOT_TIMEOUT[doc] = "When EFI_PROVIDER is set to "systemd-boot", the SYSTEMD_BOOT_TIMEOUT variable specifies the boot menu timeout in seconds."

  When `EFI_PROVIDER` is set to "systemd-boot", the `SYSTEMD_BOOT_TIMEOUT` variable specifies the boot menu timeout in seconds. By default, the `systemd-boot` class sets the `SYSTEMD_BOOT_TIMEOUT` as follows:

           SYSTEMD_BOOT_TIMEOUT ?= "10"

  For information on Systemd-boot, see the Systemd-boot documentation.

SYSTEMD_PACKAGES
SYSTEMD_PACKAGES[doc] = "For recipes that inherit the systemd class, this variable locates the systemd unit files when they are not found in the main recipe's package."

  When inheriting the `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
SYSTEMD_SERVICE[doc] = "For recipes that inherit the systemd class, this variable specifies the systemd service name for a package."

  When inheriting the `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
SYSVINIT_ENABLED_GETTYS[doc] = "Specifies which virtual terminals should run a getty, the default is '1'."

  When using SysVinit, specifies a space-separated list of the virtual terminals that should run a getty (allowing login), assuming `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

T
T[doc] = "This variable points to a directory were BitBake places temporary files, which consist mostly of task logs and scripts, when building a particular recipe."

  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` 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` variable, which points to the root of the directory tree where BitBake places the output of an entire build.

TARGET_ARCH
TARGET_ARCH[doc] = "The architecture of the device being built. The OpenEmbedded build system supports the following architectures: arm, mips, ppc, x86, x86-64."

  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` variable.

TARGET_AS_ARCH
TARGET_AS_ARCH[doc] = "Specifies architecture-specific assembler flags for the target system."

  Specifies architecture-specific assembler flags for the target system. `TARGET_AS_ARCH` is initialized from `TUNE_ASARGS` by default in the BitBake configuration file (`meta/conf/bitbake.conf`):

           TARGET_AS_ARCH = "${TUNE_ASARGS}"

TARGET_CC_ARCH
TARGET_CC_ARCH[doc] = "Specifies architecture-specific C compiler flags for the target system."

  Specifies architecture-specific C compiler flags for the target system. `TARGET_CC_ARCH` is initialized from `TUNE_CCARGS` by default.

  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
TARGET_CC_KERNEL_ARCH[doc] = "This is a specific kernel compiler flag for a CPU or Application Binary Interface (ABI) tune."

  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` 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 for an example.

TARGET_CFLAGS
TARGET_CFLAGS[doc] = "Flags passed to the C compiler for the target system. This variable evaluates to the same as CFLAGS."

  Specifies the flags to pass to the C compiler when building for the target. When building in the target context, `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
TARGET_CPPFLAGS[doc] = "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."

  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` 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
TARGET_CXXFLAGS[doc] = "Specifies the flags to pass to the C++ compiler when building for the target."

  Specifies the flags to pass to the C++ compiler when building for the target. When building in the target context, `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
TARGET_FPU[doc] = "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."

  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
TARGET_LD_ARCH[doc] = "Specifies architecture-specific linker flags for the target system."

  Specifies architecture-specific linker flags for the target system. `TARGET_LD_ARCH` is initialized from `TUNE_LDARGS` by default in the BitBake configuration file (`meta/conf/bitbake.conf`):

           TARGET_LD_ARCH = "${TUNE_LDARGS}"

TARGET_LDFLAGS
TARGET_LDFLAGS[doc] = "Specifies the flags to pass to the linker when building for the target."

  Specifies the flags to pass to the linker when building for the target. When building in the target context, `LDFLAGS` is set to the value of this variable by default.

  Additionally, the SDK's environment setup script sets the `LDFLAGS` variable in the environment to the `TARGET_LDFLAGS` value so that executables built using the SDK also have the flags applied.

TARGET_OS
TARGET_OS[doc] = "Specifies the target's operating system."

  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
TARGET_PREFIX[doc] = "The prefix used for the toolchain binary target tools."

  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}-".

  - 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
TARGET_SYS[doc] = "The target system is comprised of TARGET_ARCH,TARGET_VENDOR and TARGET_OS."

  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`, `TARGET_VENDOR`, and `TARGET_OS` variables.

  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
TARGET_VENDOR[doc] = "The name of the target vendor."

  Specifies the name of the target vendor.

TCLIBC
TCLIBC[doc] = "Specifies GNU standard C library (libc) variant to use during the build process. You can select 'glibc', 'musl' or "newlib."

