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Merge remote-tracking branch 'origin/main' into pairwise_ft_v3

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# Conflicts:
#	Lib/test/test_free_threading/test_itertools.py
#	Modules/itertoolsmodule.c
This commit is contained in:
Pieter Eendebak 2026-04-27 21:46:41 +02:00
commit 78eabbc87d
1639 changed files with 109108 additions and 43404 deletions
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4
.gitattributes vendored
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@ -34,6 +34,9 @@ Lib/test/xmltestdata/* noeol
Lib/venv/scripts/common/activate text eol=lf
Lib/venv/scripts/posix/* text eol=lf
# Prevent GitHub's web conflict editor from converting LF to CRLF
*.rst text eol=lf
# CRLF files
[attr]dos text eol=crlf
@ -112,3 +115,4 @@ Tools/peg_generator/pegen/grammar_parser.py generated
aclocal.m4 generated
configure generated
*.min.js generated
package-lock.json generated

98
.github/CODEOWNERS vendored
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@ -63,9 +63,10 @@
.azure-pipelines/ @AA-Turner
# GitHub & related scripts
.github/ @ezio-melotti @hugovk @AA-Turner @webknjaz
Tools/build/compute-changes.py @AA-Turner @hugovk @webknjaz
Tools/build/verify_ensurepip_wheels.py @AA-Turner @pfmoore @pradyunsg
.github/ @ezio-melotti @hugovk @AA-Turner @webknjaz
Tools/build/compute-changes.py @AA-Turner @hugovk @webknjaz
Lib/test/test_tools/test_compute_changes.py @AA-Turner @hugovk @webknjaz
Tools/build/verify_ensurepip_wheels.py @AA-Turner @pfmoore @pradyunsg
# Pre-commit
.pre-commit-config.yaml @hugovk
@ -99,17 +100,18 @@ Lib/test/test_build_details.py @FFY00
InternalDocs/ @AA-Turner
# Tools, Configuration, etc
Doc/Makefile @AA-Turner @hugovk
Doc/_static/ @AA-Turner @hugovk
Doc/conf.py @AA-Turner @hugovk
Doc/make.bat @AA-Turner @hugovk
Doc/requirements.txt @AA-Turner @hugovk
Doc/tools/ @AA-Turner @hugovk
Doc/Makefile @AA-Turner @hugovk @StanFromIreland
Doc/_static/ @AA-Turner @hugovk @StanFromIreland
Doc/conf.py @AA-Turner @hugovk @StanFromIreland
Doc/make.bat @AA-Turner @hugovk @StanFromIreland
Doc/requirements.txt @AA-Turner @hugovk @StanFromIreland
Doc/tools/ @AA-Turner @hugovk @StanFromIreland
# PR Previews
.readthedocs.yml @AA-Turner
# Sections
Doc/c-api/ @ZeroIntensity
Doc/reference/ @willingc @AA-Turner
Doc/whatsnew/ @AA-Turner
@ -130,7 +132,9 @@ Tools/c-analyzer/ @ericsnowcurrently
Tools/check-c-api-docs/ @ZeroIntensity
# Fuzzing
Modules/_xxtestfuzz/ @ammaraskar
Modules/_xxtestfuzz/ @python/fuzzers
Lib/test/test_xxtestfuzz.py @python/fuzzers
.github/workflows/reusable-cifuzz.yml @python/fuzzers
# Limited C API & Stable ABI
Doc/c-api/stable.rst @encukou
@ -258,40 +262,46 @@ Include/pyhash.h @gpshead @picnixz
Python/pyhash.c @gpshead @picnixz
# The import system (including importlib)
**/*import* @brettcannon @ericsnowcurrently @ncoghlan @warsaw
Python/import.c @brettcannon @ericsnowcurrently @ncoghlan @warsaw @kumaraditya303
**/*import* @brettcannon @ericsnowcurrently @ncoghlan @warsaw @FFY00
Python/import.c @brettcannon @ericsnowcurrently @ncoghlan @warsaw @FFY00 @kumaraditya303
**/*freeze* @ericsnowcurrently
**/*frozen* @ericsnowcurrently
**/*modsupport* @ericsnowcurrently
**/*modulefinder* @ericsnowcurrently
**/*modulefinder* @ericsnowcurrently @FFY00
**/*moduleobject* @ericsnowcurrently
**/*multiphase* @ericsnowcurrently
**/*pkgutil* @ericsnowcurrently
**/*pkgutil* @ericsnowcurrently @FFY00
**/*pythonrun* @ericsnowcurrently
**/*runpy* @ericsnowcurrently
**/*runpy* @ericsnowcurrently @FFY00
**/*singlephase* @ericsnowcurrently
Doc/c-api/module.rst @ericsnowcurrently
Lib/test/test_module/ @ericsnowcurrently
Python/dynload_*.c @ericsnowcurrently
Python/dynload_*.c @ericsnowcurrently @FFY00
# Initialisation
**/*initconfig* @ericsnowcurrently
**/*pathconfig* @ericsnowcurrently
**/*preconfig* @ericsnowcurrently
**/*initconfig* @ericsnowcurrently @FFY00
**/*pathconfig* @ericsnowcurrently @FFY00
**/*preconfig* @ericsnowcurrently @FFY00
Doc/library/sys_path_init.rst @FFY00
Doc/c-api/init_config.rst @FFY00
# Interpreter main program
Modules/main.c @ericsnowcurrently
Programs/_bootstrap_python.c @ericsnowcurrently
Programs/python.c @ericsnowcurrently
Modules/main.c @ericsnowcurrently @FFY00
Programs/_bootstrap_python.c @ericsnowcurrently @FFY00
Programs/python.c @ericsnowcurrently @FFY00
# JIT
.github/workflows/jit.yml @savannahostrowski
Include/internal/pycore_jit.h @brandtbucher @savannahostrowski @diegorusso
Python/jit.c @brandtbucher @savannahostrowski @diegorusso
Tools/jit/ @brandtbucher @savannahostrowski @diegorusso
InternalDocs/jit.md @brandtbucher @savannahostrowski @diegorusso @AA-Turner
# Lazy imports (PEP 810)
Objects/lazyimportobject.c @yhg1s @DinoV @pablogsal
Include/internal/pycore_lazyimportobject.h @yhg1s @DinoV @pablogsal
Lib/test/test_lazy_import @yhg1s @DinoV @pablogsal
# Micro-op / μop / Tier 2 Optimiser
Python/optimizer.c @markshannon @Fidget-Spinner
Python/optimizer_analysis.c @markshannon @tomasr8 @Fidget-Spinner @savannahostrowski
@ -308,8 +318,8 @@ Tools/peg_generator/ @pablogsal @lysnikolaou
# Runtime state/lifecycle
**/*gil* @ericsnowcurrently
**/*pylifecycle* @ericsnowcurrently @ZeroIntensity
**/*pystate* @ericsnowcurrently @ZeroIntensity
**/*pylifecycle* @ericsnowcurrently @ZeroIntensity @FFY00
**/*pystate* @ericsnowcurrently @ZeroIntensity @FFY00
Include/internal/pycore_*_init.h @ericsnowcurrently
Include/internal/pycore_*_state.h @ericsnowcurrently
Include/internal/pycore_atexit.h @ericsnowcurrently
@ -417,18 +427,19 @@ Lib/dataclasses.py @ericvsmith
Lib/test/test_dataclasses/ @ericvsmith
# Dates and times
Doc/**/*time.rst @pganssle @abalkin
Doc/library/zoneinfo.rst @pganssle
Include/datetime.h @pganssle @abalkin
Include/internal/pycore_time.h @pganssle @abalkin
Lib/test/test_zoneinfo/ @pganssle
Lib/zoneinfo/ @pganssle
Lib/*time.py @pganssle @abalkin
Lib/test/datetimetester.py @pganssle @abalkin
Lib/test/test_*time.py @pganssle @abalkin
Modules/*zoneinfo* @pganssle
Modules/*time* @pganssle @abalkin
Python/pytime.c @pganssle @abalkin
Doc/**/*time.rst @pganssle @StanFromIreland
Doc/library/datetime-* @pganssle @StanFromIreland
Doc/library/zoneinfo.rst @pganssle @StanFromIreland
Include/datetime.h @pganssle @StanFromIreland
Include/internal/pycore_time.h @pganssle @StanFromIreland
Lib/test/test_zoneinfo/ @pganssle @StanFromIreland
Lib/zoneinfo/ @pganssle @StanFromIreland
Lib/*time.py @pganssle @StanFromIreland
Lib/test/datetimetester.py @pganssle @StanFromIreland
Lib/test/test_*time.py @pganssle @StanFromIreland
Modules/*zoneinfo* @pganssle @StanFromIreland
Modules/*time* @pganssle @StanFromIreland
Python/pytime.c @pganssle @StanFromIreland
# Dbm
Doc/library/dbm.rst @corona10 @erlend-aasland @serhiy-storchaka
@ -467,8 +478,9 @@ Lib/test/test_functools.py @rhettinger
Modules/_functoolsmodule.c @rhettinger
# Garbage collector
Modules/gcmodule.c @pablogsal
Doc/library/gc.rst @pablogsal
Modules/gcmodule.c @pablogsal
Doc/library/gc.rst @pablogsal
InternalDocs/garbage_collector.md @pablogsal
# Gettext
Doc/library/gettext.rst @tomasr8
@ -495,13 +507,13 @@ Lib/idlelib/ @terryjreedy
Lib/turtledemo/ @terryjreedy
# importlib.metadata
Doc/library/importlib.metadata.rst @jaraco @warsaw
Lib/importlib/metadata/ @jaraco @warsaw
Lib/test/test_importlib/metadata/ @jaraco @warsaw
Doc/library/importlib.metadata.rst @jaraco @warsaw @FFY00
Lib/importlib/metadata/ @jaraco @warsaw @FFY00
Lib/test/test_importlib/metadata/ @jaraco @warsaw @FFY00
# importlib.resources
Doc/library/importlib.resources.abc.rst @jaraco @warsaw
Doc/library/importlib.resources.rst @jaraco @warsaw
Doc/library/importlib.resources.abc.rst @jaraco @warsaw @FFY00
Doc/library/importlib.resources.rst @jaraco @warsaw @FFY00
Lib/importlib/resources/ @jaraco @warsaw @FFY00
Lib/test/test_importlib/resources/ @jaraco @warsaw @FFY00

