This section lists common variables used in the Yocto Project and gives an overview of their function and contents. A B C D E F H I K L M P R S T W AUTHOR The email address used to contact the original author or authors in order to send patches, forward bugs, etc. AUTOREV Specifies to use the current (newest) source revision. This variable is with the SRCREV variable. BAD_RECOMMENDATIONS A list of packages not to install despite being recommended by a recipe. Support for this variable exists only for images that use the ipkg packaging system. BB_NUMBER_THREADS The maximum number of tasks BitBake should run in parallel at any one time. If your host development system supports mulitiple cores a good rule of thumb is to set this variable to twice the number of cores. BBFILE_COLLECTIONS Lists the names of configured layers. These names are used to find the other BBFILE_* variables. Typically, each layer will append its name to this variable in its conf/layer.conf file. BBFILE_PATTERN Variable that expands to match files from BBFILES in a particular layer. This variable is used in the conf/layer.conf file and must be suffixed with the name of the specific layer (e.g. BBFILE_PATTERN_emenlow). BBFILE_PRIORITY Assigns the priority for recipe files in each layer. This variable is useful in situations where the same package appears in more than one layer. Setting this variable allows you to prioritize a layer against other layers that contain the same package - effectively letting you control the precedence for the multiple layers. The precedence established through this variable stands regardless of a layer's package version (PV variable). For example, a layer that has a package 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 List of recipe files used by BitBake to build software BBPATH Used by BitBake to locate .bbclass and configuration files. This variable is analogous to the PATH variable. BBINCLUDELOGS Variable that controls how BitBake displays logs on build failure. BBLAYERS Lists the layers to enable during the Yocto Project build. This variable is defined in the bblayers.conf configuration file in the Yocto Project build directory. Here is an example: BBLAYERS = " \ /home/scottrif/poky/meta \ /home/scottrif/poky/meta-yocto \ /home/scottrif/poky/meta-mykernel \ " This example enables three layers, one of which is a custom, user-defined layer named meta-mykernel. BPN Bare name of package with any suffixes like -cross -native removed. CFLAGS Flags passed to C compiler for the target system. This variable evaluates to the same as TARGET_CFLAGS. COMPATIBLE_MACHINE A regular expression which evaluates to match the machines the recipe works with. It stops recipes being run on machines for which they are not compatible. This is particularly useful with kernels. It also helps to increase parsing speed as further parsing of the recipe is skipped if it is found the current machine is not compatible. CONFIG_SITE A list of files that contains autoconf test results relevant to the current build. This variable is used by the Autotools utilities when running configure. D The destination directory. DEBUG_BUILD Specifies to build packages with debugging information. This influences the value of the SELECTED_OPTIMIZATION variable. DEBUG_OPTIMIZATION The options to pass in TARGET_CFLAGS and CFLAGS when compiling a system for debugging. This variable defaults to "-O -fno-omit-frame-pointer -g". DEFAULT_PREFERENCE Specifies the priority of recipes. DEPENDS A list of build-time dependencies for a given recipe. The variable indicates recipes that must have been staged before a particular recipe can configure. DESCRIPTION The package description used by package managers. DESTDIR the destination directory. DISTRO The short name of the distribution. DISTRO_EXTRA_RDEPENDS The list of packages required by the distribution. DISTRO_EXTRA_RRECOMMENDS The list of packages which extend usability of the image. Those packages will automatically be installed but can be removed by user. DISTRO_FEATURES The features of the distribution. DISTRO_NAME The long name of the distribution. DISTRO_PN_ALIAS Alias names used for the recipe in various Linux distributions. See Handling a Package Name Alias section for more information. DISTRO_VERSION the version of the distribution. DL_DIR The directory where all fetched sources will be stored. ENABLE_BINARY_LOCALE_GENERATION Variable that controls which locales for eglibc are to be generated during the build (useful if the target device has 64Mbytes of RAM or less). EXTRA_IMAGE_FEATURES Allows extra packages to be added to the generated images. You set this variable in the local.conf configuration file. Note that some image features are also added using the IMAGE_FEATURES variable generally configured in image recipes. You can use this variable to add more features in addition to those. 