5.1. Variables Reference

The following variables are provided by PTXdist to simplify creating rule files. Every developer should use these variables in every single line in the rule file to avoid any further adaption when external paths are changed.

To get their content related to the current project, we can simply run a:

$ ptxdist print PTXDIST_TOPDIR

Replace the PTXDIST_TOPDIR with one of the other generic variables PTXdist provides.

Global Variables


Points always to the installation directory of PTXdist.


Everything that references PTXDIST_WORKSPACE will use the active projects’s folder.


PTXDIST_SYSROOT_CROSS points to a directory tree all cross relevant executables, libraries and header files are installed to in the current project. All of the project’s packages built for the host to create data for the target are searching in this directory tree for their dependencies (executables, header and library files). Use $(PTXDIST_SYSROOT_CROSS)/usr/bin to install executables, $(PTXDIST_SYSROOT_CROSS)/usr/include for header files and $(PTXDIST_SYSROOT_CROSS)/usr/lib for libraries.


PTXDIST_SYSROOT_HOST points to a directory tree all host relevant executables, libraries and header files are installed to. All project’s packages built for the host are searching in this directory tree for their dependencies (executables, header and library files). Use $(PTXDIST_SYSROOT_HOST)/usr/bin to install executables, $(PTXDIST_SYSROOT_HOST)/usr/include for header files and $(PTXDIST_SYSROOT_HOST)/usr/lib for libraries.


PTXDIST_SYSROOT_TARGET points to a directory tree all target relevant libraries and header files are installed to. All project’s packages built for the target are searching in this directory tree for their dependencies (header and library files). These files are for compile time only (for example to link a target executable against a target library), not for run-time! Use $(PTXDIST_SYSROOT_TARGET)/include for header files and $(PTXDIST_SYSROOT_TARGET)/lib for libraries.

Other useful variables:


Use to find cross tools. This path must be used to create anything that depends on the target’s architecture, but needs something running on the host to do the job. Examples:

Creating a UBI image from the target’s root filesystem

This will need a tool running on the host, but it will create data or code that runs on or is used on the target

Building a library for the target

If this library needs other resources to be built (other libraries) its configure finds the right information in this path.


Used to find host tools. This path must be used to create anything that doesn’t depend on the architecture.


ROOTDIR points to the root of the target’s root filesystem in the current project. Used in very rare cases (to create strange packages based on data in target’s root filesystem for example).


PTXCONF_PLATFORM expands to the name of the currently selected platform. This name is used in various file names and paths.


PTXDIST_PLATFORMSUFFIX expands to the name of the currently selected platform, but with a leading dot. This is used in various files PTXdist should search for.


PTXDIST_PLATFORMCONFIGDIR points to the directory tree of the currently selected platform. This path is used in various search functions.


PTXDIST_PLATFORMDIR points to the directory build tree of the currently selected platform.


PACKAGES is a list of space-separated lowercase package names that are built and installed during the PTXdist build run, and installed into the target root filesystem when building images.

The -y variant contains only those packages that are selected with PTXCONF_<PKG>=y, while the -m variant contains only those which are selected with PTXCONF_<PKG>=m (used for collections). A target package rule usually adds its name to one of those variables if it has been selected. The union of those two sets then ends up in PACKAGES.


In analogy to PACKAGES, target packages that are added to these lists will be built normally during the build run. In contrast however, they are not installed into a root filesystem by default when building images, and image rules must request them explicitly. This is useful for specialized packages that are only needed for specific images, see Creating Individual Root-Filesystems for each Variant.


Similar to PACKAGES, these variables contain the host and cross packages that are built and installed during the PTXdist build run. There are analogous -y and -m variants of those variables too.

Package Specific Variables

For the following variables <PKG> is a placeholder for the package name. It is also the Kconfig symbol name (without the PTXCONF_ prefix).

Package Definition


This is the name of the package including version. For most packages, this is the name of the source archive (without suffix) and the source directory. PTXdist will search for patches in a directory with this name. This is usually defined as <name>-$(<PKG>_VERSION). This variable is required for most packages. The only exception are packages that only install some files in the targetinstall stage (e.g. from projectroot/).


