But it cannot be compiled outside a function on Windows: https://github.com/python/cpython/actions/runs/7862752441/job/21452578591 with this error:

`3>D:\a\cpython\cpython\Modules\rotatingtree.c(19,16): error C2099: initializer is not a constant [D:\a\cpython\cpython\PCbuild\pythoncore.vcxproj]` 

Also check here be0427f#diff-266bed9d854389a88ddd0696e9a225a2570559901edf0e909de43dd1f49ce80aR19 to see the usage and the compile error.

Change it to PyMutex m = {0}; can resolve this issue.

Linked PRs

• gh-115304: Add doc for initialize PyMutex as global variables #115305