Use python ctypes array data in cython functions

Question

I have python ctypes array. I would like to use it in cython def and cdef functions.

import ctypes
from my_cython_extention import *

class Test_Node(ctypes.Structure):
    _fields_ = [
        ("i", ctypes.c_int),
        ("f", ctypes.c_float),
    ]
my_array = (Test_Node * 10)()
my_cython_function(my_array)

How should I define cython function my_cython_function to access my_array data? Can I get my_array C++ data pointer?

Stepochkin · Accepted Answer · 2018-01-10 11:55:42Z

1

I have found an answer to the question:

cdef my_cython_function_c(
    Test_Node *arr_addr, int arr_size
):
    for i in range(arr_size):
        printf("%i\n", arr_addr.i)
        inc(arr_addr)

def my_cython_function(arr):
    my_cython_function_c(<Test_Node *><long>ctypes.addressof(arr), len(arr))

answered Jan 10, 2018 at 11:55

Stepochkin

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1 Comment

chrisb Over a year ago

To make this platform independent, instead of long, use intptr_t defined in 'stdint.h'

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