[bitbake-devel] [PATCH] Documentation: Add a couple examples to conditional data.

[Robert P. J. Day]

Signed-off-by: Robert P. J. Day <rpjday at crashcourse.ca>

---

  i think having a couple real-life examples here would make a huge
difference.

diff --git a/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml b/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml
index a9f5072..e433d85 100644
--- a/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml
+++ b/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml
@@ -372,6 +372,23 @@
                         You select the os-specific version of the <filename>TEST</filename>
                         variable by appending the "os" override to the variable
                         (i.e.<filename>TEST_os</filename>).
+                        </para>
+
+                        <para>
+                            As a practical example, the following lines from
+                            one of the Linux kernel recipe files will first set
+                            the kernel branch variable <filename>KBRANCH</filename>
+                            to a default value, then conditionally override that
+                            value based on the architecture of the build:
+                        <literallayout class='monospaced'>
+    KBRANCH = "standard/base"
+    KBRANCH_qemuarm  = "standard/arm-versatile-926ejs"
+    KBRANCH_qemumips = "standard/mti-malta32"
+    KBRANCH_qemuppc  = "standard/qemuppc"
+    KBRANCH_qemux86  = "standard/common-pc/base"
+    KBRANCH_qemux86-64  = "standard/common-pc-64/base"
+    KBRANCH_qemumips64 = "standard/mti-malta64"
+                        </literallayout>
                         </para></listitem>
                     <listitem><para><emphasis>Appending and Prepending:</emphasis>
                         BitBake also supports append and prepend operations to
@@ -385,6 +402,18 @@
                         </literallayout>
                         In this example, <filename>DEPENDS</filename> becomes
                         "glibc ncurses libmad".
+                        </para>
+
+                        <para>
+                            Again using a kernel recipe file as an example, the
+                            following lines will conditionally append to the
+                            <filename>KERNEL_FEATURES</filename> variable based
+                            on the architecture:
+                        <literallayout class='monospaced'>
+    KERNEL_FEATURES_append = " ${KERNEL_EXTRA_FEATURES}"
+    KERNEL_FEATURES_append_qemux86=" cfg/sound.scc cfg/paravirt_kvm.scc"
+    KERNEL_FEATURES_append_qemux86-64=" cfg/sound.scc cfg/paravirt_kvm.scc"
+                        </literallayout>
                         </para></listitem>
                 </itemizedlist>
             </para>

-- 

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Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
LinkedIn:                               http://ca.linkedin.com/in/rpjday
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