  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
TCLIBCAPPEND[doc] = "Specifies a suffix appended to TMPDIR that identifies the libc variant for the build."

  Specifies a suffix to be appended onto the `TMPDIR` value. The suffix identifies the `libc` variant for building. When you are building for multiple variants with the same 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
TCMODE[doc] = "Enables an external toolchain (where provided by an additional layer) if set to a value other than 'default'."

  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.

  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`, 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 .

  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
TEST_EXPORT_DIR[doc] = "The location the OpenEmbedded build system uses to export tests when the TEST_EXPORT_ONLY variable is set to "1"."

  The location the OpenEmbedded build system uses to export tests when the `TEST_EXPORT_ONLY` variable is set to "1".

  The `TEST_EXPORT_DIR` variable defaults to `"${TMPDIR}/testimage/${PN}"`.

TEST_EXPORT_ONLY
TEST_EXPORT_ONLY[doc] = "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."

  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
TEST_LOG_DIR[doc] = "Holds the SSH log and the boot log for QEMU machines. The TEST_LOG_DIR variable defaults to "${WORKDIR}/testimage"."

  Holds the SSH log and the boot log for QEMU machines. The `TEST_LOG_DIR` variable defaults to `"${WORKDIR}/testimage"`.

  Actual test results reside in the task log (`log.do_testimage`), which is in the `${WORKDIR}/temp/` directory.

TEST_POWERCONTROL_CMD
TEST_POWERCONTROL_CMD[doc] = "For automated hardware testing, specifies the command to use to control the power of the target machine under test"

  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
TEST_POWERCONTROL_EXTRA_ARGS[doc] = "For automated hardware testing, specifies additional arguments to pass through to the command specified in TEST_POWERCONTROL_CMD"

  For automated hardware testing, specifies additional arguments to pass through to the command specified in `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
TEST_QEMUBOOT_TIMEOUT[doc] = "The time in seconds allowed for an image to boot before automated runtime tests begin to run against an image."

  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" section in the Yocto Project Development Tasks Manual.

TEST_SERIALCONTROL_CMD
TEST_SERIALCONTROL_CMD[doc] = "For automated hardware testing, specifies the command to use to connect to the serial console of the target machine under test."

  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
TEST_SERIALCONTROL_EXTRA_ARGS[doc] = "For automated hardware testing, specifies additional arguments to pass through to the command specified in TEST_SERIALCONTROL_CMD."

  For automated hardware testing, specifies additional arguments to pass through to the command specified in `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
TEST_SERVER_IP[doc] = "The IP address of the build machine (host machine). This IP address is usually automatically detected."

  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).

  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
TEST_TARGET[doc] = "For automated runtime testing, specifies the method of deploying the image and running tests on the target machine."

  Specifies the target controller to use when running tests against a test image. The default controller to use is "QemuTarget":

           TEST_TARGET = "QemuTarget"

  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`:

  - "QemuTarget": Boots a QEMU image and runs the tests. See the "Enabling Runtime Tests on QEMU" section in the Yocto Project Development Tasks Manual for more information.

  - "SimpleRemoteTarget": 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` when you use "SimpleRemoteTarget".

    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" section in the Yocto Project Development Tasks Manual.

TEST_TARGET_IP
TEST_TARGET_IP[doc] = "The IP address of your hardware under test."

  The IP address of your hardware under test. The `TEST_TARGET_IP` variable has no effect when `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
TEST_SUITES[doc] = "An ordered list of tests (modules) to run against an image when performing automated runtime testing."

  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.

  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" section in the Yocto Project Development Tasks Manual.

TESTIMAGE_AUTO
TESTIMAGE_AUTO[doc] = "Enables automatic testing of an image once it is built."

  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 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" section in the Yocto Project Development Tasks Manual and the "`testimage*.bbclass`" section.
THISDIR
THISDIR[doc] = "The directory in which the file BitBake is currently parsing is located."

  The directory in which the file BitBake is currently parsing is located. Do not manually set this variable.

TIME
TIME[doc] = "The time the build was started using HMS format."

  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
TMPDIR[doc] = "The temporary directory the OpenEmbedded build system uses when it does its work building images. By default, the TMPDIR variable is named tmp within the Build Directory."

  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.

  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:

           #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
TOOLCHAIN_HOST_TASK[doc] = "This variable lists packages the OpenEmbedded build system uses when building an SDK, which contains a cross-development environment."

  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`, 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" 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" 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) manual.

TOOLCHAIN_OUTPUTNAME
TOOLCHAIN_OUTPUTNAME[doc] = "Defines the name used for the toolchain output."