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. "dev-pkgs" - Adds -dev packages for all installed packages. This is useful if you want to develop against the libraries in the image. "tools-sdk" - Adds development tools such as gcc, make, pkgconfig and so forth. "tools-debug" - Adds debugging tools such as gdb and strace. "tools-profile" - Adds profiling tools such as oprofile, exmap, lttng and valgrind (x86 only). "tools-testapps" - Adds useful testing tools such as ts_print, aplay, arecord and so forth. "debug-tweaks" - Makes an image suitable for development. For example, ssh root access has a blank password. You should remove this feature before you produce a production image. There are other application targets too, see meta/classes/poky-image.bbclass and meta/packages/tasks/task-poky.bb for more details. EXTRA_OECMAKE Additional cmake options. EXTRA_OECONF Additional configure script options. EXTRA_OEMAKE Additional GNU make options. FILES The list of directories or files that are placed in packages. FILESYSTEM_PERMS_TABLES Allows you to define your own file permissions settings table as part of your configuration for the packaging process. By default, the Yocto Project uses the fs-perms.txt, which is located in the meta/files directory of the Yocto Project files directory. While it is recommended that you just allow the build system to use the default fs-perms.txt, you can create and use your own file permissions file and then set the FILESYSTEM_PERMS_TABLES variable to point to that file. If you create your own file permissions setting table, you should place it in your layer or the distros layer. You define the FILESYSTEM_PERMS_TABLES variable in the conf/local.conf file found in the Yocto Project's build directory. For guidance on how to create your own file permissions settings table file, see the fs-perms.txt. FULL_OPTIMIZATION The options to pass in TARGET_CFLAGS and CFLAGS when compiling an optimised system. This variable defaults to "-fexpensive-optimizations -fomit-frame-pointer -frename-registers -O2". HOMEPAGE Website where more info about package can be found IMAGE_FEATURES The list of features present in images. Typically, you configure this variable in image recipes. Note that you can add extra features to the image by using the EXTRA_IMAGE_FEATURES variable. See the Reference: Images section for the list of features present in images built by the Yocto Project. IMAGE_FSTYPES Formats of root filesystem images that you want to have created. IMAGE_INSTALL The list of packages used to build images. INC_PR Defines the Package revision. You manually combine values for INC_PR into the PR field of the parent recipe. When you change this variable, you change the PR value for every person that includes the file. The following example shows how to use the INC_PR variable given a common .inc file that defines the variable. Once defined, you can use the variable to set the PR value: recipes-graphics/xorg-font/font-util_1.1.1.bb:PR - "$(INC_PR).1" recipes-graphics/xorg-font/xorg-font-common.inc:INC_PR - "r1" recipes-graphics/xorg-font/encondings_1.0.3.bb:PR - "$(INC_PR).1" recipes-graphics/xorg-font/fiont-alias_1.0.2.bb:PR - "$(INC_PR).0" INHIBIT_PACKAGE_STRIP Causes the build to not strip binaries in resulting packages. INHERIT Causes the named class to be inherited at this point during parsing. The variable is only valid in configuration files. INITSCRIPT_PACKAGES A list of the packages that contain initscripts. If multiple packages are specified, you need to append the package name to the other INITSCRIPT_* as an override. This variable is used in recipes when using update-rc.d.bbclass. The variable is optional and defaults to the PN variable. INITSCRIPT_NAME The filename of the initscript (as installed to ${etcdir}/init.d). This variable is used in recipes when using update-rc.d.bbclass. The variable is Mandatory. INITSCRIPT_PARAMS Specifies the options to pass to update-rc.d. An example is start 99 5 2 . stop 20 0 1 6 ., which gives the script a runlevel of 99, starts the script in initlevels 2 and 5, and stops the script in levels 0, 1 and 6. The variable is mandatory and is used in recipes when using update-rc.d.bbclass. KERNEL_IMAGETYPE The type of kernel to build for a device, usually set by the machine configuration files and defaults to "zImage". This variable is used when building the kernel and is passed to make as the target to build. LAYERDEPENDS Lists the layers that this recipe depends upon, separated by spaces. Optionally, you can specify a specific layer version for a dependency by adding it to the end of the layer name with a colon, (e.g. "anotherlayer:3" to be compared against LAYERVERSION_anotherlayer in this case). An error will be produced if any dependency is missing or the version numbers do not match exactly (if specified). This variable is used in the conf/layer.conf file and must be suffixed with the name of the specific layer (e.g. LAYERDEPENDS_mylayer). LAYERDIR When used inside the layer.conf configuration file, this variable provides the path of the current layer. This