Hi all,
I've had cause to instantiate a COM class which is not registered on the
system. To do this, one uses DllGetClassObject on the dll and then calls
CreateInstance on the resulting IClassFactory.
IClassFactory::CreateInstance is defined as:
HRESULT CreateInstance(
[in] IUnknown *pUnkOuter,
[in] REFIID riid,
[out] void **ppvObject
);
However, in comtypes.server.IClassFactory, CreateInstance is defined as
follows:
_methods_ = [
comtypes.STDMETHOD(comtypes.HRESULT, "CreateInstance",
[ctypes.c_int,
ctypes.POINTER(comtypes.GUID), ctypes.POINTER(ctypes.c_ulong)]),
...
The final parameter being declared as c_ulong makes life a little
painful. In order to use it, you have to do something like:
instance = ctypes.c_ulong()
factory.CreateInstance(0, interface._iid_, ctypes.byref(instance))
instance = ctypes.POINTER(interface)(instance.value)
First of all, is there a reason that last parameter is c_ulong instead
of c_void_p or the like?
Second, is there any chance we could make this more Pythonic like the
recent IServiceProvider.QueryInterface? Something like:
instance = factory.CreateInstance(interface=interface)
I'm curious as to how frequently this is already used, as such a change
would break existing usage.
Jamie
--
James Teh
Email/MSN Messenger/Jabber: [email protected]
Web site: http://www.jantrid.net/
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