3
.github/ISSUE_TEMPLATE/documentation.yml vendored
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@ -8,8 +8,9 @@ body:
> [!NOTE]
> Trivial changes (for example typos) don’t require an issue before opening a PR.
- type: textarea
id: description
attributes:
label: "Documentation"
description: "A clear and concise description of the issue."
description: "A clear and concise description of the issue. Include a link to the page."
validations:
required: true

5
.github/actionlint.yaml vendored
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@ -1,8 +1,3 @@
self-hosted-runner:
# Pending https://github.com/rhysd/actionlint/issues/533
# and https://github.com/rhysd/actionlint/issues/571
labels: ["windows-11-arm", "macos-15-intel"]
config-variables: null
paths:

8
.github/dependabot.yml vendored
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@ -3,7 +3,7 @@ updates:
- package-ecosystem: "github-actions"
directory: "/"
schedule:
interval: "monthly"
interval: "quarterly"
labels:
- "skip issue"
- "skip news"
@ -12,6 +12,10 @@ updates:
update-types:
- "version-update:semver-minor"
- "version-update:semver-patch"
groups:
actions:
patterns:
- "*"
cooldown:
# https://blog.yossarian.net/2025/11/21/We-should-all-be-using-dependency-cooldowns
# Cooldowns protect against supply chain attacks by avoiding the
@ -20,7 +24,7 @@ updates:
- package-ecosystem: "pip"
directory: "/Tools/"
schedule:
interval: "monthly"
interval: "quarterly"
labels:
- "skip issue"
- "skip news"

4
.github/workflows/add-issue-header.yml vendored
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@ -12,6 +12,8 @@ on:
# Only ever run once
- opened
permissions:
contents: read
jobs:
add-header:
@ -20,7 +22,7 @@ jobs:
issues: write
timeout-minutes: 5
steps:
- uses: actions/github-script@v8
- uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8.0.0
with:
# language=JavaScript
script: |

