Parse ROS CLI arguments (rqt_gui_cpp)

[jacobperron]

We are not parsing any user-provided command-lines arguments for ROS configuration:

rqt/rqt_gui_cpp/src/rqt_gui_cpp/roscpp_plugin_provider.cpp

Lines 90 to 96 in 5af2ce3

	int argc = 0;
	char** argv = 0;
	// Initialize any global resources needed by the middleware and the client library.
	// This will also parse command line arguments one day (as of Beta 1 they are not used).
	// You must call this before using any other part of the ROS system.
	// This should be called once per process.

I don't think the same issue exists for Python code, since by default rclpy.init() will look at sys.argv, and we're using defaults:

rqt/rqt_gui_py/src/rqt_gui_py/ros_py_plugin_provider.py

Line 80 in 5af2ce3

rclpy.init()

This prevents us from passing ROS parameters, remaps, and other ROS args when starting rqt apps. For example, it prevents us from using the QoS overrides feature, which requires that we set parameters at startup.

Supporting CLI args may require changes in qt_gui_core: https://github.com/ros-visualization/qt_gui_core