The version of the package. It is used as the version for the ipk packages. As such, it is required for all packages that create such packages. Most target packages fall in this category.


The md5 checksum of the source archive. PTXdist calculates the checksum before extracting the archive and will abort if does not match. Upstream project occasionally change the content of an archive without releasing a new version. This check helps to ensure that all developers work with the same source code.


The archive suffix without the leading ‘.’, e.g. ‘tar.gz’ or ‘zip’. This is only used locally to define <PKG>_URL and <PKG>_SOURCE.


This is the download URL for the source archive. It is a space separated list of URLs. PTXdist will try each URL until it finds one that works. There are two main reasons to provide more than one URL: 1. Additional mirror(s) in case the main location is unavailable. 2. Some projects move old versions into a separate directory when a new version is released. Providing both versions of the URL ensures that PTXdist still has a working URL after the next upstream release.

URLs can have options. Options are appended to the URL separated by ‘;’. For normal downloads the following options are supported:

no-check-certificate to indicate that SSL certificate checking should be disabled.

no-proxy to disable any configured proxy.

cookie:<value> to specify a cookie that should be sent.

Files in the local filesystem can be addressed with file:// URLs. In this case, the URL can also point to a directory. In this case <PKG>_DIR will be a symlink to the specified directory. ‘lndir://’ can be used to create a shadow copy instead. For locations inside the BSP the URL should use $(PTXDIST_WORKSPACE) to define the correct absolute path.

If no source archive is available, PTXdist can get the source from revision control systems. ‘git’ and ‘svn’ are currently supported. Note that this cannot be used to follow a branch! PTXdist will create the archive defined <PKG>_SOURCE and use it if available.

Git URLs must either start with ‘git://’ or end with ‘.git’. They have a mandatory tag=<tagname> option.

SVN URLs must start with ‘svn://’. They have a mandatory rev=r<number> option.

SVN custom tunnel schemes (e.g. ‘svn+ssh’) are supported as well. There is a special treatment for ‘svn+https’. In this case the URL is fixed and ‘svn+’ is removed from URL. This is useful to work around firewalls that block ‘svn’ ports.


The location of the downloaded source archive. There should be no reason to set this to anything other than $(SRCDIR)/$(<PKG>).$(<PKG>_SUFFIX).

For local URLs (file:// or lndir://) <PKG>_SOURCE must not be set.


The name of the patch directory, relative to any of the paths listed in PTXDIST_PATH_PATCHES (i.e., according to the search order described in Patching Packages). If not specified, the default patch directory name is set to the value of the <PKG> variable.

This variable can be set for multiple packages that should share the same patch stack (e.g. kernel packages).


This is the directory where the source archive is extracted. In most cases this is set to $(BUILDDIR)/$(<PKG>). However, if two packages use the same source archive, then something else must be used to make sure that they use different directories. See the rules for ‘gdb’ and ‘gdbserver’ for an example.


The license of the package in the form of an SPDX license expression. The following values have special meaning for PTXdist:

  • custom and custom-exception: for licenses or license exceptions that are considered free software, but do not match any license or license exception known to SPDX.

  • proprietary: for proprietary (non-free) packages

  • ignore for packages without their own license, e.g. meta packages or packages that only install files from projectroot/

  • unknown: no licensing information was extracted yet

See the section Tracking licensing information in packages for more information.


A space separated list of URLs of license text files. The URLs must be file:// URLs relative to <PKG>_DIR. Absolute URLs using $(PTXDIST_WORKSPACE) can be used in case the license text is missing in the upstream archive. Arguments are appended with ‘;’ as separator. The md5=<md5sum> argument is mandatory. It defines the md5 checksum of the full license text. startline=<number>;endline=<number> can be used in case the specified file contains more than just the license text, e.g. if the license is in the header of a source file. For non ASCII or UTF-8 files the encoding can be specified with encoding=<enc>. See the section Tracking licensing information in packages for more information.

For most packages the variables described above are undefined by default. However, for cross and host packages these variables default to the value of the corresponding target package if it exists.