201
.github/workflows/build.yml vendored
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@ -64,7 +64,7 @@ jobs:
run: |
apt update && apt install git -yq
git config --global --add safe.directory "$GITHUB_WORKSPACE"
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
fetch-depth: 1
persist-credentials: false
@ -101,18 +101,16 @@ jobs:
needs: build-context
if: needs.build-context.outputs.run-tests == 'true'
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- uses: actions/setup-python@v6
- uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
with:
python-version: '3.x'
- name: Runner image version
run: echo "IMAGE_OS_VERSION=${ImageOS}-${ImageVersion}" >> "$GITHUB_ENV"
- name: Install dependencies
run: sudo ./.github/workflows/posix-deps-apt.sh
- name: Add ccache to PATH
run: echo "PATH=/usr/lib/ccache:$PATH" >> "$GITHUB_ENV"
- name: Configure CPython
run: |
# Build Python with the libpython dynamic library
@ -167,13 +165,21 @@ jobs:
free-threading:
- false
- true
interpreter:
- switch-case
exclude:
# Skip Win32 on free-threaded builds
- { arch: Win32, free-threading: true }
include:
# msvc::musttail is currently only supported on x64,
# and only supported on 3.15+.
- { arch: x64, free-threading: false, interpreter: tail-call }
- { arch: x64, free-threading: true, interpreter: tail-call }
uses: ./.github/workflows/reusable-windows.yml
with:
arch: ${{ matrix.arch }}
free-threading: ${{ matrix.free-threading }}
interpreter: ${{ matrix.interpreter }}
build-windows-msi:
# ${{ '' } is a hack to nest jobs under the same sidebar category.
@ -200,10 +206,10 @@ jobs:
strategy:
fail-fast: false
matrix:
# macos-14 is M1, macos-15-intel is Intel.
# macos-26 is Apple Silicon, macos-15-intel is Intel.
# macos-15-intel only runs tests against the GIL-enabled CPython.
os:
- macos-14
- macos-26
- macos-15-intel
free-threading:
- false
@ -242,14 +248,21 @@ jobs:
# BOLT currently crashes during instrumentation on aarch64
- os: ubuntu-24.04-arm
bolt: true
include:
# Enable CPU-intensive tests on ARM (default build only)
- os: ubuntu-24.04-arm
bolt: false
free-threading: false
test-opts: '-u cpu'
uses: ./.github/workflows/reusable-ubuntu.yml
with:
bolt-optimizations: ${{ matrix.bolt }}
free-threading: ${{ matrix.free-threading }}
os: ${{ matrix.os }}
test-opts: ${{ matrix.test-opts || '' }}
build-ubuntu-ssltests-openssl:
name: 'Ubuntu SSL tests with OpenSSL'
build-ubuntu-ssltests:
name: 'Ubuntu SSL tests'
runs-on: ${{ matrix.os }}
timeout-minutes: 60
needs: build-context
@ -258,18 +271,27 @@ jobs:
fail-fast: false
matrix:
os: [ubuntu-24.04]
# Keep 1.1.1w in our list despite it being upstream EOL and otherwise
# unsupported as it most resembles other 1.1.1-work-a-like ssl APIs
# supported by important vendors such as AWS-LC.
openssl_ver: [1.1.1w, 3.0.18, 3.3.5, 3.4.3, 3.5.4, 3.6.0]
# See Tools/ssl/make_ssl_data.py for notes on adding a new version
ssllib:
# See Tools/ssl/make_ssl_data.py for notes on adding a new version
## OpenSSL
# Keep 1.1.1w in our list despite it being upstream EOL and otherwise
# unsupported as it most resembles other 1.1.1-work-a-like ssl APIs
# supported by important vendors such as AWS-LC.
- { name: openssl, version: 1.1.1w }
- { name: openssl, version: 3.0.19 }
- { name: openssl, version: 3.3.6 }
- { name: openssl, version: 3.4.4 }
- { name: openssl, version: 3.5.5 }
- { name: openssl, version: 3.6.1 }
## AWS-LC
- { name: aws-lc, version: 1.68.0 }
env:
OPENSSL_VER: ${{ matrix.openssl_ver }}
SSLLIB_VER: ${{ matrix.ssllib.version }}
MULTISSL_DIR: ${{ github.workspace }}/multissl
OPENSSL_DIR: ${{ github.workspace }}/multissl/openssl/${{ matrix.openssl_ver }}
LD_LIBRARY_PATH: ${{ github.workspace }}/multissl/openssl/${{ matrix.openssl_ver }}/lib
SSLLIB_DIR: ${{ github.workspace }}/multissl/${{ matrix.ssllib.name }}/${{ matrix.ssllib.version }}
LD_LIBRARY_PATH: ${{ github.workspace }}/multissl/${{ matrix.ssllib.name }}/${{ matrix.ssllib.version }}/lib
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- name: Runner image version
@ -278,95 +300,37 @@ jobs:
run: echo "::add-matcher::.github/problem-matchers/gcc.json"
- name: Install dependencies
run: sudo ./.github/workflows/posix-deps-apt.sh
- name: Configure OpenSSL env vars
run: |
echo "MULTISSL_DIR=${GITHUB_WORKSPACE}/multissl" >> "$GITHUB_ENV"
echo "OPENSSL_DIR=${GITHUB_WORKSPACE}/multissl/openssl/${OPENSSL_VER}" >> "$GITHUB_ENV"
echo "LD_LIBRARY_PATH=${GITHUB_WORKSPACE}/multissl/openssl/${OPENSSL_VER}/lib" >> "$GITHUB_ENV"
- name: 'Restore OpenSSL build'
id: cache-openssl
uses: actions/cache@v5
- name: 'Restore SSL library build'
id: cache-ssl-lib
uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
with:
path: ./multissl/openssl/${{ env.OPENSSL_VER }}
key: ${{ matrix.os }}-multissl-openssl-${{ env.OPENSSL_VER }}
- name: Install OpenSSL
if: steps.cache-openssl.outputs.cache-hit != 'true'
run: python3 Tools/ssl/multissltests.py --steps=library --base-directory "$MULTISSL_DIR" --openssl "$OPENSSL_VER" --system Linux
- name: Add ccache to PATH
run: |
echo "PATH=/usr/lib/ccache:$PATH" >> "$GITHUB_ENV"
- name: Configure CPython
run: ./configure CFLAGS="-fdiagnostics-format=json" --config-cache --enable-slower-safety --with-pydebug --with-openssl="$OPENSSL_DIR"
- name: Build CPython
run: make -j4
- name: Display build info
run: make pythoninfo
- name: SSL tests
run: ./python Lib/test/ssltests.py
build-ubuntu-ssltests-awslc:
name: 'Ubuntu SSL tests with AWS-LC'
runs-on: ${{ matrix.os }}
timeout-minutes: 60
needs: build-context
if: needs.build-context.outputs.run-ubuntu == 'true'
strategy:
fail-fast: false
matrix:
os: [ubuntu-24.04]
awslc_ver: [1.55.0]
env:
AWSLC_VER: ${{ matrix.awslc_ver}}
MULTISSL_DIR: ${{ github.workspace }}/multissl
OPENSSL_DIR: ${{ github.workspace }}/multissl/aws-lc/${{ matrix.awslc_ver }}
LD_LIBRARY_PATH: ${{ github.workspace }}/multissl/aws-lc/${{ matrix.awslc_ver }}/lib
steps:
- uses: actions/checkout@v6
with:
persist-credentials: false
- name: Runner image version
run: echo "IMAGE_OS_VERSION=${ImageOS}-${ImageVersion}" >> "$GITHUB_ENV"
- name: Register gcc problem matcher
run: echo "::add-matcher::.github/problem-matchers/gcc.json"
- name: Install dependencies
run: sudo ./.github/workflows/posix-deps-apt.sh
- name: Configure SSL lib env vars
run: |
echo "MULTISSL_DIR=${GITHUB_WORKSPACE}/multissl" >> "$GITHUB_ENV"
echo "OPENSSL_DIR=${GITHUB_WORKSPACE}/multissl/aws-lc/${AWSLC_VER}" >> "$GITHUB_ENV"
echo "LD_LIBRARY_PATH=${GITHUB_WORKSPACE}/multissl/aws-lc/${AWSLC_VER}/lib" >> "$GITHUB_ENV"
- name: 'Restore AWS-LC build'
id: cache-aws-lc
uses: actions/cache@v5
with:
path: ./multissl/aws-lc/${{ matrix.awslc_ver }}
key: ${{ matrix.os }}-multissl-aws-lc-${{ matrix.awslc_ver }}
- name: Install AWS-LC
if: steps.cache-aws-lc.outputs.cache-hit != 'true'
path: ./multissl/${{ matrix.ssllib.name }}/${{ matrix.ssllib.version }}
