The documentation titled "Building C and C++ Extensions on Windows" at http://docs.python.org/py3k/extending/windows.html shows a Python 2.x way of handling static type object initializers, to whit:

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If your module creates a new type, you may have trouble with this line:

PyVarObject_HEAD_INIT(&PyType_Type, 0)

Static type object initializers in extension modules may cause compiles to fail with an error message like “initializer not a constant”. This shows up when building DLL under MSVC. Change it to:

PyVarObject_HEAD_INIT(NULL, 0)

and add the following to the module initialization function:

MyObject_Type.ob_type = &PyType_Type;

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That last line will not function in Python 3.x. However, PyType_Ready will fill in the ob_type field if it is empty, if I understand PyType_Ready correctly. Therefore, the last few lines of this documentation snippet can become:

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and add the following to the module initialization function:

if (PyType_Ready(&MyObject_Type) < 0)
    return NULL;
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