mirror of
https://github.com/QB64-Phoenix-Edition/QB64pe.git
synced 2024-09-18 23:14:50 +00:00
67 lines
1.6 KiB
Python
67 lines
1.6 KiB
Python
r'''
|
|
This tests the '_objects' attribute of ctypes instances. '_objects'
|
|
holds references to objects that must be kept alive as long as the
|
|
ctypes instance, to make sure that the memory buffer is valid.
|
|
|
|
WARNING: The '_objects' attribute is exposed ONLY for debugging ctypes itself,
|
|
it MUST NEVER BE MODIFIED!
|
|
|
|
'_objects' is initialized to a dictionary on first use, before that it
|
|
is None.
|
|
|
|
Here is an array of string pointers:
|
|
|
|
>>> from ctypes import *
|
|
>>> array = (c_char_p * 5)()
|
|
>>> print array._objects
|
|
None
|
|
>>>
|
|
|
|
The memory block stores pointers to strings, and the strings itself
|
|
assigned from Python must be kept.
|
|
|
|
>>> array[4] = 'foo bar'
|
|
>>> array._objects
|
|
{'4': 'foo bar'}
|
|
>>> array[4]
|
|
'foo bar'
|
|
>>>
|
|
|
|
It gets more complicated when the ctypes instance itself is contained
|
|
in a 'base' object.
|
|
|
|
>>> class X(Structure):
|
|
... _fields_ = [("x", c_int), ("y", c_int), ("array", c_char_p * 5)]
|
|
...
|
|
>>> x = X()
|
|
>>> print x._objects
|
|
None
|
|
>>>
|
|
|
|
The'array' attribute of the 'x' object shares part of the memory buffer
|
|
of 'x' ('_b_base_' is either None, or the root object owning the memory block):
|
|
|
|
>>> print x.array._b_base_ # doctest: +ELLIPSIS
|
|
<ctypes.test.test_objects.X object at 0x...>
|
|
>>>
|
|
|
|
>>> x.array[0] = 'spam spam spam'
|
|
>>> x._objects
|
|
{'0:2': 'spam spam spam'}
|
|
>>> x.array._b_base_._objects
|
|
{'0:2': 'spam spam spam'}
|
|
>>>
|
|
|
|
'''
|
|
|
|
import unittest, doctest, sys
|
|
|
|
import ctypes.test.test_objects
|
|
|
|
class TestCase(unittest.TestCase):
|
|
def test(self):
|
|
failures, tests = doctest.testmod(ctypes.test.test_objects)
|
|
self.assertFalse(failures, 'doctests failed, see output above')
|
|
|
|
if __name__ == '__main__':
|
|
doctest.testmod(ctypes.test.test_objects)
|