key: ${{ matrix.os }}-multissl-${{ matrix.ssllib.name }}-${{ matrix.ssllib.version }}
- name: Install SSL Library
if: steps.cache-ssl-lib.outputs.cache-hit != 'true'
run: |
python3 Tools/ssl/multissltests.py \
--steps=library \
--base-directory "$MULTISSL_DIR" \
--awslc ${{ matrix.awslc_ver }} \
'--${{ matrix.ssllib.name }}' '${{ matrix.ssllib.version }}' \
--system Linux
- name: Add ccache to PATH
run: |
echo "PATH=/usr/lib/ccache:$PATH" >> "$GITHUB_ENV"
- name: Configure CPython
run: |
./configure CFLAGS="-fdiagnostics-format=json" \
--config-cache \
--enable-slower-safety \
--with-pydebug \
--with-openssl="$OPENSSL_DIR" \
--with-openssl="$SSLLIB_DIR" \
--with-builtin-hashlib-hashes=blake2 \
--with-ssl-default-suites=openssl
- name: Build CPython
run: make -j
run: make -j4
- name: Display build info
run: make pythoninfo
- name: Verify python is linked to AWS-LC
run: ./python -c 'import ssl; print(ssl.OPENSSL_VERSION)' | grep AWS-LC
- name: Verify python is linked to the right lib
run: |
./python -c 'import ssl; print(ssl.OPENSSL_VERSION)' \
| grep -iE '${{ matrix.ssllib.name }}.*${{ matrix.ssllib.version }}'
- name: SSL tests
run: ./python Lib/test/ssltests.py
@ -380,17 +344,17 @@ jobs:
matrix:
include:
- arch: aarch64
runs-on: macos-14
runs-on: macos-26
- arch: x86_64
runs-on: ubuntu-24.04
runs-on: ${{ matrix.runs-on }}
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- name: Build and test
run: ./Android/android.py ci --fast-ci ${{ matrix.arch }}-linux-android
run: python3 Platforms/Android ci --fast-ci ${{ matrix.arch }}-linux-android
build-ios:
name: iOS
@ -399,7 +363,7 @@ jobs:
timeout-minutes: 60
runs-on: macos-14
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
@ -413,7 +377,13 @@ jobs:
sudo xcode-select --switch /Applications/Xcode_15.4.app
- name: Build and test
run: python3 Apple ci iOS --fast-ci --simulator 'iPhone SE (3rd generation),OS=17.5'
run: python3 Platforms/Apple ci iOS --fast-ci --simulator 'iPhone SE (3rd generation),OS=17.5'
build-emscripten:
name: 'Emscripten'
needs: build-context
if: needs.build-context.outputs.run-emscripten == 'true'
uses: ./.github/workflows/reusable-emscripten.yml
build-wasi:
name: 'WASI'
@ -428,10 +398,10 @@ jobs:
needs: build-context
if: needs.build-context.outputs.run-ubuntu == 'true'
env:
OPENSSL_VER: 3.0.18
OPENSSL_VER: 3.5.5
PYTHONSTRICTEXTENSIONBUILD: 1
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- name: Register gcc problem matcher
@ -445,16 +415,13 @@ jobs:
echo "LD_LIBRARY_PATH=${GITHUB_WORKSPACE}/multissl/openssl/${OPENSSL_VER}/lib" >> "$GITHUB_ENV"
- name: 'Restore OpenSSL build'
id: cache-openssl
uses: actions/cache@v5
uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
with:
path: ./multissl/openssl/${{ env.OPENSSL_VER }}
key: ${{ runner.os }}-multissl-openssl-${{ env.OPENSSL_VER }}
- name: Install OpenSSL
if: steps.cache-openssl.outputs.cache-hit != 'true'
run: python3 Tools/ssl/multissltests.py --steps=library --base-directory "$MULTISSL_DIR" --openssl "$OPENSSL_VER" --system Linux
- name: Add ccache to PATH
run: |
echo "PATH=/usr/lib/ccache:$PATH" >> "$GITHUB_ENV"
- name: Setup directory envs for out-of-tree builds
run: |
echo "CPYTHON_RO_SRCDIR=$(realpath -m "${GITHUB_WORKSPACE}"/../cpython-ro-srcdir)" >> "$GITHUB_ENV"
@ -495,7 +462,7 @@ jobs:
./python -m venv "$VENV_LOC" && "$VENV_PYTHON" -m pip install -r "${GITHUB_WORKSPACE}/Tools/requirements-hypothesis.txt"
- name: 'Restore Hypothesis database'
id: cache-hypothesis-database
uses: actions/cache@v5
uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
with:
path: ${{ env.CPYTHON_BUILDDIR }}/.hypothesis/
key: hypothesis-database-${{ github.head_ref || github.run_id }}
@ -522,7 +489,7 @@ jobs:
-x test_subprocess \
-x test_signal \
-x test_sysconfig
- uses: actions/upload-artifact@v6
- uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
if: always()
with:
name: hypothesis-example-db
@ -539,11 +506,11 @@ jobs:
matrix:
os: [ubuntu-24.04]
env:
OPENSSL_VER: 3.0.18
OPENSSL_VER: 3.5.5
PYTHONSTRICTEXTENSIONBUILD: 1
ASAN_OPTIONS: detect_leaks=0:allocator_may_return_null=1:handle_segv=0
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- name: Runner image version
@ -553,7 +520,7 @@ jobs:
- name: Install dependencies
run: sudo ./.github/workflows/posix-deps-apt.sh
- name: Set up GCC-10 for ASAN
uses: egor-tensin/setup-gcc@v2
uses: egor-tensin/setup-gcc@a2861a8b8538f49cf2850980acccf6b05a1b2ae4 # v2.0
with:
version: 10
- name: Configure OpenSSL env vars
@ -563,18 +530,15 @@ jobs:
echo "LD_LIBRARY_PATH=${GITHUB_WORKSPACE}/multissl/openssl/${OPENSSL_VER}/lib" >> "$GITHUB_ENV"
- name: 'Restore OpenSSL build'
id: cache-openssl
uses: actions/cache@v5
uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
with:
path: ./multissl/openssl/${{ env.OPENSSL_VER }}
key: ${{ matrix.os }}-multissl-openssl-${{ env.OPENSSL_VER }}
- name: Install OpenSSL
if: steps.cache-openssl.outputs.cache-hit != 'true'
run: python3 Tools/ssl/multissltests.py --steps=library --base-directory "$MULTISSL_DIR" --openssl "$OPENSSL_VER" --system Linux
- name: Add ccache to PATH
run: |
echo "PATH=/usr/lib/ccache:$PATH" >> "$GITHUB_ENV"
- name: Configure CPython
run: ./configure --config-cache --with-address-sanitizer --without-pymalloc
run: ./configure --config-cache --with-address-sanitizer --without-pymalloc --with-openssl="$OPENSSL_DIR"
- name: Build CPython
run: make -j4
- name: Display build info
@ -613,7 +577,7 @@ jobs:
needs: build-context
if: needs.build-context.outputs.run-ubuntu == 'true'
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- name: Runner image version
@ -649,6 +613,7 @@ jobs:
needs.build-context.outputs.run-ci-fuzz == 'true'
|| needs.build-context.outputs.run-ci-fuzz-stdlib == 'true'
permissions:
contents: read
security-events: write
strategy:
fail-fast: false
@ -698,9 +663,9 @@ jobs:
- build-windows-msi
- build-macos
- build-ubuntu
- build-ubuntu-ssltests-awslc
- build-ubuntu-ssltests-openssl
- build-ubuntu-ssltests
- build-ios
- build-emscripten
- build-wasi
- test-hypothesis
- build-asan
@ -715,9 +680,9 @@ jobs:
with:
allowed-failures: >-
build-android,
build-emscripten,
build-windows-msi,
build-ubuntu-ssltests-awslc,
build-ubuntu-ssltests-openssl,
build-ubuntu-ssltests,
test-hypothesis,
cifuzz,
allowed-skips: >-
@ -748,8 +713,7 @@ jobs:
!fromJSON(needs.build-context.outputs.run-ubuntu)
&& '
build-ubuntu,
build-ubuntu-ssltests-awslc,
build-ubuntu-ssltests-openssl,
build-ubuntu-ssltests,
test-hypothesis,
build-asan,
build-san,
@ -759,5 +723,6 @@ jobs:
}}
${{ !fromJSON(needs.build-context.outputs.run-android) && 'build-android,' || '' }}
${{ !fromJSON(needs.build-context.outputs.run-ios) && 'build-ios,' || '' }}
${{ !fromJSON(needs.build-context.outputs.run-emscripten) && 'build-emscripten,' || '' }}
${{ !fromJSON(needs.build-context.outputs.run-wasi) && 'build-wasi,' || '' }}
jobs: ${{ toJSON(needs) }}

