cleanup of C arrays in Cython

arr_base.py

cdef class _finalizer:
    cdef void *_data
    def __dealloc__(self):
        print "_finalizer.__dealloc__"
        if self._data is not NULL:
            free(self._data)

            
cdef void set_base(cnp.ndarray arr, void *carr):
    cdef _finalizer f = _finalizer()
    f._data = <void*>carr
    cnp.set_array_base(arr, f)            

    
def make_matrix(int nrows, int ncols):
    cdef float *mat = make_matrix_c(nrows, ncols)
    cdef float[:, ::1] mv = <float[:nrows, :ncols]>mat
    cdef cnp.ndarray arr = np.asarray(mv)
    set_base(arr, mat)
    return arr    
  
  
#setup  

setup.py

from distutils.core import setup, Extension
from Cython.Build import cythonize
from numpy import get_include

ext = Extension("numpy_cleanup", ["numpy_cleanup.pyx"],
                include_dirs=['.', get_include()])

setup(name="numpy_cleanup",
      ext_modules = cythonize(ext))




#python setup.py build_ext -i
$ ipython --no-banner

In [1]: import numpy_cleanup

In [2]: arr = numpy_cleanup.make_matrix(100, 100)
In [3]: arr.base
Out[3]: <numpy_cleanup._finalizer at 0x100284eb8>
In [4]: %reset
Once deleted, variables cannot be recovered. Proceed (y/[n])? y
_finalizer.__dealloc__