ctype_test.py

from ctypes import *


class Node(Structure):
    pass

Node._fields_ = [("next", POINTER(Node)),
                ("foo", c_int)]


class List(Structure):
    _fields_ = [("head", POINTER(Node))]

    def __init__(self, foo):
        self.head = pointer(Node(None, c_int(foo)))

    def append(self, extra_foo):
        p = self.head
        while p.contents.next:
            p = p.contents.next
        p.contents.next = pointer(extra_foo)

    def __str__(self):
        value = ''
        p = self.head
        while p:
            value += str(p.contents.foo)
            p = p.contents.next
        return value


def main():
    l = List(0)
    for x in range(1, 10):
        l.append(Node(None, c_int(x)))

    print l


if __name__ == '__main__':
    main()

A little example of using ctypes