cpython/Include
Sam Gross 6577d870b0
gh-144438: Fix false sharing between QSBR and tlbc_index (gh-144554)
Align the QSBR thread state array to a 64-byte cache line boundary
and add padding at the end of _PyThreadStateImpl. Depending on heap
layout, the QSBR array could end up sharing a cache line with a
thread's tlbc_index, causing QSBR quiescent state updates to contend
with reads of tlbc_index in RESUME_CHECK. This is sensitive to
earlier allocations during interpreter init and can appear or
disappear with seemingly unrelated changes.

Either change alone is sufficient to fix the specific issue, but both
are worthwhile to avoid similar problems in the future.
2026-02-17 11:12:25 -05:00
..
cpython gh-141510, PEP 814: Add built-in frozendict type (#144757) 2026-02-17 10:54:41 +01:00
internal gh-144438: Fix false sharing between QSBR and tlbc_index (gh-144554) 2026-02-17 11:12:25 -05:00
abstract.h gh-134989: Implement PyObject_DelAttr() as a macro in the limited C API (GH-135021) 2025-06-04 15:07:52 +02:00
audit.h gh-135755: Use private names (_Py*) for header file guards new in 3.14 (GH-135921) 2025-06-26 13:05:01 +02:00
bltinmodule.h these builtins have to be initialized 2009-05-09 18:10:51 +00:00
boolobject.h gh-134989: Fix Py_RETURN_NONE in the limited C API (GH-135165) 2025-06-05 14:43:47 +02:00
bytearrayobject.h gh-87347: Add parenthesis around PyXXX_Check() arguments (#92815) 2022-06-16 13:49:43 +02:00
bytesobject.h gh-108765: Move standard includes to Python.h (#108769) 2023-09-01 21:03:20 +02:00
ceval.h gh-135755: Move SPECIAL_ constants to a private header (GH-135922) 2025-06-25 13:03:05 +02:00
codecs.h Remove private _PyCodec_Lookup() function (#106269) 2023-06-30 09:34:01 +00:00
compile.h gh-109596: Ensure repeated rules in the grammar are not allowed and fix incorrect soft keywords (#109606) 2023-09-22 19:03:23 +01:00
complexobject.h gh-87347: Add parenthesis around PyXXX_Check() arguments (#92815) 2022-06-16 13:49:43 +02:00
critical_section.h gh-119344: Make critical section API public (#119353) 2024-06-21 15:50:18 -04:00
datetime.h gh-141563: Add missing cast to _PyDateTime_IMPORT() (#144667) 2026-02-10 14:47:12 +00:00
descrobject.h gh-41779: Allow defining any __slots__ for a class derived from tuple (GH-141763) 2026-01-06 11:36:00 +02:00
dictobject.h gh-141726: Add PyDict_SetDefaultRef() to the Stable ABI (#141727) 2025-11-19 11:38:10 +00:00
dynamic_annotations.h gh-96959: Update HTTP links which are redirected to HTTPS (GH-96961) 2022-09-24 14:38:53 +03:00
enumobject.h Implement and apply PEP 322, reverse iteration 2003-11-06 14:06:48 +00:00
errcode.h gh-107450: Check for overflow in the tokenizer and fix overflow test (#110832) 2023-10-16 16:42:49 +02:00
exports.h gh-141671: PyMODINIT_FUNC: apply __declspec(dllexport) on Windows (GH-141672) 2026-01-07 13:09:48 +01:00
fileobject.h gh-106320: Remove _PyIsSelectable_fd() C API (#107142) 2023-07-23 19:07:12 +00:00
fileutils.h gh-67341: fix a typo in Include/fileutils.h (#136049) 2025-07-14 08:02:05 +00:00
floatobject.h gh-141004: soft-deprecate Py_INFINITY macro (#141033) 2025-11-12 13:44:49 +01:00
frameobject.h bpo-45434: Remove useless space in includes (GH-28963) 2021-10-15 01:50:04 +02:00
