ref-manual: Added clarifying note to the BBCLASSEXTEND variable.

Fixes [YOCTO #9909]

Added a note that talks about how the BBCLASSEXTEND mechanism
adds recipe variants.

(From yocto-docs rev: a05990ecb760519a685a1c5ddcf2ce3e048bfbf2)

Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Scott Rifenbark 2016-07-12 14:10:13 -07:00 committed by Richard Purdie
parent 48336f5139
commit 640181cce8
1 changed files with 21 additions and 0 deletions

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@ -995,6 +995,27 @@
BBCLASSEXTEND =+ "native nativesdk"
BBCLASSEXTEND =+ "multilib:<replaceable>multilib_name</replaceable>"
</literallayout>
<note>
<para>
Internally, the <filename>BBCLASSEXTEND</filename>
mechanism generates recipe variants by rewriting
variable values and applying overrides such as
<filename>_class-native</filename>.
For example, to generate a native version of a recipe
named "foo", a
<link linkend='var-DEPENDS'><filename>DEPENDS</filename></link>
on "foo" is rewritten to a <filename>DEPENDS</filename>
on "foo-native".
</para>
<para>
No reparsing, which adds some limitations, of the
recipe is done for each variant.
For example, it is not possible to "include" a
different file depending on the variant, since
"include's" are processed when the recipe is parsed.
</para>
</note>
</para>
</glossdef>
</glossentry>