2
.github/workflows/documentation-links.yml vendored
View file

@ -22,7 +22,7 @@ jobs:
timeout-minutes: 5
steps:
- uses: readthedocs/actions/preview@v1
- uses: readthedocs/actions/preview@b8bba1484329bda1a3abe986df7ebc80a8950333 # v1.5
with:
project-slug: "cpython-previews"
single-version: "true"

219
.github/workflows/jit.yml vendored
View file

@ -1,7 +1,7 @@
name: JIT
on:
pull_request:
paths:
paths: &paths
- '**jit**'
- 'Python/bytecodes.c'
- 'Python/optimizer*.c'
@ -12,16 +12,7 @@ on:
- '!**/*.md'
- '!**/*.ini'
push:
paths:
- '**jit**'
- 'Python/bytecodes.c'
- 'Python/optimizer*.c'
- 'Python/executor_cases.c.h'
- 'Python/optimizer_cases.c.h'
- '**_testinternalcapi**'
- '!Python/perf_jit_trampoline.c'
- '!**/*.md'
- '!**/*.ini'
paths: *paths
workflow_dispatch:
permissions:
@ -33,14 +24,15 @@ concurrency:
env:
FORCE_COLOR: 1
LLVM_VERSION: 21
jobs:
interpreter:
name: Interpreter (Debug)
runs-on: ubuntu-24.04
timeout-minutes: 90
timeout-minutes: 60
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- name: Build tier two interpreter
@ -50,11 +42,12 @@ jobs:
- name: Test tier two interpreter
run: |
./python -m test --multiprocess 0 --timeout 4500 --verbose2 --verbose3
jit:
windows:
name: ${{ matrix.target }} (${{ matrix.debug && 'Debug' || 'Release' }})
needs: interpreter
runs-on: ${{ matrix.runner }}
timeout-minutes: 90
timeout-minutes: 60
strategy:
fail-fast: false
matrix:
@ -62,57 +55,66 @@ jobs:
- i686-pc-windows-msvc/msvc
- x86_64-pc-windows-msvc/msvc
- aarch64-pc-windows-msvc/msvc
- x86_64-apple-darwin/clang
- aarch64-apple-darwin/clang
- x86_64-unknown-linux-gnu/gcc
- aarch64-unknown-linux-gnu/gcc
debug:
- true
- false
llvm:
- 21
include:
- target: i686-pc-windows-msvc/msvc
architecture: Win32
runner: windows-2022
runner: windows-2025-vs2026
- target: x86_64-pc-windows-msvc/msvc
architecture: x64
runner: windows-2022
runner: windows-2025-vs2026
- target: aarch64-pc-windows-msvc/msvc
architecture: ARM64
runner: windows-11-arm
- target: x86_64-apple-darwin/clang
architecture: x86_64
runner: macos-15-intel
- target: aarch64-apple-darwin/clang
architecture: aarch64
runner: macos-14
- target: x86_64-unknown-linux-gnu/gcc
architecture: x86_64
runner: ubuntu-24.04
- target: aarch64-unknown-linux-gnu/gcc
architecture: aarch64
runner: ubuntu-24.04-arm
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- uses: actions/setup-python@v6
- uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
with:
python-version: '3.11'
# PCbuild downloads LLVM automatically:
- name: Windows
if: runner.os == 'Windows'
- name: Build
run: |
./PCbuild/build.bat --experimental-jit ${{ matrix.debug && '-d' || '' }} -p ${{ matrix.architecture }}
- name: Test
run: |
./PCbuild/rt.bat ${{ matrix.debug && '-d' || '' }} -p ${{ matrix.architecture }} -q --multiprocess 0 --timeout 4500 --verbose2 --verbose3
- name: macOS
if: runner.os == 'macOS'
macos:
name: ${{ matrix.target }} (${{ matrix.debug && 'Debug' || 'Release' }})
runs-on: ${{ matrix.runner }}
timeout-minutes: 60
strategy:
fail-fast: false
matrix:
target:
- x86_64-apple-darwin/clang
- aarch64-apple-darwin/clang
debug:
- true
- false
include:
- target: x86_64-apple-darwin/clang
runner: macos-15-intel
- target: aarch64-apple-darwin/clang
runner: macos-15
steps:
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
with:
python-version: '3.11'
- name: Install LLVM
run: |
brew update
brew install llvm@${{ matrix.llvm }}
brew install llvm@${{ env.LLVM_VERSION }}
- name: Build
run: |
export SDKROOT="$(xcrun --show-sdk-path)"
# Set MACOSX_DEPLOYMENT_TARGET and -Werror=unguarded-availability to
# make sure we don't break downstream distributors (like uv):
@ -120,92 +122,83 @@ jobs:
export MACOSX_DEPLOYMENT_TARGET=10.15
./configure --enable-experimental-jit --enable-universalsdk --with-universal-archs=universal2 ${{ matrix.debug && '--with-pydebug' || '' }}
make all --jobs 4
- name: Test
run: |
./python.exe -m test --multiprocess 0 --timeout 4500 --verbose2 --verbose3
- name: Linux
if: runner.os == 'Linux'
linux:
name: ${{ matrix.target }} (${{ matrix.debug && 'Debug' || 'Release' }})
runs-on: ${{ matrix.runner }}
timeout-minutes: 60
strategy:
fail-fast: false
matrix:
target:
- x86_64-unknown-linux-gnu/gcc
- aarch64-unknown-linux-gnu/gcc
debug:
- true
- false
include:
- target: x86_64-unknown-linux-gnu/gcc
runner: ubuntu-24.04
- target: aarch64-unknown-linux-gnu/gcc
runner: ubuntu-24.04-arm
steps:
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
with:
python-version: '3.11'
- name: Build
run: |
sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" ./llvm.sh ${{ matrix.llvm }}
export PATH="$(llvm-config-${{ matrix.llvm }} --bindir):$PATH"
sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" ./llvm.sh ${{ env.LLVM_VERSION }}
export PATH="$(llvm-config-${{ env.LLVM_VERSION }} --bindir):$PATH"
./configure --enable-experimental-jit ${{ matrix.debug && '--with-pydebug' || '' }}
make all --jobs 4
./python -m test --multiprocess 0 --timeout 4500 --verbose2 --verbose3
jit-with-disabled-gil:
name: Free-Threaded (Debug)
needs: interpreter
runs-on: ubuntu-24.04
timeout-minutes: 90
strategy:
fail-fast: false
matrix:
llvm:
- 21
steps:
- uses: actions/checkout@v6
with:
persist-credentials: false
- uses: actions/setup-python@v6
with:
python-version: '3.11'
- name: Build with JIT enabled and GIL disabled
run: |
sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" ./llvm.sh ${{ matrix.llvm }}
export PATH="$(llvm-config-${{ matrix.llvm }} --bindir):$PATH"
./configure --enable-experimental-jit --with-pydebug --disable-gil
make all --jobs 4
- name: Run tests
- name: Test
run: |
./python -m test --multiprocess 0 --timeout 4500 --verbose2 --verbose3
continue-on-error: true
no-opt-jit:
name: JIT without optimizations (Debug)
needs: interpreter
linux-extras:
name: ${{ matrix.name }}
runs-on: ubuntu-24.04
timeout-minutes: 90
timeout-minutes: 60
strategy:
fail-fast: false
matrix:
llvm:
- 21
include:
- name: Free-Threaded (Debug)
configure_flags: --enable-experimental-jit --with-pydebug --disable-gil
continue_on_error: true
- name: JIT without optimizations (Debug)
configure_flags: --enable-experimental-jit --with-pydebug
test_env: "PYTHON_UOPS_OPTIMIZE=0"
- name: JIT with tail calling interpreter
configure_flags: --enable-experimental-jit --with-tail-call-interp --with-pydebug
use_clang: true
run_tests: false
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- uses: actions/setup-python@v6
- uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
with:
python-version: '3.11'
- name: Build with JIT
- name: Build
run: |
sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" ./llvm.sh ${{ matrix.llvm }}
export PATH="$(llvm-config-${{ matrix.llvm }} --bindir):$PATH"
./configure --enable-experimental-jit --with-pydebug
sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" ./llvm.sh ${{ env.LLVM_VERSION }}
export PATH="$(llvm-config-${{ env.LLVM_VERSION }} --bindir):$PATH"
if [ "${{ matrix.use_clang }}" = "true" ]; then
export CC=clang-${{ env.LLVM_VERSION }}
fi
./configure ${{ matrix.configure_flags }}
make all --jobs 4
- name: Run tests without optimizations
- name: Test
if: matrix.run_tests != false
run: |
PYTHON_UOPS_OPTIMIZE=0 ./python -m test --multiprocess 0 --timeout 4500 --verbose2 --verbose3
tail-call-jit:
name: JIT with tail calling interpreter
needs: interpreter
runs-on: ubuntu-24.04
timeout-minutes: 90
strategy:
fail-fast: false
matrix:
llvm:
- 21
steps:
- uses: actions/checkout@v6
with:
persist-credentials: false
- uses: actions/setup-python@v6
with:
python-version: '3.11'
- name: Build with JIT and tailcall
run: |
sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" ./llvm.sh ${{ matrix.llvm }}
export PATH="$(llvm-config-${{ matrix.llvm }} --bindir):$PATH"
CC=clang-${{ matrix.llvm }} ./configure --enable-experimental-jit --with-tail-call-interp --with-pydebug
make all --jobs 4
${{ matrix.test_env }} ./python -m test --multiprocess 0 --timeout 4500 --verbose2 --verbose3
continue-on-error: ${{ matrix.continue_on_error }}

