When pywinauto uses “ctypes” to call the same system function with other modules ，it will cause the ctypes.ArgumentError

Steps to Reproduce the Problem

1. import pywinauto
2. import other module which using ctypes to call the same system function

Actual Behavior

return bool(ctypes.windll.user32.IsWindowVisible(ctypes.c_void_p(handle)))
ctypes.ArgumentError: argument 1: <class 'TypeError'>: wrong type

Expected Behavior

If I delete the the argtypes and restype in win32functions.py， for example

IsWindowVisible.argtypes = [win32structures.HWND]
IsWindowVisible.restype = win32structures.BOOL ，

everything seems to go well.

Short Example of Code to Demonstrate the Problem

from pywinauto.application import Application
import uiautomation as auto
from data.setting import Setting

window = auto.WindowControl(AutomationId="mywindowautoid",Name="mywindowname",searchDepth =1)
window.SetActive()
app = Application(backend="uia").connect(path=Setting.exepath)
print(app.is_process_running())

Specifications

• Pywinauto version: the lastest version 0.6.6
• Python version and bitness: 3.7.2 and 32bit
• Platform and OS: Win10

[airelil]

Pywinauto sets up the return type of GetWindow to wintypes.HWND as per https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getwindow The xlwings problem seems to be due to this line in _xlwings.py: https://github.com/xlwings/xlwings/blob/4a51d73b87af3820fc686b402e65e0c843e9d63c/xlwings/_xlwindows.py#L300 because the c_void_p is casted to Python long type instead of integer returned by ctypes restype by default. Limiting restype to integer is dangerous, especially on 64-bit OS, because HWND can exceed the integer type max size, which I believe is 32-bits for Python 2.7 (see: sys.maxint)

[shoval]

I encountered the same problem using the xlwings package.

How to reproduce

1. Open some Excel workbook (one or more, it doesn’t matter)
2. Run the code below once - it should print out the names of the open workbooks
3. Uncomment the first row and run again - now it should raise an attribute error

# import pywinauto
import xlwings as xw
print xw.books

Insights

I managed to track the problem to the following lines in win32functions.py:

GetWindow = windll.user32.GetWindow
GetWindow.restype = wintypes.HWND

Overriding GetWindow.restype, which is global, is what causes the problem.

Specifications

• Pywinauto version: 0.6.7
• Python version: 2.7.15 (64bit)
• Platform and OS: Win7