找不到Python LoadLibrary

Question

我正在尝试从Python加载一个.dll。我在VisualStudio2017预览中使用Python3.0.17114.1。我收到一个错误，说"NameError: name LoadLibrary是未定义的“。

下面是一个代码片段(请注意，theDll是完美的)：

import ctypes
from ctypes.util import find_library
from ctypes import LibraryLoader
from ctypes.util import find_library    
theDll = find_library('DsiLibrary_dll')
dsi_lib  = LoadLibrary(theDll)

所以我读到了LoadLibrary，有几种不同的方法。我尽我所能：

cdll.LoadLibrary(theDll)
CDLL.LoadLibrary(theDll)
ctypes.CDLL.LoadLibrary(theDll)
ctypes.LoadLibrary(theDll)

我是Python的新手，所以我可能犯了一些愚蠢的错误。谁能提个建议吗？

Answer 1

您可以这样访问LoadLibrary：

import ctypes
from ctypes import cdll 
from ctypes.util import find_library    
theDll = find_library('DsiLibrary_dll')
lib = cdll.LoadLibrary(theDll)
# do stuff with lib

C类型文档

在Linux上，需要指定文件名(包括加载库的扩展名)，因此不能使用属性访问来加载库。应该使用dll加载器的LoadLibrary()方法，或者通过调用构造函数：来创建CDLL实例来加载库。从ctype导入* >>> cdll.LoadLibrary("libc.so.6") >>> libc = CDLL("libc.so.6") >>> libc >>>

Answer 2

在Python3.10.2 Win10 PC上使用Python3.10.2 x64处理同样的问题，花了两天时间。

简单的python代码：

导入os导入sys导入ctype

aqui = os.getcwd() print(aqui) os.add_dll_directory(aqui)

if os.path.exists(“LibFT260.dll”)：打印(“找到LibFT260.dll.”)其他:打印(“未能找到LibFT260.dll.”)退出()

ft = ctypes.windll.LoadLibrary('LibFT260.dll')

打印(ft.FT260_GetChipVersion)

Error line:

> ft = ctypes.windll.LoadLibrary('LibFT260.dll') with or w/o '.dll' suffix.
        
I put `LibFT260.dll` in the working directory (where I call the Python script) and the code adds that path to the os.add_dll_directory.  These were the 2
major fixes mentioned on the internet; neither worked.

[FYI:  The only ctypes library load statement that would work was 
ft = ctypes.WinDLL('LibFT260.dll', winmode = 1)
Microsoft LoadLibraryEx docs say not to use winmode = 1, it is only for backwards compatibility, so I changed to winmode = 48 which was suggested as one alternative.
(I never tried None, but 0 always failed, all other non-zero worked.)]

I ran the exact same program above on a 2nd PC and the LoadLibrary() function worked!

Details and the solution:

机器2 LoadLibrary()工作

联想P53s x64

Win10 21H2 build 19044.1526

Python3.9.0 (x64)

机器1 LoadLibrary()不工作

联想W530 x64

Win10 20H2 build 19042.1586

Python3.10.2 (x64)

已经尝试过的Python3.9.0 (x64)仍然无法工作。

Then I noticed many Visual C++ differences between the machines.  
The P53s had a more Visual C++ versions installed.
When I matched those versions on the W530 the code above worked on Machine 1.

I don't know which versions I had and which I added new, but this list worked:
(I have both the x64 & the x86 versions of all listed below on Machine 1 now.)   

Microsoft C++ 2005可再发行版(MFC安全更新)

2008版(Ver 9.0.30729.6161)

2010年版(Ver 10.0.40219)

2013年版(Ver 12.0.40664)

版2015-2022 (Ver 14.31.31103)

All of these version were still available from Microsoft on March 16, 2022.