<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 RELEASE=bad_value foo.o</userinput>

scons: *** Error converting option: 'RELEASE'
Invalid value for boolean variable: 'bad_value'
File "/home/my/project/SConstruct", line 3, in &lt;module&gt;
</screen>