4
.github/workflows/lint.yml vendored
View file

@ -19,7 +19,7 @@ jobs:
timeout-minutes: 10
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- uses: j178/prek-action@v1
- uses: j178/prek-action@0bb87d7f00b0c99306c8bcb8b8beba1eb581c037 # v1.1.1

5
.github/workflows/mypy.yml vendored
View file

@ -19,6 +19,7 @@ on:
- "Tools/build/consts_getter.py"
- "Tools/build/deepfreeze.py"
- "Tools/build/generate-build-details.py"
- "Tools/build/generate_levenshtein_examples.py"
- "Tools/build/generate_sbom.py"
- "Tools/build/generate_stdlib_module_names.py"
- "Tools/build/mypy.ini"
@ -65,10 +66,10 @@ jobs:
"Tools/peg_generator",
]
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- uses: actions/setup-python@v6
- uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
with:
python-version: "3.13"
cache: pip

10
.github/workflows/new-bugs-announce-notifier.yml vendored
View file

@ -6,19 +6,21 @@ on:
- opened
permissions:
issues: read
contents: read
jobs:
notify-new-bugs-announce:
runs-on: ubuntu-latest
permissions:
issues: read
timeout-minutes: 10
steps:
- uses: actions/setup-node@v6
- uses: actions/setup-node@53b83947a5a98c8d113130e565377fae1a50d02f # v6.3.0
with:
node-version: 20
- run: npm install mailgun.js form-data
- name: Send notification
uses: actions/github-script@v8
uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8.0.0
env:
MAILGUN_API_KEY: ${{ secrets.MAILGUN_PYTHON_ORG_MAILGUN_KEY }}
with:
@ -44,7 +46,7 @@ jobs:
// We need to truncate the body size, because the max size for
// the whole payload is 16kb. We want to be safe and assume that
// body can take up to ~8kb of space.
body : issue.data.body.substring(0, 8000)
body : (issue.data.body || "").substring(0, 8000)
};
const data = {

5
.github/workflows/posix-deps-apt.sh vendored
View file

@ -1,10 +1,9 @@
#!/bin/sh
apt-get update
apt-get -yq install \
apt-get -yq --no-install-recommends install \
build-essential \
pkg-config \
ccache \
cmake \
gdb \
lcov \
@ -32,4 +31,4 @@ apt-get -yq install \
# https://deb.sury.org/
sudo add-apt-repository ppa:ondrej/php
apt-get update
apt-get -yq install libmpdec-dev
apt-get -yq --no-install-recommends install libmpdec-dev

2
.github/workflows/regen-abidump.sh vendored
View file

@ -2,7 +2,7 @@ set -ex
export DEBIAN_FRONTEND=noninteractive
./.github/workflows/posix-deps-apt.sh
apt-get install -yq abigail-tools python3
apt-get install -yq --no-install-recommends abigail-tools python3
export CFLAGS="-g3 -O0"
./configure --enable-shared && make
make regen-abidump

11
.github/workflows/require-pr-label.yml vendored
View file

@ -4,6 +4,9 @@ on:
pull_request:
types: [opened, reopened, labeled, unlabeled, synchronize]
permissions:
contents: read
jobs:
label-dnm:
name: DO-NOT-MERGE
@ -15,7 +18,7 @@ jobs:
steps:
- name: Check there's no DO-NOT-MERGE
uses: mheap/github-action-required-labels@v5
uses: mheap/github-action-required-labels@0ac283b4e65c1fb28ce6079dea5546ceca98ccbe # v5.5.2
with:
mode: exactly
count: 0
@ -33,7 +36,7 @@ jobs:
steps:
# Check that the PR is not awaiting changes from the author due to previous review.
- name: Check there's no required changes
uses: mheap/github-action-required-labels@v5
uses: mheap/github-action-required-labels@0ac283b4e65c1fb28ce6079dea5546ceca98ccbe # v5.5.2
with:
mode: exactly
count: 0
@ -42,7 +45,7 @@ jobs:
awaiting change review
- id: is-feature
name: Check whether this PR is a feature (contains a "type-feature" label)
uses: mheap/github-action-required-labels@v5
uses: mheap/github-action-required-labels@0ac283b4e65c1fb28ce6079dea5546ceca98ccbe # v5.5.2
with:
mode: exactly
count: 1
@ -53,7 +56,7 @@ jobs:
- id: awaiting-merge
if: steps.is-feature.outputs.status == 'success'
name: Check for complete review
uses: mheap/github-action-required-labels@v5
uses: mheap/github-action-required-labels@0ac283b4e65c1fb28ce6079dea5546ceca98ccbe # v5.5.2
with:
mode: exactly
count: 1