variable requires immediate expansion (see the BitBake manual) as lazy expansion can result in the expansion happening in the wrong directory and therefore giving the wrong value. LAYERVERSION 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). LICENSE The list of package source licenses. LIC_FILES_CHKSUM Checksums of the license text in the recipe source code. This variable tracks changes in license text of the source code files. If the license text is changed, it will trigger a build failure, which gives the developer an opportunity to review any license change. This variable must be defined for all recipes (unless LICENSE is set to "CLOSED") For more information, see the Track License Change section MACHINE Specifies the target device. MACHINE_ESSENTIAL_RDEPENDS Specifies the list of packages required to boot the device. MACHINE_ESSENTIAL_RRECOMMENDS Specifies the list of packages required to boot the device (usually additional kernel modules). MACHINE_EXTRA_RDEPENDS Specifies the list of packages required to use the devices MACHINE_EXTRA_RRECOMMENDS Specifies the list of packages useful to use the device (e.g. additional kernel modules) MACHINE_FEATURES Specifies the list of device features. See the Machine section for more information. MAINTAINER The email address of the distribution maintainer. PACKAGE_ARCH The architecture of the resulting package. PACKAGE_CLASSES This variable, which is set in the local.conf configuration file found in the Yocto Project file's conf directory, specifies the package manager to use when packaging data. You can provide one or more arguments for the variable with the first argument being the package manager used to create images: PACKAGE_CLASSES ?= "package_rpm package_deb package_ipk" For information on build performance effects as a result of the package manager use, see Packaging - package*.bbclass in this manual. PACKAGE_DESCRIPTION The long form description of the binary package for packaging systems such as ipkg, rpm or debian. By default, this variable inherits DESCRIPTION. PACKAGE_EXTRA_ARCHS Specifies the list of architectures compatible with the device CPU. This variable is useful when you build for several different devices that use miscellaneous processors such as XScale and ARM926-EJS). PACKAGE_SUMMARY The short (72 character limit suggested) summary of the binary package for packaging systems such as ipkg, rpm or debian. By default, this variable inherits DESCRIPTION. PACKAGES The list of packages to be created from the recipe. The default value is "${PN}-dbg ${PN} ${PN}-doc ${PN}-dev". PARALLEL_MAKE Specifies extra options that are passed to the make command during the compile tasks. This variable is usually in the form -j 4, where the number represents the maximum number of parallel threads make can run. If you development host supports multiple cores a good rule of thumb is to set this variable to one and a half times the number of cores on the host. PN The name of the package. PR The revision of the package. The default value for this variable is "r0". PV The version of the package. The version is normally extracted from the recipe name. For example, if the recipe is named expat_2.0.1.bb, then PV will be 2.0.1. PV is generally not overridden within a recipe unless it is building an unstable version from a source code repository (e.g. Git or Subversion). PE the epoch of the package. The default value is "0". The field is used to make upgrades possible when the versioning scheme changes in some backwards incompatible way. PREFERRED_PROVIDER If multiple recipes provide an item, this variable determines which recipe should be given preference. The variable should be set to the $PN of the recipe to which you want to give precedence. PREFERRED_VERSION If there are multiple versions of recipes available, this variable determines which recipe should be given preference. The variable should be set to the $PV of the recipe to whichy you want to give precedence. POKY_EXTRA_INSTALL Specifies the list of packages to be added to the image. This variable should only be set in the local.conf configuration file found in the Yocto Project's build directory. POKYLIBC The libc implementation selector. You can select eglibc or uclibc. This release of the Yocto Project does not support the glibc implementation of libc. POKYMODE The toolchain selector. This variable has been replaced by TCMODE. The POKYMODE would select the external toolchain built from the Yocto Project or a few supported combinations of upstream GCC or CodeSourcery Labs toolchain. RCONFLICTS The list of packages that conflict with this package. Note that the package will not be installed if the conflicting packages are not first removed. RDEPENDS A list of run-time dependencies for a package. These packages need to be installed alongside the package to which they apply. This enables the package to run correctly. For example, consider a Perl script, which depends on the Perl package. Since this variable