Unable to compile my C Extension on Windows: unresolved external link errors

[Chris Angelico]

On Sat, Nov 13, 2021 at 3:28 AM Marco Sulla
<Marco.Sulla.Python at gmail.com> wrote:
>
> On Fri, 12 Nov 2021 at 15:55, Gisle Vanem <gisle.vanem at gmail.com> wrote:
> > Marco Sulla wrote:
> > > Error LNK2001: unresolved external symbol PyErr_SetObject
> > >
> > > and so on.
> > >
> > > I post the part of my setup.py about the C Extension:
> > >
> > > extra_compile_args = ["-DPY_SSIZE_T_CLEAN", "-DPy_BUILD_CORE"]
> >
> > Shouldn't this be "-DPy_BUILD_CORE_MODULE"?
>
> I tried it, but now I get three
>
> error C2099: initializer is not a constant
>
> when I try to compile dictobject.c. Yes, my extension needs dictobject.

Are you sure that you really need Py_BUILD_CORE? Here's what the code
has to say about it:

https://github.com/python/cpython/blob/main/Include/pyport.h#L17

Py_BUILD_CORE: Build Python core. Give access to Python internals, but
should not be used by third-party modules.

If your extension truly needs to reach into the internals of CPython,
then you're going to have to figure a lot of things out for yourself,
including how to make sure it works on every platform. A more
productive approach would be to stick to the actual API:

https://docs.python.org/3/c-api/stable.html

What is it that doesn't work without Py_BUILD_CORE?

ChrisA