Feature or enhancement

The critical section API is useful for making C API extensions thread-safe when the GIL is disabled. Compared to plain mutexes, the API makes it easier to avoid deadlocks, especially when interacting with the Python C API, where calls likePy_DECREF() may invoke destructors that themselves acquire locks.

A more detailed description and motivation is in PEP 703:https://peps.python.org/pep-0703/#python-critical-sections

The underlying implementation is hooked into Python'sPyThreadState management, so it would not be practical to implement this API outside of CPython.

C-API WG Issue

• Make critical section API public as part of non-limited C API capi-workgroup/decisions#26

Linked PRs

• gh-119344: Make critical section API public #119353
• [3.13] gh-119344: Make critical section API public (GH-119353) #120856