  This variable defines the name used for the toolchain output. The `populate_sdk_base` class sets the `TOOLCHAIN_OUTPUTNAME` variable as follows:

           TOOLCHAIN_OUTPUTNAME ?= "${SDK_NAME}-toolchain-${SDK_VERSION}"

  See the `SDK_NAME` and `SDK_VERSION` variables for additional information.
TOOLCHAIN_TARGET_TASK
TOOLCHAIN_TARGET_TASK[doc] = "This variable lists packages the OpenEmbedded build system uses when it creates the target part of an SDK, which includes libraries and headers."

  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" 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" 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) manual.

TOPDIR
TOPDIR[doc] = "The Build Directory. BitBake automatically sets this variable. The OpenEmbedded build system uses the Build Directory when building images."

  The top-level Build Directory. BitBake automatically sets this variable when you initialize your build environment using `&OE_INIT_FILE;`.

TRANSLATED_TARGET_ARCH
TRANSLATED_TARGET_ARCH[doc] = "A sanitized version of TARGET_ARCH. This variable is used where the architecture is needed in a value where underscores are not allowed."

  A sanitized version of `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
TUNE_ARCH[doc] = "The GNU canonical architecture for a specific architecture (i.e. arm, armeb, mips, mips64, and so forth)."

  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 provides information for `TUNE_ARCH` specific to the `mips` architecture.

  `TUNE_ARCH` is tied closely to `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
TUNE_ASARGS[doc] = "Specifies architecture-specific assembler flags for the target system."

  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`. 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)}"

  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
TUNE_CCARGS[doc] = "Specifies architecture-specific C compiler flags for the target system."

  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`.

  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
TUNE_LDARGS[doc] = "Specifies architecture-specific linker flags for the target system."

  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`. 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)}"

  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
TUNE_FEATURES[doc] = "Features used to "tune" a compiler for optimal use given a specific processor."

  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` variable for more information.
TUNE_PKGARCH
TUNE_PKGARCH[doc] = "The package architecture understood by the packaging system to define the architecture, ABI, and tuning of output packages."

  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
TUNEABI[doc] = "An underlying ABI used by a particular tuning in a given toolchain layer. This feature allows providers using prebuilt libraries to check compatibility of a tuning against their selection of libraries."

  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`, and `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` class to see how the variable is used.

TUNEABI_OVERRIDE
TUNEABI_OVERRIDE[doc] = "If set, ignores TUNEABI_WHITELIST."

  If set, the OpenEmbedded system ignores the `TUNEABI_WHITELIST` variable. Providers that use prebuilt libraries can use the `TUNEABI_OVERRIDE`, `TUNEABI_WHITELIST`, and `TUNEABI` variables to check compatibility of a tuning against their selection of libraries.

  See the `sanity` class to see how the variable is used.

TUNEABI_WHITELIST
TUNEABI_WHITELIST[doc] = "A whitelist of permissible TUNEABI values. If the variable is not set, all values are allowed."

  A whitelist of permissible `TUNEABI` values. If `TUNEABI_WHITELIST` is not set, all tunes are allowed. Providers that use prebuilt libraries can use the `TUNEABI_WHITELIST`, `TUNEABI_OVERRIDE`, and `TUNEABI` variables to check compatibility of a tuning against their selection of libraries.

  See the `sanity` class to see how the variable is used.

TUNECONFLICTS[feature]
TUNECONFLICTS[doc] = "Specifies CPU or Application Binary Interface (ABI) tuning features that conflict with specified 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. 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]
TUNEVALID[doc] = "Descriptions, stored as flags, of valid tuning features."

  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 for these features.

### U

UBOOT_CONFIG
UBOOT_CONFIG[doc] = "Configures the UBOOT_MACHINE and can also define IMAGE_FSTYPES for individual cases."

  Configures the `UBOOT_MACHINE` and can also define `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` class.

UBOOT_ENTRYPOINT
UBOOT_ENTRYPOINT[doc] = "Specifies the entry point for the U-Boot image."

  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
UBOOT_LOADADDRESS[doc] = "Specifies the load address for the U-Boot image."

  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
UBOOT_LOCALVERSION[doc] = "Appends a string to the name of the local version of the U-Boot image."

  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
UBOOT_MACHINE[doc] = "Specifies the value passed on the make command line when building a U-Boot image."

  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
UBOOT_MAKE_TARGET[doc] = "Specifies the target called in the Makefile."

  Specifies the target called in the `Makefile`. The default target is "all".

UBOOT_SUFFIX
UBOOT_SUFFIX[doc] = "Points to the generated U-Boot extension."

