I keep getting this error: #warning "Using deprecated NumPy API, disable it by #defining NPY_NO_DEPRECATED_API" and a bunch of undefined variables when comping cython code with numpy I am new to cython and numpy and I am having trouble getting a *.pyx extension to compile with this in the header: from __future__ import division import numpy as np cimport numpy as np DTYPE = np.int ctypedef np.int_t DTYPE_t I complie to C code using: cython -a montcarl.pyx And it seems to work fine. I then attempt to compile using: gcc -I /Developer/SDKs/MacOSX10.6.sdk/System/Library/Frameworks/ Python.framework/Versions/2.6/include/python2.6 -I /usr/local/lib/ python2.7/site-packages/numpy/core/include -shared -pthread -fPIC - fwrapv -O2 -fno-strict-aliasing -o montcar.so montcarl.c And I get a bunch of undefined variables: spoust-m:old spoust$ gcc $CFLAGS -o montcar.so montcarl.c In file included from /usr/local/lib/python2.7/site-packages/numpy/ core/include/numpy/ndarraytypes.h:1965, from /usr/local/lib/python2.7/site-packages/numpy/ core/include/numpy/ndarrayobject.h:17, from /usr/local/lib/python2.7/site-packages/numpy/ core/include/numpy/arrayobject.h:14, from montcarl.c:225: /usr/local/lib/python2.7/site-packages/numpy/core/include/numpy/ npy_deprecated_api.h:11:2: warning: #warning "Using deprecated NumPy API, disable it by #defining NPY_NO_DEPRECATED_API" Undefined symbols: "_PyLong_AsLong", referenced from: ___Pyx_PyInt_AsLong in ccvkIDLQ.o ___Pyx_PyInt_AsLong in ccvkIDLQ.o ... Any ideas on how to get this to compile and how to get rid of these numpy undefined variables? The cython guys directed me here.