applies to output packages, there should always be an override attached to this variable specifying the runtime package to which to add the dependency (e.g. RDEPENDS_${PN}-dev). Names in this field must appear as they appear in the PACKAGES namespace before any renaming of the output package by classes like debian.bbclass. Some automatic handling occurs around the RDEPENDS variable: shlibdeps: If a runtime package contains a shared library (.so), the build processes the library in order to determine other libraries to which it is dynamically linked. The build process adds these libraries to RDEPENDS to create the runtime package. pcdeps: If the package ships a pkg-config information file, the build process uses this file to add items to the RDEPENDS variable to create the runtime packages. ROOT_FLASH_SIZE The size of root filesystem as measured in megabytes. RRECOMMENDS The list of packages that extend usability of the package. The packages are automatically installed but can be removed by user. RREPLACES The list of packages that are replaced with this package. S The path to unpacked sources. By default, this path is "${WORKDIR}/${PN}-${PV}". SECTION The section where package should be put. Package managers use this variable. SELECTED_OPTIMIZATION The variable takes the value of FULL_OPTIMIZATION unless DEBUG_BUILD = "1". In this case the value of DEBUG_OPTIMIZATION is used. SERIAL_CONSOLE The speed and device for the serial port used to attach the serial console. This variable is given to the kernel as the "console" parameter and after booting occurs getty is started on that port so remote login is possible. SSTATE_DIR The directory for the shared state. SHELLCMDS A list of commands to run within the shell. The list is used by TERMCMDRUN. SITEINFO_ENDIANNESS Specifies the endian byte order of the target system. The variable is either "le" for little-endian or "be" for big-endian. SITEINFO_BITS Specifies the number of bits for the target system CPU. The variable is either "32" or "64". SRC_URI The list of source files - local or remote. SRC_URI_OVERRIDES_PACKAGE_ARCH By default, the Yocto Project automatically detects whether SRC_URI contains files that are machine-specific. If so, the Yocto Project automatically changes PACKAGE_ARCH. Setting this variable to "0" disables this behaviour. SRCDATE The date of the source code used to build the package. This variable applies only if the source was fetched from a Source Code Manager (SCM). SRCREV The revision of the source code used to build the package. This variable applies to Subversion, Git, Mercurial and Bazaar only. Note that if you wish to build a fixed revision and you wish 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. STAGING_KERNEL_DIR The directory with kernel headers that are required to build out-of-tree modules. STAMPS The directory (usually TMPDIR/stamps) with timestamps of executed tasks. SUMMARY The short (72 characters or less) summary of the binary package for packaging systems such as ipkg, rpm or debian. By default, this variable inherits DESCRIPTION. TARGET_ARCH The architecture of the device being built. While a number of values are possible, the Yocto Project primarily supports arm and i586. TARGET_CFLAGS Flags passed to the C compiler for the target system. This variable evaluates to the same as CFLAGS. TARGET_FPU Specifies the method for handling FPU code. For FPU-less targets, which include most ARM CPUs, the variable must be set to "soft". If not, the kernel emulation gets used, which results in a performance penalty. TARGET_OS Specifies the target's operating system. The variable can be set to "linux" for eglibc-based systems and to "linux-uclibc" for uclibc. For ARM/EABI targets, there are also "linux-gnueabi" and "linux-uclibc-gnueabi" values possible. TCMODE The toolchain selector. This variable replaces POKYMODE. The variable determines which of the files in meta/conf/distro/include/tcmode-* is used. By default, TCMODE is set to "default", which chooses tcmode-default.inc. The variable is similar to TCLIBC, which controls the libc used: eglibc or uclibc. TERMCMD This command is used by BitBake to launch a terminal window with a shell. The shell is unspecified so the user's default shell is used. By default, the variable is set to "xterm" but it can be any X11 terminal application or a terminal multiplexer such as screen. While KONSOLE_TERMCMD and KONSOLE_TERMCMDRUN are provided and will work with KDE's Konsole terminal application Konsole from KDE 3, Konsole in KDE 4.0 and later versions will no longer work here due to the fact that it now launches in the background by default, and it is not practically possible to wait until it has terminated. It is hoped that this can be fixed in a future version. TERMCMDRUN This variable is similar to TERMCMD. However, instead of running the user's shell, the command specified by the SHELLCMDS variable is run. WORKDIR The path to directory in tmp/work/ where the package is built.