[Python-Dev] Status of the Argument Clinic DSL (original) (raw)

eryk sun eryksun at gmail.com
Thu Aug 4 20:27:02 EDT 2016

On Thu, Aug 4, 2016 at 11:33 PM, Alexander Belopolsky <alexander.belopolsky at gmail.com> wrote:

On Thu, Aug 4, 2016 at 7:12 PM, Larry Hastings <larry at hastings.org> wrote:

C extension functions get the module passed in automatically, but this is done internally and from the Python level you can't see it. Always something new to learn! This was not so in Python 2.x - self was passed as NULL to the C module functions. When did this change?

In 2.x this is the self parameter (actually named "passthrough" in the source) of Py_InitModule4 [1, 2]. You probably use the Py_InitModule or Py_InitModule3 macros, which pass NULL for this parameter:

#define Py_InitModule(name, methods) \
    Py_InitModule4(name, methods, (char *)NULL, (PyObject *)NULL, \
               PYTHON_API_VERSION)

#define Py_InitModule3(name, methods, doc) \
    Py_InitModule4(name, methods, doc, (PyObject *)NULL, \
               PYTHON_API_VERSION)

Python 3's PyModule_Create2 [3-5] API makes this a reference to the module. It's currently implemented in PyModule_AddFunctions [6, 7].

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