README.md

Correct include_dirs in setup.py to be whichever folder contains all of the ROS libraries. For example, [your_include_dir]/ros/ros.h should be the main ros library for C++.

Run python2 setup.py build_ext --inplace to build the program

Run python2 to enter a python environment, and type import node to start it off.

You will probably see an error message that looks something like ImportError: /file/path/to/node.so: undefined symbol: [some mangled symbol name].

You can use c++filt to try determine what it actually talking about by running echo "[mangled symbol name]" | c++filt.

For example, the problem I'm running into can be clarified with the command echo "_ZN3ros9PublisherD1Ev" | c++filt, which outputs ros::Publisher::~Publisher(), the destructor for a ros publisher. I've also had the missing symbol _Py_ZeroStruct, but c++filt can't parse it.

file.h

#include "/opt/ros/kinetic/include/ros/ros.h"
#include "/opt/ros/kinetic/include/ros/time.h"
#include "/opt/ros/kinetic/include/std_msgs/String.h"
#include <string>

ros::NodeHandle nh;
ros::Publisher pub;
int zero = 0;

void startROS() {
	ros::init(zero, 0, "testNode");
	pub = nh.advertise<std_msgs::String>("chatter", 1000);
}
bool rosOK() {
	return ros::ok();
}
void rosSpin() {
	ros::spinOnce();
}

void publish(std::string str) {
	std_msgs::String msg;
	msg.data = str;
	pub.publish(msg);
}

node.pyx

# distutils: language=c++

from libcpp.string cimport string
from libcpp cimport bool

cdef extern from "file.h":
	void startROS()
	bool rosOK()
	void rosSpin()
	void publish(string)

startROS()

while rosOK():
	publish("test")
	rosSpin()

setup.py

from distutils.core import setup
from distutils.core import Extension
from Cython.Distutils import build_ext
from Cython.Build import cythonize

ext = Extension(
	"node",
	["node.pyx"],
	language="c++",
	include_dirs=["/opt/ros/kinetic/include"]
	# libraries=[],
	# extra_link_args=[],
	# cmdclass = {'build_ext': build_ext}
	)

setup(
	ext_modules = cythonize(
		ext
	)
)