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authorTheodore A. Roth <taroth@gmail.com>2009-03-02 12:08:09 -0800
committerRichard Purdie <rpurdie@linux.intel.com>2010-01-21 10:57:28 +0000
commitdf8309c11a43a9488ca25ec114a2dd3d49b041ff (patch)
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parent74979370eff1a8b7b7f8a4ca146ad9d4bf83c9af (diff)
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usermanual.xml: Add section for ?= var setting.
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
Diffstat (limited to 'doc')
-rw-r--r--doc/manual/usermanual.xml5
1 files changed, 5 insertions, 0 deletions
diff --git a/doc/manual/usermanual.xml b/doc/manual/usermanual.xml
index cdd05998..c3403449 100644
--- a/doc/manual/usermanual.xml
+++ b/doc/manual/usermanual.xml
@@ -89,6 +89,11 @@ share common metadata between many packages.</para></listitem>
<para>This results in <varname>A</varname> containing <literal>aval</literal> and <varname>B</varname> containing <literal>preavalpost</literal>.</para>
</section>
<section>
+ <title>Setting a default value (?=)</title>
+ <para><screen><varname>A</varname> ?= "aval"</screen></para>
+ <para>If <varname>A</varname> is set before the above is called, it will retain it's previous value. If <varname>A</varname> is unset prior to the above call, <varname>A</varname> will be set to <literal>aval</literal>.</para>
+ </section>
+ <section>
<title>Immediate variable expansion (:=)</title>
<para>:= results in a variable's contents being expanded immediately, rather than when the variable is actually used.</para>
<para><screen><varname>T</varname> = "123"