Cython 0.16 C++ Demo

.gitignore

*.so
_demo.cpp
build

_demo.pyx

# distutils: language = c++
# distutils: sources = demo.cpp

cdef extern from "demo.h" namespace "demo":
    cdef int test(float*, int)

import numpy as np
cimport numpy as cnp

def func(cnp.ndarray[cnp.float32_t, ndim=1] arr,
         size=1,
        ):

    assert arr.dtype == 'float32'
    ptr = arr.data
    return test(<float*>arr.data, <Py_ssize_t>size)

demo.cpp

#include <iostream>

#include "demo.h"

using namespace std;

int demo::test(float* arr, int size)
{
    int i;
    for(i=0; i < size; ++i)
        cout << i << ":" << ((float*)arr)[i] << endl;
    return i;
}

demo.h

namespace demo {
    int test(float* arr, int size);
}

setup.py

from distutils.core import setup
from distutils.extension import Extension
from Cython.Distutils import build_ext

import numpy as np


setup(
    ext_modules=[
        Extension("_demo",
                  sources=["_demo.pyx", "demo.cpp"],
                  language="c++",
                  include_dirs=[np.get_include()],
                 ),

    ],
    cmdclass={'build_ext': build_ext}
    )


import _demo

arr = np.random.randn(10).astype('f')
print _demo.func(arr, size=len(arr))