README.md

Python binding tools for C++

This package provides some tools to facilitate the generation of python bindings for C++ code, based on pybind11.

Automatic type conversion for ROS message types

Conversion between native C++ and python types is performed via ROS message serialization and deserialization, which is implemented via C++ templates. It suffices to include:

#include <py_binding_tools/ros_msg_typecasters.h>

The PoseStamped message from the geometry_msgs package also accepts a single string as an argument. In this case, the string is interpreted as the header.frame_id field of the message and the pose becomes the identity transform. To use this extension, include the following header instead:

#include <py_binding_tools/geometry_msg_typecasters.h>

C++ ROS initialization

C++ and Python use their own ROS implementations (rospy and roscpp). Thus, it is necessary to initialize ROS in the C++ domain additionally to the Python domain before calling any ROS-related functions from wrapped C++ functions or classes. To this end, the package provides the python function roscpp_init() and the C++ class ROScppInitializer. The latter is intended to be used as a base class for your python wrapper classes:

class FooWrapper : protected ROScppInitializer, public Foo {
	// ...
};

to ensure that the ROS infrastructure is initialized before usage in the wrapped C++ class. Ensure to list ROScppInitializer as the first base class, if ROS functionality is required in the constructor already!

ROScppInitializer registers an anonymous C++ ROS node named python_wrapper_xxx. If you need a specific node name or if you want to pass remappings, use the manual initialization function roscpp_init(name="", remappings={}, options=0) instead, which effectively calls ros::init with the given arguments. Note, that an empty name will map to the above-mentioned node name python_wrapper_xxx.