PyWin SendMessage

g.franzkowiak g.franzkowiak at onlinehome.de
Thu Sep 29 21:18:45 CEST 2005


Thomas Heller schrieb:
> "g.franzkowiak" <g.franzkowiak at onlinehome.de> writes:
> 
> 
>>Thomas Heller schrieb:
>>
>>>"g.franzkowiak" <g.franzkowiak at onlinehome.de> writes:
>>>
>>>
>>>
>>>>Hello everybody,
>>>>
>>>>I've tryed to use an interprocess communication via
>>>>SendMessage on Windows.
>>>>Unfortunately, nothing goes on
>>>>
>>>>#########################################################################
>>>>#! /usr/bin/env python
>>>>
>>>>import win32api, win32ui, win32con
>>>>import struct, array
>>>>
>>>>"""
>>>>typedef struct tagCOPYDATASTRUCT {  // cds
>>>>   DWORD dwData;
>>>>   DWORD cbData;
>>>>   PVOID lpData;
>>>>} COPYDATASTRUCT;
>>>>"""
>>>>
>>>>def packCopyData(nNum, sString):
>>>>   int_buffer  = array.array("L",[nNum])
>>>>   char_buffer = array.array('c', sString)
>>>>   int_buffer_address  = int_buffer.buffer_info()[0]
>>>>   char_buffer_address = char_buffer.buffer_info()[0]
>>>>   char_buffer_size    = char_buffer.buffer_info()[1]
>>>>   copy_struct = struct.pack("pLp",        # dword*, dword, char*
>>>>                             int_buffer_address,
>>>>                             char_buffer_size,
>>>>                             char_buffer)
>>>>   return copy_struct
>>>
>>>
>>>After packCopyData(...) returns, the arrays are destroyed, which will
>>>probably void their contents.  You must keep them alive until you don't
>>>need the COPYDATASTRUCT instance any longer.  For this kind of stuff,
>>>ctypes may be easier to use than pywin32.
>>>
>>>Thomas
>>
>>Hmm, have read something in <<http://aspn.activestate.com>>
>>and the script changed to this:
>>
>>#---------------------------------------------------------
>>#! /usr/bin/env python
>>
>>import win32api, win32ui, win32con, win32gui
>>import struct, array
>>from ctypes import *
>>
>>"""
>>typedef struct tagCOPYDATASTRUCT {  // cds
>>    DWORD dwData;
>>    DWORD cbData;
>>    PVOID lpData;
>>} COPYDATASTRUCT;
>>"""
>>
>>class COPYDATATYPE(Structure):
>>    _fields_ = [("nNum",   c_ulong),
>>                ("szData", c_char_p)]
>>
>>class COPYDATASTRUCT(Structure):
>>    _fields_ = [("dwData", c_ulong),
>>                ("cbData", c_ulong),
>>                ("lpData", POINTER(COPYDATATYPE))]
>>
>># get the window handle
>>hwnd = win32ui.FindWindow(None, "target window")
>>
>># print just for fun
>># ##print hwnd
>>
>># prepare copydata structure for sending data
>>cpyData = COPYDATATYPE(1, '1')
>>cds = COPYDATASTRUCT(c_ulong(1),
>>                     c_ulong(sizeof(cpyData)),
>>                     pointer(cpyData))
>>
>># try to send a message
>>win32api.SendMessage(hwnd,
>>                     win32con.WM_COPYDATA,
>>                     0,
>>                     pointer(cds))
>>
>>#---------------------------------------------------------
>>and the message for the last line is:
>>==> TypeError: an integer is required"
>>
>>This message comes with "pointer(cds)" and with "addressof(cds)"
> 
> 
> That error refers to the first argument - win32ui.FindWindow returns a
> PyCWnd object, which is not accepted by win32api.SendMessage.
> Changing this brings you one step further.  win32api.SendMessage accepts
> an integer for the last element, so addressof(cds) should work now.
> 
> win32gui.SendMessage is more tolerant in what it accepts as 4th
> argument, according to the error message you get when you try it it
> expects a string, a buffer, or an integer.  So you could use addressof()
> or pointer(), what you like best.
> 
> Thomas

Hi Thomas,

crazy, operates :-))
Only 'addressof' is possible and
merely the data types on the receiver side are not correct.
I want use an int and char[256], must play...

Thanks
gerd



More information about the Python-list mailing list