What is the cause of ROS2 XML launch substitution error "Unknown substitution: arg"?
I am trying to pass a yaml file as a launch argument to use as parameters for a node and I am getting the following error:
[ERROR] [launch]: Caught exception in launch (see debug for traceback): Caught exception when trying to load file of format [xml]: Error trying to process rule "substitution":
Unknown substitution: arg
Below is how I implemented passing the yaml as an argument.
<arg name="config_file" default="$(find-pkg-share nusim)/config/basic_world.yaml"/> <node pkg="nusim" exec="nusim"> </node>
Everything I have seen on the ROS documentation uses this format for substituting arguments so I am unsure why it is an unknown substitution.
The only difference that I am seeing between mine and the ROS docs is that they do something like:
<param name="foo" value="$(arg my_foo)" />
From this I tried to give it a name but it still says unknown substitution.
Does anyone have any idea what could be the cause of this error?