  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
UBOOT_TARGET[doc] = "Specifies the target used for building U-Boot."

  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.

UNKNOWN_CONFIGURE_WHITELIST
UNKNOWN_CONFIGURE_WHITELIST[doc] = "Specifies a list of options that, if reported by the configure script as being invalid, should not generate a warning during the do_configure task."

  Specifies a list of options that, if reported by the configure script as being invalid, should not generate a warning during the `do_configure` task. Normally, invalid configure options are simply not passed to the configure script (e.g. should be removed from `EXTRA_OECONF` or `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` class and is only enabled if the recipe inherits the `autotools` class.

UPDATERCPN
UPDATERCPN[doc] = "Specifies the package that contains the initscript that is enabled."

  For recipes inheriting the `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
UPSTREAM_CHECK_GITTAGREGEX[doc] = "Filters relevant Git tags when fetching source from an upstream Git repository."

  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
UPSTREAM_CHECK_REGEX[doc] = "The regular expression the package checking system uses to parse the page pointed to by UPSTREAM_CHECK_URI."

  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`.

           UPSTREAM_CHECK_REGEX = "package_regex"

UPSTREAM_CHECK_URI
UPSTREAM_CHECK_URI[doc] = "The URL used by the package checking system to get the latest version of the package when source files are fetched from an upstream Git repository."

  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
USE_DEVFS[doc] = "Determines if devtmpfs is used for /dev population."

  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" section in the Yocto Project Development Tasks Manual for information on how to use this variable.

USE_VT
USE_VT[doc] = "When using SysVinit, determines whether or not to run a getty on any virtual terminals in order to enable logging in through those terminals."

  When using SysVinit, determines whether or not to run a getty 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
USER_CLASSES[doc] = "List of additional classes to use when building images that enable extra features."

  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.
USERADD_ERROR_DYNAMIC
USERADD_ERROR_DYNAMIC[doc] = "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 files/passwd and files/group files. If set to 'warn', a warning will be issued instead."

  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 `files/passwd` and `files/group` files. 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`, `USERADD_UID_TABLES`, and `USERADD_GID_TABLES` variables.
USERADD_GID_TABLES
USERADD_GID_TABLES[doc] = "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."

  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` 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"

  Setting the `USERADDEXTENSION` variable to "useradd-staticids" causes the build system to use static `gid` values.

USERADD_PACKAGES
USERADD_PACKAGES[doc] = "When a recipe inherits the useradd class, this variable specifies the individual packages within the recipe that require users and/or groups to be added."

  When inheriting the `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}"

  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
USERADD_PARAM[doc] = "When a recipe inherits the 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."

  When inheriting the `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 .
USERADD_UID_TABLES
USERADD_UID_TABLES[doc] = "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."

  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` 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"

  Setting the `USERADDEXTENSION` variable to "useradd-staticids" causes the build system to use static `uid` values.

USERADDEXTENSION
USERADDEXTENSION[doc] = "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."

  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`.

  To use static user identification (`uid`) and group identification (`gid`) values, set the variable as follows in your `local.conf` file:

           USERADDEXTENSION = "useradd-staticids"

  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` and `USERADD_GID_TABLES` variables. Additionally, you should also set the `USERADD_ERROR_DYNAMIC` variable.

### V

VOLATILE_LOG_DIR
VOLATILE_LOG_DIR[doc] = "Specifies the persistence of the target's /var/log directory, which is used to house postinstall target log files."

  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.

### W

WARN_QA
WARN_QA[doc] = "Specifies the quality assurance checks whose failures are reported as warnings by the OpenEmbedded build system."

  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`" section.

WKS_FILE_DEPENDS
WKS_FILE_DEPENDS[doc] = "Lists a recipe's build-time dependencies specific to Wic."

  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` 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` 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
WKS_FILE[doc] = "Specifies the name of the wic kickstart 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" section in the Yocto Project Development Tasks Manual. For details on the kickstart file format, see the "OpenEmbedded Kickstart (`.wks`) Reference Chapter.

WORKDIR
WORKDIR[doc] = "The pathname of the working directory in which the OpenEmbedded build system builds a recipe. This directory is located within the TMPDIR directory structure and changes as different packages are built."

  The pathname of the work directory in which the OpenEmbedded build system builds a recipe. This directory is located within the `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

### X

XSERVER
XSERVER[doc] = "Specifies the packages that should be installed to provide an X server and drivers for the current machine."

  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`.

  The default value of `XSERVER`, if not specified in the machine configuration, is "xserver-xorg xf86-video-fbdev xf86-input-evdev".