4
.github/workflows/reusable-check-c-api-docs.yml vendored
View file

@ -15,10 +15,10 @@ jobs:
runs-on: ubuntu-latest
timeout-minutes: 5
steps:
- uses: actions/checkout@v4
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- uses: actions/setup-python@v5
- uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
with:
python-version: '3.x'
- name: Check for undocumented C APIs

67
.github/workflows/reusable-check-html-ids.yml vendored Normal file
View file

@ -0,0 +1,67 @@
name: Reusable check HTML IDs
on:
workflow_call:
permissions:
contents: read
env:
FORCE_COLOR: 1
jobs:
check-html-ids:
name: 'Check for removed HTML IDs'
runs-on: ubuntu-latest
timeout-minutes: 30
steps:
- name: 'Check out PR head'
uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
ref: ${{ github.event.pull_request.head.sha }}
- name: 'Find merge base'
id: merge-base
run: |
BASE="${{ github.event.pull_request.base.sha }}"
HEAD="${{ github.event.pull_request.head.sha }}"
git fetch --depth=$((${{ github.event.pull_request.commits }} + 10)) --no-tags origin "$BASE" "$HEAD"
if ! MERGE_BASE=$(git merge-base "$BASE" "$HEAD" 2>/dev/null); then
git fetch --deepen=1 --no-tags origin "$BASE" "$HEAD"
OLDEST=$(git rev-list --reflog --max-parents=0 --reverse "${BASE}^" "${HEAD}^" | head -1)
TIMESTAMP=$(git show --format=%at --no-patch "$OLDEST")
git fetch --shallow-since="$TIMESTAMP" --no-tags origin "$BASE" "$HEAD"
MERGE_BASE=$(git merge-base "$BASE" "$HEAD")
fi
echo "sha=$MERGE_BASE" >> "$GITHUB_OUTPUT"
- name: 'Create worktree at merge base'
env:
MERGE_BASE: ${{ steps.merge-base.outputs.sha }}
run: git worktree add /tmp/merge-base "$MERGE_BASE" --detach
- name: 'Set up Python'
uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
with:
python-version: '3'
cache: 'pip'
cache-dependency-path: 'Doc/requirements.txt'
- name: 'Install build dependencies'
run: make -C /tmp/merge-base/Doc/ venv
- name: 'Build HTML documentation'
run: make -C /tmp/merge-base/Doc/ SPHINXOPTS="--quiet" html
- name: 'Collect HTML IDs'
run: python Doc/tools/check-html-ids.py collect /tmp/merge-base/Doc/build/html -o /tmp/html-ids-base.json.gz
- name: 'Download PR head HTML IDs'
uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
with:
name: html-ids-head.json.gz
path: /tmp
- name: 'Check for removed HTML IDs'
run: |
# shellcheck disable=SC2046
python Doc/tools/check-html-ids.py -v check \
/tmp/html-ids-base.json.gz /tmp/html-ids-head.json.gz \
$([ -f Doc/tools/removed-ids.txt ] && echo "--exclude-file Doc/tools/removed-ids.txt")

11
.github/workflows/reusable-cifuzz.yml vendored
View file

@ -13,6 +13,9 @@ on:
required: true
type: string
permissions:
contents: read
jobs:
cifuzz:
name: ${{ inputs.oss-fuzz-project-name }} (${{ inputs.sanitizer }})
@ -21,12 +24,12 @@ jobs:
steps:
- name: Build fuzzers (${{ inputs.sanitizer }})
id: build
uses: google/oss-fuzz/infra/cifuzz/actions/build_fuzzers@master
uses: google/oss-fuzz/infra/cifuzz/actions/build_fuzzers@ed23f8af80ff82b25ca67cd9b101e690b8897b3f # master
with:
oss-fuzz-project-name: ${{ inputs.oss-fuzz-project-name }}
sanitizer: ${{ inputs.sanitizer }}
- name: Run fuzzers (${{ inputs.sanitizer }})
uses: google/oss-fuzz/infra/cifuzz/actions/run_fuzzers@master
uses: google/oss-fuzz/infra/cifuzz/actions/run_fuzzers@ed23f8af80ff82b25ca67cd9b101e690b8897b3f # master
with:
fuzz-seconds: 600
oss-fuzz-project-name: ${{ inputs.oss-fuzz-project-name }}
@ -34,13 +37,13 @@ jobs:
sanitizer: ${{ inputs.sanitizer }}
- name: Upload crash
if: failure() && steps.build.outcome == 'success'
uses: actions/upload-artifact@v6
uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
with:
name: ${{ inputs.sanitizer }}-artifacts
path: ./out/artifacts
- name: Upload SARIF
if: always() && steps.build.outcome == 'success'
uses: github/codeql-action/upload-sarif@v4
uses: github/codeql-action/upload-sarif@38697555549f1db7851b81482ff19f1fa5c4fedc # v4.34.1
with:
sarif_file: cifuzz-sarif/results.sarif
checkout_path: cifuzz-sarif

11
.github/workflows/reusable-context.yml vendored
View file

@ -41,6 +41,9 @@ on: # yamllint disable-line rule:truthy
run-ubuntu:
description: Whether to run the Ubuntu tests
value: ${{ jobs.compute-changes.outputs.run-ubuntu }} # bool
run-emscripten:
description: Whether to run the Emscripten tests
value: ${{ jobs.compute-changes.outputs.run-emscripten }} # bool
run-wasi:
description: Whether to run the WASI tests
value: ${{ jobs.compute-changes.outputs.run-wasi }} # bool
@ -51,6 +54,9 @@ on: # yamllint disable-line rule:truthy
description: Whether to run the Windows tests
value: ${{ jobs.compute-changes.outputs.run-windows-tests }} # bool
permissions:
contents: read
jobs:
compute-changes:
name: Create context from changed files
@ -65,19 +71,20 @@ jobs:
run-macos: ${{ steps.changes.outputs.run-macos }}
run-tests: ${{ steps.changes.outputs.run-tests }}
run-ubuntu: ${{ steps.changes.outputs.run-ubuntu }}
run-emscripten: ${{ steps.changes.outputs.run-emscripten }}
run-wasi: ${{ steps.changes.outputs.run-wasi }}
run-windows-msi: ${{ steps.changes.outputs.run-windows-msi }}
run-windows-tests: ${{ steps.changes.outputs.run-windows-tests }}
steps:
- name: Set up Python
uses: actions/setup-python@v6
uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
with:
python-version: "3"
- run: >-
echo '${{ github.event_name }}'
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
ref: >-

