[ctypes-users] How to cast a pointer to an LPARAM?

[Roger E. <r....@eu...>]

Any help with the following would be highly appreciated:
How do I translate the following (working) piece of code::

import win32gui, win32api, win32con
import struct, array

VRC_MAGIC = 0x53445256
VRC_SHOW = 1

# vrcshow structure
show = struct.pack('L', 1)

#vrcheader structure for use with vrcshow structure
#the Long in the vrcshow structure was packed into 4 characters
header0 = struct.pack('LL4s', VRC_MAGIC, VRC_SHOW, show)
header1 = array.array('c', header0)
header2 = header1.buffer_info()

#copydata structure for use with vrcshow structure
cd0 = struct.pack('LLP', VRC_MAGIC, header2[1], header2[0])
cd1 = array.array('c', cd0)
cd2 = cd1.buffer_info()

hViridis = win32gui.FindWindow('VIRIDIS_DISPATCHER', None)
if hViridis:
   win32api.SendMessage(hViridis, win32con.WM_COPYDATA, 0, cd2[0])



into code that uses ctypes (windows-0.4.1)? I've got this now::

import win32gui, win32api, win32con
from ctypes import *

DWORD = c_ulong
BYTE = c_ubyte

VRC_MAGIC = c_ulong(0x53445256)
VRC_SHOW = c_ulong(1)

class VRCSHOW(Structure):
    _fields_ = [("Show", DWORD)]

class VRCHEADER(Structure):
    _fields_ = [("Magic", DWORD),
                ("Command", DWORD),
                ("Data", VRCSHOW)]

class COPYDATASTRUCT(Structure):
    _fields_ = [("dwData", DWORD),
                ("cbData", DWORD),
                ("lpData", POINTER(VRCHEADER))]
                

str_vrcshow = VRCSHOW(VRC_SHOW)
str_vrcheader = VRCHEADER(VRC_MAGIC, VRC_SHOW, str_vrcshow)
data = COPYDATASTRUCT(VRC_MAGIC, DWORD(sizeof(str_vrcheader)),
pointer(str_vrcheader))

hViridis = win32gui.FindWindow('VIRIDIS_DISPATCHER', None)
if hViridis:
   win32api.SendMessage(hViridis, win32con.WM_COPYDATA, 0, pointer(data))




but running it gives me a TypeError::
Traceback (most recent call last):
  File "Z:\src\py\sc.py", line 31, in ?
    win32api.SendMessage(hViridis, win32con.WM_COPYDATA, 0, pointer(data))
TypeError: an integer is required


The doc of viridis_dispatcher tells me to call SendMessage like this::
SendMessage(hViridis, WM_COPYDATA, (WPARAM)hWnd, (LPARAM)pData);

I'm trying to do this translation because as a next step, my VRCHEADER
structure needs to be able to contain various other structures besides
VRCSHOW.

Thanks in advance,
Roger