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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/bitbake-user-manual/bitbake-user-manual-metadata.rst | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/doc/bitbake-user-manual/bitbake-user-manual-metadata.rst b/doc/bitbake-user-manual/bitbake-user-manual-metadata.rst index b839e669c..deb7afad4 100644 --- a/doc/bitbake-user-manual/bitbake-user-manual-metadata.rst +++ b/doc/bitbake-user-manual/bitbake-user-manual-metadata.rst @@ -319,6 +319,10 @@ The variable ``D`` becomes "dvaladditional data". You must control all spacing when you use the override syntax. +.. note:: + + The overrides are applied in this order, ":append", ":prepend", ":remove". + It is also possible to append and prepend to shell functions and BitBake-style Python functions. See the ":ref:`bitbake-user-manual/bitbake-user-manual-metadata:shell functions`" and ":ref:`bitbake-user-manual/bitbake-user-manual-metadata:bitbake-style python functions`" sections for examples. @@ -352,6 +356,28 @@ The variable ``FOO`` becomes Like ":append" and ":prepend", ":remove" is applied at variable expansion time. +.. note:: + + The overrides are applied in this order, ":append", ":prepend", ":remove". + This implies it is not possible to re-append previously removed strings. + However, one can undo a ":remove" by using an intermediate variable whose + content is passed to the ":remove" so that modifying the intermediate + variable equals to keeping the string in:: + + FOOREMOVE = "123 456 789" + FOO:remove = "${FOOREMOVE}" + ... + FOOREMOVE = "123 789" + + This expands to ``FOO:remove = "123 789"``. + +.. note:: + + Override application order may not match variable parse history, i.e. + the output of ``bitbake -e`` may contain ":remove" before ":append", + but the result will be removed string, because ":remove" is handled + last. + Override Style Operation Advantages ----------------------------------- |