<screen xmlns="http://www.scons.org/dbxsd/v1.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.scons.org/dbxsd/v1.0 http://www.scons.org/dbxsd/v1.0/scons.xsd">% <userinput>scons -Q COLOR=magenta foo.o</userinput>

scons: *** Invalid value for enum variable 'COLOR': 'magenta'. Valid values are: ('red', 'green', 'blue')
File "/home/my/project/SConstruct", line 10, in &lt;module&gt;
</screen>
