ref-manual: Added order information for conf file parsing.

I included a new paragraph at the end of the section describing
configuration in the "Closer Look" chapter.  Cases exist when
two configuration files set the same variable.  Depending on the
order, the last configuration file parsed is the one that actually
sets the variable.

Fixes [YOCTO #8914]

(From yocto-docs rev: 260e7dea7879846bcd3f3475cef001e512c657f0)

Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 18 insertions, 3 deletions

diff --git a/documentation/ref-manual/closer-look.xml b/documentation/ref-manual/closer-look.xml
index b0bfae5ba5..8d4aafd464 100644
--- a/documentation/ref-manual/closer-look.xml
+++ b/documentation/ref-manual/closer-look.xml
@@ -255,9 +255,24 @@
 
         <para>
             When you launch your build with the
-            <filename>bitbake <replaceable>target</replaceable></filename> command, BitBake
-            sorts out the configurations to ultimately define your build
-            environment.
+            <filename>bitbake <replaceable>target</replaceable></filename>
+            command, BitBake sorts out the configurations to ultimately
+            define your build environment.
+            It is important to understand that the OpenEmbedded build system
+            reads the configuration files in a specific order:
+            <filename>site.conf</filename>, <filename>auto.conf</filename>,
+            and <filename>local.conf</filename>.
+            And, the build system applies the normal assignment statement
+            rules.
+            Because the files are parsed in a specific order, variable
+            assignments for the same variable could be affected.
+            For example, if the <filename>auto.conf</filename> file and
+            the <filename>local.conf</filename> set
+            <replaceable>variable1</replaceable> to different values, because
+            the build system parses <filename>local.conf</filename> after
+            <filename>auto.conf</filename>,
+            <replaceable>variable1</replaceable> is assigned the value from
+            the <filename>local.conf</filename> file.
         </para>
     </section>