使用ctypes windll卸载64位dll时出错 [英] error when unload a 64bit dll using ctypes windll

问题描述

我发现这里有几篇关于使用ctypes卸载dll的文章，我完全按照据说的方式从ctypes import工作
*

i found there are several posts here about unloading a dll using ctypes, and i followed exactly the way said to be working from ctypes import *

file = CDLL('file.dll')

# do some stuff here

handle = file._handle # obtain the DLL handle

windll.kernel32.FreeLibrary(handle)

但是我在python 64位，并且我的dll也针对x64进行了编译，我从上面的最后一行得到了一个错误：

however, i am on python 64 bit and my dll is also compiled for x64, and i got an error from the last line above saying:

argument 1: <class 'OverflowError'>: int too long to convert

，我检查了句柄是'8791681138688'的long int（int64），那么这是否意味着windll.kernel32仅处理int32句柄？ Google搜索显示kernal32也适用于64位Windows。那么我应该如何处理呢？

and i checked the handle to be a long int (int64) of '8791681138688', so does that mean windll.kernel32 only deals with int32 handle? Google search shows kernal32 is also for 64bit windows. how should i deal with this then?

推荐答案

FreeLibrary 需要一个句柄，已定义作为C void * 指针。请参考 Windows数据类型。在函数指针的 argtypes 中进行设置：

FreeLibrary takes a handle, defined as a C void * pointer. Refer to Windows Data Types. Set this in the function pointer's argtypes:

import ctypes
from ctypes import wintypes

kernel32 = ctypes.WinDLL('kernel32', use_last_error=True)    
kernel32.FreeLibrary.argtypes = [wintypes.HMODULE]

Python int 或 long （在Python 3中重命名为 int ）为C long ，随后将其转换为C int 。 Microsoft即使在64位Windows上也使用32位 long ，这就是为什么转换会引发 OverflowError 的原因。

The default conversion of a Python int or long (renamed int in Python 3) is to a C long, which is subsequently cast to a C int. Microsoft uses a 32-bit long even on 64-bit Windows, which is why the conversion raises OverflowError.

在具有64位长（即几乎所有其他64位OS）的平台上，一个没有定义函数的 argtypes 的Python整数指针实际上可能会隔离进程。初始转换为 long 的效果很好，因为它的大小与指针相同。但是，随后强制转换为32位C int 可能会无声地截断该值。

On platforms that have a 64-bit long (i.e. pretty much every other 64-bit OS), passing a pointer as a Python integer without defining the function's argtypes may actually segfault the process. The initial conversion to long works fine because it's the same size as a pointer. However, subsequently casting to a 32-bit C int may silently truncate the value.

这篇关于使用ctypes windll卸载64位dll时出错的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！