genericaliasobject.h bpo-44654: Refactor and clean up the union type implementation (GH-27196) 2021-07-17 22:44:10 +03:00
import.h gh-142349: Fix build errors from PEP 810 (#144726) 2026-02-12 08:18:36 +00:00
intrcheck.h gh-106320: Remove private _PyOS_IsMainThread() function (#108605) 2023-08-29 03:20:31 +00:00
iterobject.h gh-106320: Remove _PyAnextAwaitable_Type from the public C API (#108597) 2023-08-29 02:05:11 +00:00
listobject.h gh-114329: Fix PyList_GetItemRef() limited C API definition (#117520) 2024-04-03 21:02:42 +00:00
longobject.h gh-143869: Add PEP 757 functions to the limited API (#143906) 2026-01-21 14:47:14 +01:00
marshal.h gh-79315: Add Include/cpython/marshal.h header (#139725) 2025-10-07 23:49:08 +02:00
memoryobject.h gh-79315: Add Include/cpython/memoryobject.h header (#99723) 2022-11-23 15:44:42 +01:00
methodobject.h gh-132097: use a macro for semantically casting function pointers (#132406) 2025-04-18 12:24:34 +02:00
modsupport.h gh-142225: Fix PyABIInfo_VAR macro (GH-142230) 2025-12-04 10:33:15 +01:00
moduleobject.h gh-143883: Use named parameters in PyModExport-related declarations & docs (GH-143884) 2026-01-27 10:28:28 +00:00
object.h gh-139165: Make Py_SIZE, Py_IS_TYPE,Py_ SET_SIZE regular functions in stable ABI (GH-139166) 2025-11-25 14:30:33 +01:00
objimpl.h gh-102013: Move PyUnstable_GC_VisitObjects() to Include/cpython/objimpl.h (#115560) 2024-02-16 15:49:13 +01:00
opcode.h gh-100239: replace BINARY_SUBSCR & family by BINARY_OP with oparg NB_SUBSCR (#129700) 2025-02-07 22:39:54 +00:00
opcode_ids.h gh-142982: Specialize CALL_FUNCTION_EX (GH-143391) 2026-01-06 20:34:08 +00:00
osdefs.h gh-108765: Reformat Include/osdefs.h (#108766) 2023-09-01 14:35:39 +00:00
osmodule.h Issue #29058: All stable API extensions added after Python 3.2 are now 2016-12-27 14:57:39 +02:00
patchlevel.h Post 3.15.0a6 2026-02-11 17:33:36 +02:00
py_curses.h gh-125843: indicate which C function caused a curses.error (#125844) 2025-05-19 15:53:39 +02:00
pyatomic.h gh-108724: Add PyMutex and _PyParkingLot APIs (gh-109344) 2023-09-19 09:54:29 -06:00
pybuffer.h gh-102500: Implement PEP 688 (#102521) 2023-05-04 07:59:46 -07:00
pycapsule.h gh-108240: Add pycore_capsule.h internal header file (#108596) 2023-08-29 01:20:02 +00:00
pydtrace.d bpo-36842: Implement PEP 578 (GH-12613) 2019-05-23 08:45:22 -07:00
pydtrace.h Fix pydtrace.d path comment in Include/pydtrace.h (#28539) 2022-12-31 22:40:25 +05:30
pyerrors.h gh-142349: Implement PEP 810 - Explicit lazy imports (#142351) 2026-02-12 00:15:33 +00:00
pyexpat.h gh-90949: expose Expat API to tune exponential expansion protections (#139368) 2025-09-28 08:27:04 +00:00
pyframe.h gh-93937, C API: Move PyFrame_GetBack() to Python.h (#93938) 2022-06-19 12:02:33 +02:00
pyhash.h gh-111545: Add Include/cpython/pyhash.h header file (#112063) 2023-11-15 01:19:20 +01:00
pylifecycle.h gh-133644: Remove deprecated Python initialization getter functions (#133661) 2025-05-09 11:39:23 +00:00
pymacconfig.h gh-110820: Make sure processor specific defines are correct for Universal 2 build on macOS (#112828) 2023-12-08 10:09:34 +01:00
