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author | Scott Rifenbark <srifenbark@gmail.com> | 2016-09-01 10:57:39 -0700 |
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committer | Richard Purdie <richard.purdie@linuxfoundation.org> | 2016-09-23 15:27:32 +0100 |
commit | e0347ec2dc98e077a7b2b136e2e54d3bf3b1adda (patch) | |
tree | 77e60a41dd3184ee3b5583c3e1e619f95e475cef /documentation/ref-manual | |
parent | f1879193b90b27f3c9b1e1dccc9097d5913d95b6 (diff) | |
download | openembedded-core-contrib-e0347ec2dc98e077a7b2b136e2e54d3bf3b1adda.tar.gz |
ref-manual: Clarified the OVERRIDES glossary description.
Fixes [YOCTO #10173]
I provided a more detailed description of how this variable
works. Also provided a cross-reference link back to the
variable at the end of the PREFERRED_VERSION variable.
(From yocto-docs rev: 679b205eea541b89e220656f7aa304d0f343c8a6)
Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Diffstat (limited to 'documentation/ref-manual')
-rw-r--r-- | documentation/ref-manual/ref-variables.xml | 63 |
1 files changed, 56 insertions, 7 deletions
diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml index 1f4b2171a9..df1631df83 100644 --- a/documentation/ref-manual/ref-variables.xml +++ b/documentation/ref-manual/ref-variables.xml @@ -8420,18 +8420,60 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" <glossentry id='var-OVERRIDES'><glossterm>OVERRIDES</glossterm> <info> - OVERRIDES[doc] = "BitBake uses OVERRIDES to control what variables are overridden after BitBake parses recipes and configuration files." + OVERRIDES[doc] = "A colon-separated list of overrides that currently apply." </info> <glossdef> <para role="glossdeffirst"> <!-- <para role="glossdeffirst"><imagedata fileref="figures/define-generic.png" /> --> - BitBake uses <filename>OVERRIDES</filename> to control - what variables are overridden after BitBake parses - recipes and configuration files. - You can find more information on how overrides are handled - in the + A colon-separated list of overrides that currently apply. + Overrides are a BitBake mechanism that allows variables to + be selectively overridden at the end of parsing. + The set of overrides in <filename>OVERRIDES</filename> + represents the "state" during building, which includes + the current recipe being built, the machine for which + is being built, and so forth. + </para> + + <para> + As an example, if the string "an-override" appears as an + element in the colon-separated list in + <filename>OVERRIDES</filename>, then the following + assignment will override <filename>FOO</filename> with the + value "overridden" at the end of parsing: + <literallayout class='monospaced'> + FOO_an-override = "overridden" + </literallayout> + See the "<ulink url='&YOCTO_DOCS_BB_URL;#conditional-syntax-overrides'>Conditional Syntax (Overrides)</ulink>" - section of the BitBake User Manual. + section in the BitBake User Manual for more information on + the overrides mechanism. + </para> + + <para> + The default value of <filename>OVERRIDES</filename> + includes the values of the + <link linkend='var-CLASSOVERRIDE'><filename>CLASSOVERRIDE</filename></link>, + <link linkend='var-MACHINEOVERRIDES'><filename>MACHINEOVERRIDES</filename></link>, + and + <link linkend='var-DISTROOVERRIDES'><filename>DISTROOVERRIDES</filename></link> + variables. + Another important override included by default is + <filename>pn-${PN}</filename>. + This override allows variables to be set for a single + recipe within configuration (<filename>.conf</filename>) + files. + Here is an example: + <literallayout class='monospaced'> + FOO_pn-myrecipe = "myrecipe-specific value" + </literallayout> + <note><title>Tip</title> + An easy way to see what overrides apply is to search for + <filename>OVERRIDES</filename> in the output of the + <filename>bitbake -e</filename> command. + See the + "<link linkend='usingpoky-debugging-viewing-variable-values'>Viewing Variable Values</link>" + section for more information. + </note> </para> </glossdef> </glossentry> @@ -9830,6 +9872,13 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" <literallayout class='monospaced'> PREFERRED_VERSION_linux-yocto_forcevariable = "3.4%" </literallayout> + <note> + The <filename>_forcevariable</filename> override is + not handled specially. + This override only works because the default value of + <link linkend='var-OVERRIDES'><filename>OVERRIDES</filename></link> + includes "forcevariable". + </note> </para> </glossdef> </glossentry> |