Windows and Subclassing - 'OverflowError': int too long to convert

[Eryk Sun]

On 7/28/20, Eko palypse <ekopalypse at gmail.com> wrote:
>
> Now when I get this error the message I receive in this situation is always
> like this.
>
> hWnd=197364, msg=20, wParam=*18446744072652653190*, lParam=0
>
> Traceback (most recent call last):
>   File "_ctypes/callbacks.c", line 237, in 'calling callback function'
>   File "<string>", line 121, in new_scintilla2_proc
> ctypes.ArgumentError: argument 4: <class 'OverflowError'>: int too long to
> convert

Can you provide a more complete example of how you're calling
CallWindowProcW in new_scintilla2_proc? It seems like a function
pointer is being called that doesn't have argtypes defined. For
example:

    >>> user32 = ctypes.WinDLL('user32', use_last_error=True)
    >>> user32.CallWindowProcW(None, None, 0x14, 18446744072652653190, 0)
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    ctypes.ArgumentError: argument 4: <class 'OverflowError'>: int too
long to convert

Perhaps in new_scintilla2_proc you're using a different instance of
ctypes.WinDLL, or you switched to using ctypes.windll.user32. I
recommend avoiding the global ctypes.LibraryLoader instances --
ctypes.cdll, ctypes.windll, and ctypes.oledll -- because using them
leads to conflicts with other libraries, but you do need to use a
single instance of ctypes.WinDLL for your user32 function prototypes,
imported from a common module.