Hi.

I hope I'm in the good thing to expose my problem...
I try to make a script in Python working under ControlDesk, a dSpace 
simulator.
In this script I call an ActiveX application given by an external 
software, System Monitor, to get some information from my ECU (Engine 
Control Unit).

I can access to the ActiveX, I can call functions but only ones which 
don't need output argument.
When I use functions which need only input argument, it's working 
perfectly.
If I want to use functions which need some output argument, I have a 
message error from Python...

========================================================================
Here is an example of a working script:
***************************************

import os
import win32com.client

if __name__ == '__main__':
    print ""
    Kit = "C:\\U\\TNR_MES_2009\\THR2RAT11BA01.m"
    
    SysMonApp = win32com.client.Dispatch("System Monitor API")
    if SysMonApp == None:
        print "Pas d'instance System Monitor"
    #endif
    Err = SysMonApp.SetLiveUpdates(True)
    if Err != 0:
        print Err
    #endif
    print "LiveUpdates Actif"
    Err = SysMonApp.MatlabImport(Kit)
    if Err !=0:
        print Err
    #endif
    print "Import kit .m termine"

    SysMonApp = None
    print "Fin du script"    
#endif
========================================================================

Here is an example of a NON-working script:
import os
import win32com.client
from ctypes import *

if __name__ == '__main__':
    print ""
    Kit = "C:\\U\\TNR_MES_2009\\THR2RAT11BA01.m"
    
    SysMonApp = win32com.client.Dispatch("System Monitor API")
    if SysMonApp == None:
        print "Pas d'instance System Monitor"
    #endif

    #OnlineSt = False
    OnlineSt = c_double()
    Err = SysMonApp.GetOnline(byref(OnlineSt))
    if Err != 0:
        print Err
    #endif
    if OnlineSt == True:
        print "ECU Online"
    else:
        print "ECU Offline"
    #endif

    SysMonApp = None
    print "Fin du script"    
#endif

========================================================================
The error message is:

Traceback (most recent call last):
  File "C:\Python26\Lib\site-
packages\pythonwin\pywin\framework\scriptutils.py", line 325, in 
RunScript
    exec codeObject in __main__.__dict__
  File "C:\U\TNR_MES_2009\EssaiSysMonSeul_Output_KO.py", line 16, in 
<module>
    Err = SysMonApp.GetOnline(byref(OnlineSt))
  File "<COMObject System Monitor API>", line 2, in GetOnline
TypeError: Objects of type 'CArgObject' can not be converted to a COM 
VARIANT
========================================================================

As you can see I use the ctype library to try pass output argument, 
using byref.
But I also try to pass argument directly under python, without ctypes:

    OnlineSt = False
    Err = SysMonApp.GetOnline(OnlineSt)

and I had the folowing error message:

Traceback (most recent call last):
  File "C:\Python26\Lib\site-
packages\pythonwin\pywin\framework\scriptutils.py", line 325, in 
RunScript
    exec codeObject in __main__.__dict__
  File "C:\U\TNR_MES_2009\EssaiSysMonSeul_Output_KO.py", line 16, in 
<module>
    Err = SysMonApp.GetOnline(OnlineSt)
  File "<COMObject System Monitor API>", line 2, in GetOnline
com_error: (-2147352571, 'Le type ne correspond pas.', None, 1)
========================================================================

The help for the activeX function explain that the output arguments 
need to be pass as pointer:

GetOnline 
Returns whether the ECU is online or not.
Arguments:
 bool* bResult - whether the ECU is online or offline. 
 



Do you have any idea to solve this problem?

Many thanks

Benjamin

If you need general help, the bug tracker is not the right place where
to ask. If you think you have found a bug please follow these
instructions and explain clearly what the problem is:
http://www.python.org/dev/workflow/.

You might try asking on the ctypes-users mailing list:

https://lists.sourceforge.net/lists/listinfo/ctypes-users

I'll close this for now;  if, after discussing this on the ctypes-users 
list, you're reasonably sure that you've found a bug in Python itself 
(which is what this tracker is for), please come back and open another bug 
report.