PYTHON setup.py build_ext --inplace
PYTHON -c "import foo"
PYTHON -c "import a"
######## setup.py ########
from Cython.Build import cythonize
from distutils.core import setup
setup(
ext_modules = cythonize("*.pyx"),
)
######## foo.pxd ########
cdef void bar() except *
######## foo.pyx ########
cdef extern from "bar_impl.c":
void bar() except *
######## bar_impl.c ########
static void bar() {}
######## a.pyx ########
from foo cimport bar