pymacro.h gh-141370: Fix undefined behavior when using Py_ABS() (GH-141548) 2025-12-05 16:24:35 +02:00
pymath.h gh-141004: soft-deprecate Py_INFINITY macro (#141033) 2025-11-12 13:44:49 +01:00
pymem.h gh-85283: Add PyMem_RawMalloc() to the limited C API (#108570) 2023-10-17 02:41:51 +02:00
pyport.h gh-121617: Include <string.h> for Py_CLEAR() macro (#144666) 2026-02-12 17:03:55 +01:00
pystate.h gh-108867: Add PyThreadState_GetUnchecked() function (#108870) 2023-10-03 16:53:51 +00:00
pystats.h GH-124284: Add stats for refcount operations on immortal objects (GH-124288) 2024-09-23 19:10:55 +01:00
pystrcmp.h Merged revisions 59541-59561 via svnmerge from 2007-12-19 02:07:34 +00:00
pystrtod.h gh-106320: Remove private float C API functions (#108430) 2023-08-24 19:09:49 +02:00
Python.h gh-121617: Include <string.h> for Py_CLEAR() macro (#144666) 2026-02-12 17:03:55 +01:00
pythonrun.h gh-130396: Move PYOS_LOG2_STACK_MARGIN to internal headers (#135928) 2025-07-01 15:18:17 +02:00
pythread.h gh-137884: Added threading.get_native_id() on Illumos/Solaris (GH-137927) 2025-08-20 17:10:44 +00:00
pytypedefs.h bpo-45459: Fix PyModuleDef_Slot type in the limited C API (GH-31668) 2022-03-03 23:06:55 +01:00
rangeobject.h gh-87347: Add parenthesis around PyXXX_Check() arguments (#92815) 2022-06-16 13:49:43 +02:00
README.rst gh-101101: Unstable C API tier (PEP 689) (GH-101102) 2023-02-28 09:31:01 +01:00
refcount.h gh-140153: Fix Py_REFCNT() definition on limited C API 3.11-3.13 (#140158) 2025-10-15 16:36:49 +02:00
setobject.h gh-87347: Add parenthesis around PyXXX_Check() arguments (#92815) 2022-06-16 13:49:43 +02:00
sliceobject.h gh-79315: Add Include/cpython/sliceobject.h header (#139729) 2025-10-08 00:48:18 +02:00
structmember.h Fix typos in comments (#120188) 2024-06-07 10:19:41 +02:00
structseq.h gh-79315: Add Include/cpython/structseq.h header (#139730) 2025-10-08 01:19:50 +02:00
sysmodule.h gh-138886: Remove deprecated PySys_ResetWarnOptions C-API function (#138887) 2025-09-15 12:01:33 +03:00
traceback.h gh-87347: Add parenthesis around PyXXX_Check() arguments (#92815) 2022-06-16 13:49:43 +02:00
tupleobject.h gh-87347: Add parenthesis around PyXXX_Check() arguments (#92815) 2022-06-16 13:49:43 +02:00
typeslots.h Revert "gh-133395: add option for extension modules to specialize BINARY_OP/SUBSCR, apply to arrays (#133396)" (#133498) 2025-05-06 13:12:26 +03:00
unicodeobject.h gh-133610: Remove PyUnicode_AsDecoded/Encoded functions (#133612) 2025-05-09 17:31:24 +02:00
warnings.h bpo-35134: Split warnings.h and weakrefobject.h (GH-29042) 2021-10-19 01:31:57 +02:00
weakrefobject.h gh-133644: remove PyWeakref_GetObject and PyWeakref_GET_OBJECT (GH-133657) 2025-09-24 11:25:56 +02:00

The Python C API
================

The C API is divided into these sections:

1. ``Include/``: Limited API
2. ``Include/cpython/``: CPython implementation details
3. ``Include/cpython/``, names with the ``PyUnstable_`` prefix: API that can
   change between minor releases
4. ``Include/internal/``, and any name with ``_`` prefix: The internal API

Information on changing the C API is available `in the developer guide`_

.. _in the developer guide: https://devguide.python.org/c-api/