PYTHON setup.py build_ext --inplace

PYTHON -c "import a"

######## setup.py ########

from Cython.Build import cythonize

from distutils.core import setup

# Add ./site-packages to sys.path

from os.path import realpath

import sys

sys.path.append(realpath('site-packages'))

setup(

  ext_modules = cythonize("*.pyx"),

)

######## site-packages/b/__init__.py ########

######## site-packages/b/other.pxd ########

cdef extern from "foo.c":

    int foo(int)

######## site-packages/b/foo.c ########

static int foo(int a)

{

    return a * a;

}

######## a.pyx ########

from b.other cimport foo

print foo(10)

cimport b.other

print b.other.foo(10)