ctypes：从任意整数构造指针 [英] ctypes: construct pointer from arbitrary integer

问题描述

出于低级目的，我需要从任意地址（以整数形式给出）构造ctypes指针。例如：

For low-level purposes, I need to construct a ctypes pointer from an arbitrary address, given as an integer. For instance:

INTP = ctypes.POINTER(ctypes.c_int)
p = INTP(0x12345678) # i *know* this is the address

但是所有此类尝试都会导致

But all such attempts result in

TypeError: expected c_long instead of int

有什么我可以克服的吗？如果有人想知道为什么我需要这样做，可以这样做是为了从 win32文件中提取 OVERLAPPED 结构。PyOVERLAPPED，

Is there anything I can do to overcome this? In case someone wonders why I need this, it's done so as to extract the OVERLAPPED struct from a win32file.PyOVERLAPPED, for integrating ctypes-exposed functions with win32file wrapped APIs.

谢谢，

-Tomer

Thanks,
-Tomer

推荐答案

您可以使用 ctypes.cast（addr，type）。我将扩展您的示例以通过已知对象获取地址，以演示：

You can use ctypes.cast(addr, type). I'll extend your example to acquire an address via a known object, to demonstrate:

INTP = ctypes.POINTER(ctypes.c_int)
num = ctypes.c_int(42)
addr = ctypes.addressof(num)
print 'address:', addr, type(addr)
ptr = ctypes.cast(addr, INTP)
print 'pointer:', ptr
print 'value:', ptr[0]

输出：

address: 4301122528 <type 'int'>
pointer: <__main__.LP_c_int object at 0x1005decb0>
value: 42

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