ctypes, error when calling function

[Max M]

Trying to write realtime midi in Windows I am using ctypes. So I have 
written a small wrapper for winmm.dll

It partly works. I get this error when I try to run it:

Traceback (most recent call last):
   File "E:\maxm\pys\MIDI-R~1\x.py", line 203, in ?
     print winmm.midiOutGetDevCaps(deviceID, caps, sizeof(caps))
   File "E:\maxm\pys\MIDI-R~1\x.py", line 133, in __getattr__
     return getattr(self._winmm, attr)
   File "C:\pytyons\Python23\Lib\site-packages\ctypes\__init__.py", line 
316, in __getattr__
     func = self._StdcallFuncPtr(name, self)
AttributeError: function 'midiOutGetDevCaps' not found

But the documentation says that the midiOutGetDevCaps() should exist in 
the dll.

It calls the midiOutGetNumDevs() function in the dll nicely, wich is why 
I find it to be strange problem.

Does anybody have a clue? It's my first try at ctypes, so I am a bit 
lost here.

regards Max M


#################################3
# The code

from ctypes import *

MAXPNAMELEN = 32

class MIDIOUTCAPS(Structure):
     _fields_ = [
         ("wMid", c_int), # WORD
         ("wPid", c_int), # WORD
         ("vDriverVersion", c_long), # MMVERSION
         ("szPname", c_char * MAXPNAMELEN), # CHAR
         ("wTechnology", c_int), # WORD
         ("wVoices", c_int), # WORD
         ("wNotes", c_int), # WORD
         ("wChannelMask", c_int), # WORD
         ("dwSupport", c_long), # DWORD
     ]


class Winmm:

     """A *very* thin wrapper over WINMM.DLL :-)
     """

     def __init__(self):
         self._winmm = windll.WINMM

     def __getattr__(self, attr):
         return getattr(self._winmm, attr)



if __name__ == '__main__':

     caps = MIDIOUTCAPS()
     winmm = Winmm()
     numDevs = winmm.midiOutGetNumDevs()
     for deviceID in range(-1, numDevs):
         print winmm.midiOutGetDevCaps(deviceID, caps, sizeof(caps))






-- 

hilsen/regards Max M, Denmark

http://www.mxm.dk/
IT's Mad Science