This variable specifies a configuration file of some kind for the packages. For packages with <PKG>_CONF_TOOL set to kconfig the variable must specify an absolute path to the kconfig file. For image packages that use genimage, PTXdist will look for config/images/$(<PKG>_CONFIG) in the BSP and PTXdist in the usual search order.


When PTXdist extracts source archives, it will create <PKG>_DIR first and then extracts the archive there. If <PKG>_STRIP_LEVEL is set to 1 (the default) then PTXdist removes the first directory level defined inside the archive. For most packages that this is the same as just extracting the archive. However, this is useful for packages with badly named top-level directories or packages where the directory must be renamed to avoid collisions (e.g. gdbserver).

The main use-case for <PKG>_STRIP_LEVEL is to set it to 0 for packages without a top-level directory.

In theory <PKG>_STRIP_LEVEL could be set to 2 or more to remove more than one directory level.


If this is set to YES then PTXdist will build the package out of tree. This is only supported for autoconf, qmake and cmake packages. The default is YES for cmake packages and NO for everything else. It will use $(<PKG>_DIR)-build as build directory.

This is especially useful for file:// URLS that point to directories to keep the source tree free of build files.

KEEP can be used instead of YES. In this case the build tree is not deleted at the beginning of the prepare stage. This make reconfiguration faster. This should only be used for packages that can handle configuration changes correctly and rebuild everything as needed.


This is a directory relative to <PKG>_DIR. If set, all build operations are executed in this directory instead. By default <PKG>_SUBDIR is undefined so all operations are executed in the top-level directory.

Build Environment for all Stages


This variable defines the PATH used by all build stages. It is evaluated as is, so it must start with PATH=. If undefined, PTXdist will use PATH=$(CROSS_PATH) for target packages PATH=$(HOST_PATH) for host packages and PATH=$(HOST_CROSS_PATH) for cross packages. It must be set by packages that use the variable locally in the make file or if more directories are added, e.g. to PATH=$(PTXDIST_SYSROOT_CROSS)/usr/bin/qt5:$(CROSS_PATH) for packages that use qmake from Qt5.


Compiler, preprocessor and linker are never called directly in PTXdist. Instead, wrapper scripts are called that expand the command line before calling the actual tool. These variables can be used to influence these wrappers. The specified flags are added to the command line when appropriate. In most cases this it the preferred way to add additional flags. Adding them via environment variables or make arguments can have unexpected side effects, such as as overwriting existing defaults.


A list of arbitrary flags. If any one of these flags is found as an argument to the compiler, preprocessor or linker then the call will fail. This is useful to prevent implicit dependencies: Many packages try to link to libraries at configure time and use them if it works. Adding ‘-l<lib>’ to the blacklist makes it possible to prevent such a detection and explicitly avoid the dependency.


PTXdist has several options in the platformconfig that inject options in the compiler command line. This is used, for example, to add hardening options or change the debug options. This can occasionally cause problems for packages that use the compiler in certain ways, such as the Linux kernel or various bootloaders. With this variable a package can disable individual options by setting it to a space separated list of the corresponding Kconfig symbols (without the PTXCONF_ prefix).


By default, the toolchain wrapper scripts will drop any -I and -L paths that point to directories outside the BSP for target packages. This avoids problems with bad search paths due to broken package build systems.

Sometimes search paths outside the BSP are needed. In this case <PKG>_WRAPPER_ACCEPT_PATHS can be used. It accepts a space separated list of directories. Those directories (with and without symlinks resolved) will not be dropped when the wrapper filters the search paths.

For example, external kernel modules need the kernel source tree. If the kernel is built using an external source tree then search paths to that source tree are needed. So external kernel modules should set <PKG>_WRAPPER_ACCEPT_PATHS to $(KERNEL_DIR).

Prepare Stage


This variable contains the config hash for the package. If it changes, PTXdist rebuilds the prepare stage of the package (and successively, all following stages).

You should not need to touch this variable directly. To add content to the config hash, you can use the macros ptx/cfghash and ptx/cfghash-file.


