cpython/Include
Emma Smith f262297d52
gh-139877: Use PyBytesWriter in pycore_blocks_output_buffer.h (#139976)
Previously, the _BlocksOutputBuffer code creates a list of bytes objects to handle the output data from compression libraries. This ends up being slow due to the output buffer code needing to copy each bytes element of the list into the final bytes object buffer at the end of compression.

The new PyBytesWriter API introduced in PEP 782 is an ergonomic and fast method of writing data into a buffer that will later turn into a bytes object. Benchmarks show that using the PyBytesWriter API is 10-30% faster for decompression across a variety of settings. The performance gains are greatest when the decompressor is very performant, such as for Zstandard (and likely zlib-ng). Otherwise the decompressor can bottleneck decompression and the gains are more modest, but still sizable (e.g. 10% faster for zlib)!

Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
2025-10-14 10:03:55 -07:00
..
cpython gh-139640: Fix swallowing syntax warnings in different modules (GH-139755) 2025-10-14 17:48:09 +03:00
internal gh-139877: Use PyBytesWriter in pycore_blocks_output_buffer.h (#139976) 2025-10-14 10:03:55 -07:00
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
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-87347: Add parenthesis around macro arguments (#93915) 2022-06-20 16:04:52 +02:00
descrobject.h gh-103509: PEP 697 -- Limited C API for Extending Opaque Types (GH-103511) 2023-05-04 09:56:53 +02:00
dictobject.h gh-106004: PyDict_GetItemRef() should only be in the limited API 3.13 (GH-107229) 2023-07-25 21:48:07 +03:00
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
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-121040: Use __attribute__((fallthrough)) (#121044) 2024-06-27 09:58:44 +00:00
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-120026: soft deprecate Py_HUGE_VAL macro (#120027) 2024-11-01 22:04:31 +00:00
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-133644: remove deprecated PyImport_ImportModuleNoBlock (#133655) 2025-05-08 13:08:43 +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-132639: Adds PyLong_AsNativeBytes, PyLong_FromNativeBytes and PyLong_FromUnsignedNativeBytes to the limited API (GH-132640) 2025-04-21 15:59:03 +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-137210: Move PYTHON_API_VERSION & PYTHON_ABI_VERSION to patchlevel.h (GH-138545) 2025-09-08 12:02:13 +02:00
moduleobject.h gh-137210: Add a struct, slot & function for checking an extension's ABI (GH-137212) 2025-09-05 16:23:18 +02:00
object.h gh-137956: Guard against non-free-threaded extensions in free-threaded builds (GH-137957) 2025-09-15 11:24:16 +00:00
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-134282: Always borrow references LOAD_CONST (GH-134284) 2025-05-20 11:24:11 -04:00
osdefs.h gh-108765: Reformat Include/osdefs.h (#108766) 2023-09-01 14:35:39 +00:00
osmodule.h
patchlevel.h Post 3.15.0a1 2025-10-14 17:36:01 +03:00
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
pydtrace.h Fix pydtrace.d path comment in Include/pydtrace.h (#28539) 2022-12-31 22:40:25 +05:30
pyerrors.h gh-119521: Rename IncompleteInputError to _IncompleteInputError and remove from public API/ABI (GH-119680) 2024-06-24 14:08:12 +02:00
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-138143: Allow anonymous unions in public headers, using _Py_ANONYMOUS (GH-137283) 2025-08-26 11:14:35 +02:00
pymath.h gh-136006: fix Py_NAN expansion on Solaris systems (#136575) 2025-09-10 11:11:04 +02:00
pymem.h gh-85283: Add PyMem_RawMalloc() to the limited C API (#108570) 2023-10-17 02:41:51 +02:00
pyport.h gh-137058: Update C23 standard version check in pyport.h (#137127) 2025-07-27 09:47:21 +02:00
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
pystrtod.h gh-106320: Remove private float C API functions (#108430) 2023-08-24 19:09:49 +02:00
Python.h gh-79315: Remove Include/pylock.h and Include/monitoring.h (#139731) 2025-10-08 00:49:24 +02:00
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-111506: Add _Py_OPAQUE_PYOBJECT to hide PyObject layout & related API (GH-136505) 2025-07-12 09:55:12 +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/