zero terminated dynamic array as return value in Python

Question

From python I am trying to use c function that returns dynamically allocated zero terminated array of integers:

int* my_func(void)
{
    int i;
    int *ret = (int*)malloc((LEN + 1) * sizeof(int));

    for (i = 0; i < LEN; i++) ret[i] = 1;
    ret[LEN] = 0

    return ret;
}

I need something like

from ctypes import *

l = cdll.LoadLibrary("lib.so")
my_func = l.my_func
my_func.restype = c_int * LEN

for x in my_func(): print x

The problem is that LEN is unknown in python code, I need to read the array till first zero element.

Answer 1

Haven't really worked with ctypes yet, but what about:

from ctypes import *

l = cdll.LoadLibrary("lib.so")
my_func = l.my_func
my_func.restype = POINTER(c_int)

i = 0;
rv = my_func()
while rv[i]:
    print rv[i]
    i += 1