The environment for the prepare stage. If undefined, PTXdist will use $(CROSS_ENV) for target packages, $(HOST_ENV) for host packages and $(HOST_CROSS_ENV) for cross packages. It must be set by packages that use the variable locally in the make file or if extra variables are added. In this case the definition should start with the default value.


This variable defines what tool is used to configure the package in the prepare stage. Possible values are:

  • NO to do nothing in the prepare stage.

  • autoconf for packages that use autoconf

  • qmake for qmake based packages. Note: the required Qt version must be selected.

  • cmake for cmake based packages. Note HOST_CMAKE must be selected to ensure, that cmake is available for configuration.

  • kconfig for kconfig based packages. Note <PKG>_CONFIG must be set as described above.

  • perl for perl modules.

  • python or python3 for Python packages with a normal setup.py.


This variable adds arguments to the command-line of the configuration tool. If undefined, PTXdist will use a default value that depends on the configuration tool of the package. This default value should also be used when adding additional options. The following defaults exist:

  • autoconf: $(CROSS_AUTOCONF_USR)/$(HOST_AUTOCONF)/$(HOST_CROSS_AUTOCONF) for target/host/cross packages.

  • cmake: $(CROSS_CMAKE_USR)/$(HOST_CMAKE_OPT) for target/host packages. Cross packages cannot be built with cmake

  • qmake: $(CROSS_QMAKE_OPT) for host packages. Host and cross packages cannot be built with qmake.

All other configuration tools have no default options. This variable is ignored for kconfig and python/python3.

Compile Stage


This variables defines additional environment variables for the compile stage. In most cases this variable remains undefined because all necessary defines are picked up in the prepare stage. For python/python3 packages PTXdist will use the default value from <PKG>_CONF_ENV. For packages without configuration tool this must be set correctly, usually based on the <PKG>_CONF_ENV default values, e,g. $(CROSS_ENV) for target packages.


This variables defines additional parameters to be forwarded to make in order to build the package. It defaults to nothing to let make traditionally build the first defined target.


This variables informs PTXdist, if this package can be built in parallel. Some (mostly very smart selfmade) buildsystems fail doing so. In this case this variable can be set to NO. PTXdist will then build this package with one CPU only. The default is, to build packages in parallel.

Install Stage


This variable defaults to install which is used as a target for make. It can be overwritten if the package needs a special target to install its results.


This variable must not be set by the user. It defines package install directory. All files will be installed relative to this directory. It can be used by manual install stages. It is defined as $(PKGDIR)/$(<PKG>) which expands to <platform-dir>/packages/foo-1.1.0 on our foo example.

Targetinstall Stage

The targetinstall stage has no additional variables.

Image Packages

Image packages use a different set of variables. They have the same <PKG> and <PKG>_DIR variables as other packages, but the rest is different.


This is the filename of the image that is created by the rule. This is usually $(IMAGEDIR)/<image-file-name>.


This is a list of tar balls that are extracted to generate the content of the image. PTXdist will add the necessary dependencies to these files to recreate the image as needed. If a tar ball is created by another PTXdist package then this package should be selected in the menu file.


This is another mechanism to add files to the image. It can be used instead of or in addition to <PKG>_FILES. It must be set to a list of ptxdist packages (the lowercase name of the packages). PTXdist will add the necessary dependencies.

Note that this will not ensure that the packages are enabled or that all all package dependencies are satisfied. $(PTX_PACKAGES_INSTALL) can be used to specify all enabled packages. Or $(call ptx/collection, $(PTXDIST_WORKSPACE)/configs/<collection-file-name>) can be used to specify the packages enabled by this collection. In both cases = must be used instead of := due to the makefile include order.


genimage packages use this to specify the genimage configuration file. PTXdist will search for the specified file name in config/images/ in the BSP, platform and PTXdist in the usual search order.


If this is set to YES then PTXdist will create a special nfsroot directory that contains only the files from the packages specified in <PKG>_PKGS. This is useful if the normal nfsroot directory contains conflicting files from multiple images. The created nfsroot directory is <platform-dir>/nfsroot/<image-name>.


This is a tar label to put on an image. This is supported by image-root-tgz and images created with the image-tgz template.