Segmentation fault when using boost::numpy::ndarray

boost, c++, numpy, python

Solution

I knew it was something simple. I needed to add these two lines:

Py_Initialize();
boost::numpy::initialize();

as explained : here seg fault results after any attempt to use `boost::numpy::ndarray` if the above lines are not ran.

Therefore: my file becomes:

#include <iostream>
#include <boost/python.hpp>
#include <boost/numpy.hpp>


void say_hello(boost::numpy::ndarray& my_array)
//void say_hello(int x) This works fine
{
  std::cout<<"Hello"<<std::endl;
}

BOOST_PYTHON_MODULE(hello_ext)
{
    using namespace boost::python;
    Py_Initialize();
    boost::numpy::initialize();
    def("say_hello", say_hello);
}

Problem

I am getting what I think is a strange seg fault when I am trying to pass `boost::numpy::ndarray` as an argument: ``` #include <iostream> #include <boost/python.hpp> #include <boost/numpy.hpp> void say_hello(boost::numpy::ndarray& my_array) //void say_hello(int x) This works fine { std::cout<<"Hello"<<std::endl; } BOOST_PYTHON_MODULE(hello_ext) { using namespace boost::python; def("say_hello", say_hello); } ``` I know the example is silly, but I should not be getting a seg fault there, and this is the smallest example I was able to reduce the problem to. Maybe I need to specify the `ndarray` type or number of dimensions, but I could not find any documentation on it. I was looking at this, but it didn't seem very helpful. My gut feeling is I am missing something simple, but I just don't see it. When I run this: ``` In [1]: from hello_ext import * In [2]: import numpy as np In [3]: say_hello(np.array([3,4,5])) Segmentation fault (core dumped) ``` My Makefile: ``` PYTHON_VERSION = 2.7 PYTHON_INCLUDE = /usr/include/python$(PYTHON_VERSION) BOOST_INC = /usr/include BOOST_LIB = /usr/lib TARGET = hello_ext $(TARGET).so: $(TARGET).o g++ -std=c++11 -shared -Wl,--export-dynamic $(TARGET).o -L$(BOOST_LIB) -lboost_python -lboost_numpy -L/usr/lib/python$(PYTHON_VERSION)/config -lpython$(PYTHON_VERSION) -o $(TARGET).so $(TARGET).o: $(TARGET).cpp g++ -std=c++11 -I$(PYTHON_INCLUDE) -I$(BOOST_INC) -fPIC -c $(TARGET).cp ```

Original source