Fix: the code was actually doing a copy

cython_wrapper.pyx

@@ -14,6 +14,7 @@ cdef extern from "c_code.c":
     float *compute(int size)
 
 from libc.stdlib cimport free
+from cpython cimport PyObject, Py_INCREF
 
 # Import the Python-level symbols of numpy
 import numpy as np
@@ -70,10 +71,18 @@ def py_compute(int size):
         not copy the data allocated in C.
     """
     cdef float *array
+    cdef np.ndarray ndarray
     # Call the C function
     array = compute(size)
 
     array_wrapper = ArrayWrapper()
     array_wrapper.set_data(size, <void*> array) 
+    ndarray = np.array(array_wrapper, copy=False)
+    # Assign our object to the 'base' of the ndarray object
+    ndarray.base = <PyObject*> array_wrapper
+    # Increment the reference count, as the above assignement was done in
+    # C, and Python does not know that there is this additional reference
+    Py_INCREF(array_wrapper)
 
-    return np.array(array_wrapper)
+
+    return ndarray

test.py

@@ -2,7 +2,11 @@
 """
 # Author: Gael Varoquaux
 # License: BSD
+import numpy as np
 
 import cython_wrapper
 a = cython_wrapper.py_compute(10)
-print a
+
+print 'The array created is %s' % a
+print 'It carries a reference to our deallocator: %s ' % a.base
+np.testing.assert_allclose(a, np.arange(10))