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Re: Defining a Python enum in a C extension - am I doing this right?

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Subject: Re: Defining a Python enum in a C extension - am I doing this right?
Date: Fri, 23 Jul 2021 16:03:03 +0100
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by: MRAB - Fri, 23 Jul 2021 15:03 UTC

On 2021-07-23 09:20, Bartosz Golaszewski wrote:
> Hi!
>
> I'm working on a Python C extension and I would like to expose a
> custom enum (as in: a class inheriting from enum.Enum) that would be
> entirely defined in C.
>
> It turned out to not be a trivial task and the regular mechanism for
> inheritance using .tp_base doesn't work - most likely due to the
> Enum's meta class not being pulled in.
>
> Basically I'm trying to do this:
>
[snip]
>
> static PyObject *make_bases(PyObject *enum_mod)
> {
> PyObject *enum_type, *bases;
>
> enum_type = PyObject_GetAttrString(enum_mod, "Enum");
> if (!enum_type)
> return NULL;
>
> bases = PyTuple_Pack(1, enum_type); /* Steals reference. */

PyTuple_Pack doesn't steal references, as far as I can tell.

> if (!bases)
> Py_DECREF(enum_type);
>
> return bases;
> }
>
[snip]

Subject	Author
Re: Defining a Python enum in a C extension - am I doing this right?	MRAB