ctype for array of pointers

ctype_test.c

#include "stdio.h"

// mac : gcc  -dynamiclib -o ctype_test.dylib ctype_test.c

/*
	two dimensional pointer
 */

void ctype_test(void *pa, int num, int size)
{
    printf(" %p\n", pa);
    int **tmp = (int **)pa;
    for (int i = 0; i < num; i ++ )
    {
        for (int j = 0; j < size; j++)
        {
            tmp[i][j] = i * 10 + j;
        }
    }
}

/*
	one dimensional pointer
 */
int set(int *a, int size)
{
    printf("%p\n", a);
    for (int i = 0; i < size; i++)
    {
        a[i] = i;
    }
}

int add(int a, int b)
{
    return (a + b);
}

ctype_test.py

from ctypes import *
import numpy as np

################################### add ############################################
dylib = CDLL('ctype_test.dylib')
print(dylib.add(12,14))
################################### pointer ############################################
d = np.zeros(10,dtype=np.uint32)
print(d)
dylib.set(d.ctypes.data_as(POINTER(c_int32)), len(d))
print(d, d.ctypes.data_as(POINTER(c_int32)), hex(id(d.ctypes.data_as(POINTER(c_int32)))))
################################### array of pointers ############################################
num = 6
size = 7
data = []
for i in range(num):
	data.append(np.zeros(size,dtype=np.uint32))
arpDestBuffers = (POINTER(c_int32) * num)()
print(arpDestBuffers, hex(id(arpDestBuffers)), sizeof(arpDestBuffers))
arpDestBuffers[:] = [d.ctypes.data_as(POINTER(c_int32)) for d in data]
dylib.ctype_test(arpDestBuffers, num, size)

for d in data:
	print(d)
###############################################################################

result

➜  Desktop python ctype_test.py                             
26
[0 0 0 0 0 0 0 0 0 0]
0x7fe052600910
[0 1 2 3 4 5 6 7 8 9] <__main__.LP_c_int object at 0x10897a6a8> 0x107c4f510
<__main__.LP_c_int_Array_6 object at 0x10897a6a8> 0x10897a6a8 48
 0x7fe0548142d0
[0 1 2 3 4 5 6]
[10 11 12 13 14 15 16]
[20 21 22 23 24 25 26]
[30 31 32 33 34 35 36]
[40 41 42 43 44 45 46]
[50 51 52 53 54 55 56]