sysmo-bts
/
generic-poky
9
0
Fork 0
Code Pull Requests Releases Activity

bitbake: usermanual.xml: Add section for ?= var setting. 

(Bitbake rev: df8309c11a43a9488ca25ec114a2dd3d49b041ff)

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
This commit is contained in:
Theodore A. Roth 2009-03-02 12:08:09 -08:00 committed by Richard Purdie
parent 6ae3907433
commit bf6a4fd658
1 changed files with 5 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
bitbake/doc/manual/usermanual.xml
View File

@ -88,6 +88,11 @@ share common metadata between many packages.</para></listitem>
<varname>B</varname> = "pre${A}post"</screen></para>
<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>