====== Variables ======

  * **DEPENDS** Lists a recipe's build-time dependencies. These are dependencies on other recipes whose contents (e.g. headers and shared libraries) are needed by the recipe at build time. 
  * **RDEPENDS** Lists runtime dependencies of a package. These dependencies are other packages that must be installed in order for the package to function correctly. 

  * **PN** - The recipe name
  * **PR** - The recipe revision
  * **PV** - The recipe version

Build related:
  * **S** (by default ''${WORKDIR}/${BPN}-${PV}'') - directory within build directory, where unpacked recipe source code resides.
  * **B** (by default the same as **S**) - directory within build directory, where objects are generated.
  * **D** - directory within build directory, where components are installed (destination directory)

<code>
Variable name	Definition	        Typical value
-------------  --------------------    --------------------
prefix	        /usr                    /usr
base_prefix	(empty)	                (empty)
exec_prefix	${base_prefix}	        (empty)
base_bindir	${base_prefix}/bin	/bin
base_sbindir	${base_prefix}/sbin	/sbin
base_libdir	${base_prefix}/lib	/lib
datadir         ${prefix}/share	        /usr/share
sysconfdir	/etc	                /etc
localstatedir	/var	                /var
infodir         ${datadir}/info	        /usr/share/info
mandir          ${datadir}/man	        /usr/share/man
docdir          ${datadir}/doc	        /usr/share/doc
servicedir	/srv	                /srv
bindir          ${exec_prefix}/bin	/usr/bin
sbindir         ${exec_prefix}/sbin	/usr/sbin
libexecdir	${exec_prefix}/libexec	/usr/libexec
libdir          ${exec_prefix}/lib	/usr/lib
includedir	${exec_prefix}/include	/usr/include
palmtopdir	${libdir}/opie	        /usr/lib/opie
palmqtdir	${palmtopdir}	        /usr/lib/opie
</code>


====== get current layer dir ======

For ''layer.conf'' scope there is [[https://docs.yoctoproject.org/ref-manual/variables.html#term-LAYERDIR|LAYERDIR}]] variable. But this variable is not exported outside.

Trick is to define own new variable in ''layer.conf'' which is available in recipes:

<code>
MY_DISTRO_LAYER_BASE = '${@os.path.normpath("${LAYERDIR}")}'
</code>

and use in recipe or distro.conf:
<code>
OVERLAYFS_ETC_INIT_TEMPLATE = "${MY_DISTRO_LAYER_BASE}/files/myboard-overlayfs-preinit.sh.in"
</code>