`sysconfig.get_config_var("Py_DEBUG")` is not picked up on Windows builds

[cctv130]

I used the PCbuild\build.bat -e -d -p x64 command to build, but when I print PY_DEBUG, it returns None.

[StanFromIreland]

Help questions belong in the python discourse.

[picnixz]

@zooba should a build with -d be expected to define Py_DEBUG as well? We have this

/* _DEBUG implies Py_DEBUG */
#ifdef _DEBUG
#  define Py_DEBUG 1
#endif

but it appears that sysconfig can't pick this up.

[picnixz]

@cctv130 Does it work better if you're using Python 3.13 or Python 3.14?

[StanFromIreland]

It should, as per the docs:

cpython/PCbuild/readme.txt

Lines 35 to 42 in 9b9cdb6

	Debug
	Used to build Python with extra debugging capabilities, equivalent
	to using ./configure --with-pydebug on UNIX. All binaries built
	using this configuration have "_d" added to their name:
	python310_d.dll, python_d.exe, parser_d.pyd, and so on. Both the
	build and rt (run test) batch files in this directory accept a -d
	option for debug builds. If you are building Python to help with
	development of CPython, you will most likely use this configuration.

[cctv130]

@StanFromIreland
On the Windows platform, the compilation method is different from Linux; the ./configure command is not supported on Windows.

[cctv130]

@zooba should a build with -d be expected to define Py_DEBUG as well? We have this

/* _DEBUG implies Py_DEBUG */
#ifdef _DEBUG
#  define Py_DEBUG 1
#endif

but it appears that sysconfig can't pick this up.

If that's the case, then the _DEBUG flag must be added to the MSVC compiler.

[picnixz]

_DEBUG is already MSVC-specific; I think it's more a sysconfig issue

[cctv130]

@picnixz
If that's the case, we can use CMake configuration instead of configure to support more platforms.