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devel / comp.lang.python / Re: What's the public API alternative to _PyObject_GC_IS_TRACKED()?

Re: What's the public API alternative to _PyObject_GC_IS_TRACKED()?

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From: Marco.Sulla.Python@gmail.com (Marco Sulla)
Newsgroups: comp.lang.python
Subject: Re: What's the public API alternative to _PyObject_GC_IS_TRACKED()?
Date: Tue, 28 Dec 2021 21:17:43 +0100
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by: Marco Sulla - Tue, 28 Dec 2021 20:17 UTC

On Tue, 28 Dec 2021 at 12:38, Inada Naoki <songofacandy@gmail.com> wrote:
> Your case is special.
> You want to create a frozendict which performance is same to builtin dict.
> Builtin dict has special optimization which tightly coupled with
> current CPython implementation.
> So you need to use private APIs for MAINTAIN_TRACKING.

I solved this problem with a hacky trick: I included a reduced and
slightly modified version of dictobject.c. Furthermore I copy / pasted
stringlib\eq.h and _Py_bit_length. I'm currently doing this in a
refactor branch.
(Yes, I know that including a .c is very bad... but I need to do this
to separate the code of dict from the code of frozendict. Putting all
in the same files mess my head)

> But PyObject_GC_Track() is a public API.

The problem is I can't invoke PyObject_GC_Track() on an already
tracked object. I tried it and Python segfaulted. That's why CPython
uses _PyObject_GC_IS_TRACKED() before.

I'll try to copy/paste it too... :D but I do not understand why
there's not a public version of it.

Subject	Author
Re: What's the public API alternative to _PyObject_GC_IS_TRACKED()?	Marco Sulla