[ros-users] Using $(arg) substitution

Hi,

Is there any help on how to properly use the $(arg) substitution in
launch files? I followed the example given at
http://www.ros.org/wiki/roslaunch/XML/arg but it gives me a "unused
args" error.

This is with ROS CTurtle on Ubuntu 10.10.

$ cat test.launch
<launch>
    <include file="test2.launch">
        <arg name="name" value="value"/>
    </include>
</launch>

$ cat test2.launch
<launch>
    <param name="param" value="$(arg name)"/>
</launch>

$ roslaunch test.launch
...
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

unused args [name] for include of [test2.launch]


--
Kartik