Problems with nested structures

Hello, 

I have a problem getting nested structures from a C-API interface.
The call succeeds but all members in the nested elements are empty.

Could my definition of the call be wrong or is there any restriction in
C-Types that 
structures with structures with union are not transported ? 

I'm working with ctypes 0.6.3 and Python 2.2.1.

        Thanks 

                Stefan



Background:

The call I want to wrap is defined as

int GetData( unsigned char** pRecvBuffer, unsigned short* pObjNum); 

where the first element is a Structure with nested structures in C, e.g.
sample C-Code

  unsigned char*     RecvBuffer;
  WORD               nObj;
  MyStruct*        Data;
  iRet = GetData(&RecvBuffer, &nObj);

  if (iRet &&  nObj>0)
  {
      Data = (MyStruct*)(RecvBuffer); 

where the structure is defined as:

typedef struct {
  unsigned char        Length;
  LogStruct            Log;
} MyStruct;

with:

typedef struct {
  unsigned char     Length;
  unsigned char     Data[8];
  IDUnion                 ID;
} LogStruct;

with:

typedef union
{
  unsigned long Dword;
  unsigned short Word[2];
  unsigned char Byte[4];
} IDUnion;


and I wrapped it with:

class MyStruct(ctypes.Structure):
    _fields_ = [
                ("Length", ctypes.c_ubyte),
                ("Log", LogStruct),
                ]


class LogStruct(ctypes.Structure):
    _fields_ = [("Length", ctypes.c_ubyte),
                ("Data", ctypes.c_ubyte * 8),
                ("ID",   IDUnion ),
                ] 

class IDUnion(ctypes.Union):
    _fields_ = [("Dword", ctypes.c_ulong),
                ("Word", ctypes.c_ushort * 2),
                ("Byte", ctypes.c_ubyte * 4)
                ]

def GetData(self):
    LocalpRecvBuffer = ctypes.pointer(MyStruct())
    LocalpObjNum = ctypes.c_ushort()
    self._Handle.GetData(ctypes.byref(LocalpRecvBuffer),
ctypes.byref(LocalpObjNum))
    if LocalpObjNum.value > 0:
       return LocalpRecvBuffer.contents, LocalpObjNum.value
    else:
       return None, 0 

All elements of Logstruct and IDUnion aree still empty after the call.


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