The externalsrc
class supports building software
from source code that is external to the OpenEmbedded build system.
Building software from an external source tree means that the build
system's normal fetch, unpack, and patch process is not used.
By default, the OpenEmbedded build system uses the
S
and
B
variables to
locate unpacked recipe source code and to build it, respectively.
When your recipe inherits the externalsrc
class,
you use the
EXTERNALSRC
and
EXTERNALSRC_BUILD
variables to ultimately define S
and
B
.
By default, this class expects the source code to support recipe builds
that use the B
variable to point to the directory in which the OpenEmbedded build
system places the generated objects built from the recipes.
By default, the B
directory is set to the
following, which is separate from the source directory
(S
):
${WORKDIR}/${BPN}/{PV}/
See these variables for more information:
WORKDIR
,
BPN
, and
PV
,
For more information on the
externalsrc
class, see the comments in
meta/classes/externalsrc.bbclass
in the
Source Directory.
For information on how to use the externalsrc
class, see the
"Building Software from an External Source"
section in the Yocto Project Development Manual.