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[3/3] ref-manual: variables: Add example for SYSROOT_DIRS variable

Message ID 20231020094102.414940-3-bhstalel@gmail.com
State New
Headers show
Series [1/3] ref-manual: variables: Add RECIPE_SYSROOT and RECIPE_SYSROOT_NATIVE | expand

Commit Message

Talel BELHADJ SALEM Oct. 20, 2023, 9:41 a.m. UTC 
Signed-off-by: Talel BELHAJSALEM <bhstalel@gmail.com>
---
 documentation/ref-manual/variables.rst | 29 ++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

Comments

Michael Opdenacker Oct. 20, 2023, 1:22 p.m. UTC | #1 
Hi Talel

Thanks for not giving up!

For all 3 commits:
Reviewed-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Merged into master-next.

Thanks again

Michael.
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Patch

diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst
index 1fca913e2..3faa39704 100644
--- a/documentation/ref-manual/variables.rst
+++ b/documentation/ref-manual/variables.rst
@@ -8498,6 +8498,35 @@  system and gives an overview of their function and contents.
              ${libdir}/${BPN}/ptest \
              "
 
+      Consider the following example in which you need to manipulate this variable.
+      Assume you have a recipe ``A`` that provides a shared library ``.so.*`` that is
+      installed into a custom folder other than "``${libdir}``"
+      or "``${base_libdir}``", let's say "``/opt/lib``".
+
+      .. note::
+
+         This is not a recommended way to deal with shared libraries, but this
+         is just to show the usefulness of setting :term:`SYSROOT_DIRS`.
+
+      When a recipe ``B`` :term:`DEPENDS` on ``A``, it means what is in
+      :term:`SYSROOT_DIRS` will be copied from :term:`D` of the recipe ``B``
+      into ``B``'s :term:`SYSROOT_DESTDIR` that is "``${WORKDIR}/sysroot-destdir``".
+
+      Now, since ``/opt/lib`` is not in :term:`SYSROOT_DIRS`, it will never be copied to
+      ``A``'s :term:`RECIPE_SYSROOT`, which is "``${WORKDIR}/recipe-sysroot``". So,
+      the linking process will fail.
+
+      To fix this, you need to add ``/opt/lib`` to :term:`SYSROOT_DIRS`::
+
+         SYSROOT_DIRS:append = " /opt/lib"
+
+      .. note::
+         Even after setting ``/opt/lib`` to :term:`SYSROOT_DIRS`, the linking process will still fail
+         because the linker does not know that location, since :term:`TARGET_LDFLAGS`
+         doesn't contain it (if your recipe is for the target). Therefore, so you should add::
+
+            TARGET_LDFLAGS:append = " -L${RECIPE_SYSROOT}/opt/lib"
+
    :term:`SYSROOT_DIRS_NATIVE`
       Extra directories staged into the sysroot by the
       :ref:`ref-tasks-populate_sysroot` task for