30
.github/workflows/reusable-docs.yml vendored
View file

@ -27,7 +27,7 @@ jobs:
refspec_pr: '+${{ github.event.pull_request.head.sha }}:remotes/origin/${{ github.event.pull_request.head.ref }}'
steps:
- name: 'Check out latest PR branch commit'
uses: actions/checkout@v6
uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
ref: >-
@ -52,7 +52,7 @@ jobs:
git fetch origin "${refspec_base}" --shallow-since="${DATE}" \
--no-tags --prune --no-recurse-submodules
- name: 'Set up Python'
uses: actions/setup-python@v6
uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
with:
python-version: '3'
cache: 'pip'
@ -75,6 +75,22 @@ jobs:
--fail-if-regression \
--fail-if-improved \
--fail-if-new-news-nit
- name: 'Collect HTML IDs'
if: github.event_name == 'pull_request'
run: python Doc/tools/check-html-ids.py collect Doc/build/html -o Doc/build/html-ids-head.json.gz
- name: 'Upload HTML IDs'
if: github.event_name == 'pull_request'
uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
with:
name: html-ids-head
path: Doc/build/html-ids-head.json.gz
archive: false
check-html-ids:
name: 'Check for removed HTML IDs'
needs: build-doc
if: github.event_name == 'pull_request'
uses: ./.github/workflows/reusable-check-html-ids.yml
# Run "doctest" on HEAD as new syntax doesn't exist in the latest stable release
doctest:
@ -82,17 +98,17 @@ jobs:
runs-on: ubuntu-24.04
timeout-minutes: 60
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- uses: actions/cache@v5
- uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
with:
path: ~/.cache/pip
key: ubuntu-doc-${{ hashFiles('Doc/requirements.txt') }}
restore-keys: |
ubuntu-doc-
- name: 'Install Dependencies'
run: sudo ./.github/workflows/posix-deps-apt.sh && sudo apt-get install wamerican
run: sudo ./.github/workflows/posix-deps-apt.sh && sudo apt-get install --no-install-recommends wamerican
- name: 'Configure CPython'
run: ./configure --with-pydebug
- name: 'Build CPython'
@ -108,11 +124,11 @@ jobs:
runs-on: ubuntu-latest
timeout-minutes: 30
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- name: 'Set up Python'
uses: actions/setup-python@v6
uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
with:
python-version: '3'
cache: 'pip'

77
.github/workflows/reusable-emscripten.yml vendored Normal file
View file

@ -0,0 +1,77 @@
name: Reusable Emscripten
on:
workflow_call:
permissions:
contents: read
env:
FORCE_COLOR: 1
jobs:
build-emscripten-reusable:
name: 'build and test'
runs-on: ubuntu-24.04
timeout-minutes: 40
steps:
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- name: "Read Emscripten config"
id: emscripten-config
shell: python
run: |
import hashlib
import json
import os
import tomllib
from pathlib import Path
config = tomllib.loads(Path("Platforms/emscripten/config.toml").read_text())
h = hashlib.sha256()
h.update(json.dumps(config["dependencies"], sort_keys=True).encode())
h.update(Path("Platforms/emscripten/make_libffi.sh").read_bytes())
h.update(b'1') # Update to explicitly bust cache
emsdk_cache = Path(os.environ["RUNNER_TEMP"]) / "emsdk-cache"
with open(os.environ["GITHUB_OUTPUT"], "a") as f:
f.write(f"emscripten-version={config['emscripten-version']}\n")
f.write(f"node-version={config['node-version']}\n")
f.write(f"deps-hash={h.hexdigest()}\n")
with open(os.environ["GITHUB_ENV"], "a") as f:
f.write(f"EMSDK_CACHE={emsdk_cache}\n")
- name: "Install Node.js"
uses: actions/setup-node@53b83947a5a98c8d113130e565377fae1a50d02f # v6.3.0
with:
node-version: ${{ steps.emscripten-config.outputs.node-version }}
- name: "Cache Emscripten SDK"
id: emsdk-cache
uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
with:
path: ${{ env.EMSDK_CACHE }}
key: emsdk-${{ steps.emscripten-config.outputs.emscripten-version }}-${{ steps.emscripten-config.outputs.deps-hash }}
restore-keys: emsdk-${{ steps.emscripten-config.outputs.emscripten-version }}
- name: "Install Python"
uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
with:
python-version: '3.x'
- name: "Runner image version"
run: echo "IMAGE_OS_VERSION=${ImageOS}-${ImageVersion}" >> "$GITHUB_ENV"
- name: "Install Emscripten"
run: python3 Platforms/emscripten install-emscripten
- name: "Configure build Python"
run: python3 Platforms/emscripten configure-build-python -- --config-cache --with-pydebug
- name: "Make build Python"
run: python3 Platforms/emscripten make-build-python
- name: "Make dependencies"
run: >-
python3 Platforms/emscripten make-dependencies
${{ steps.emsdk-cache.outputs.cache-hit == 'true' && '--check-up-to-date' || '' }}
- name: "Configure host Python"
run: python3 Platforms/emscripten configure-host --host-runner node -- --config-cache
- name: "Make host Python"
run: python3 Platforms/emscripten make-host
- name: "Display build info"
run: python3 Platforms/emscripten run --pythoninfo
- name: "Test"
run: python3 Platforms/emscripten run --test

9
.github/workflows/reusable-macos.yml vendored
View file

@ -12,6 +12,9 @@ on:
required: true
type: string
permissions:
contents: read
env:
FORCE_COLOR: 1
@ -28,14 +31,14 @@ jobs:
PYTHONSTRICTEXTENSIONBUILD: 1
TERM: linux
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- name: Runner image version
run: echo "IMAGE_OS_VERSION=${ImageOS}-${ImageVersion}" >> "$GITHUB_ENV"
- name: Install Homebrew dependencies
run: |
brew install pkg-config openssl@3.0 xz gdbm tcl-tk@9 make
brew install pkg-config openssl@3.5 xz gdbm tcl-tk@9 make
# Because alternate versions are not symlinked into place by default:
brew link --overwrite tcl-tk@9
- name: Configure CPython
@ -50,7 +53,7 @@ jobs:
--enable-safety \
${{ inputs.free-threading && '--disable-gil' || '' }} \
--prefix=/opt/python-dev \
--with-openssl="$(brew --prefix openssl@3.0)"
--with-openssl="$(brew --prefix openssl@3.5)"
- name: Build CPython
if : ${{ inputs.free-threading || inputs.os != 'macos-15-intel' }}
run: gmake -j8

29
.github/workflows/reusable-san.yml vendored
View file

@ -12,6 +12,9 @@ on:
type: boolean
default: false
permissions:
contents: read
env:
FORCE_COLOR: 1
@ -26,7 +29,7 @@ jobs:
runs-on: ubuntu-24.04
timeout-minutes: 60
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- name: Runner image version
@ -37,17 +40,15 @@ jobs:
# Install clang
wget https://apt.llvm.org/llvm.sh
chmod +x llvm.sh
sudo ./llvm.sh 20
sudo update-alternatives --install /usr/bin/clang clang /usr/bin/clang-20 100
sudo update-alternatives --set clang /usr/bin/clang-20
sudo update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-20 100
sudo update-alternatives --set clang++ /usr/bin/clang++-20
if [ "${SANITIZER}" = "TSan" ]; then
sudo ./llvm.sh 17 # gh-121946: llvm-18 package is temporarily broken
sudo update-alternatives --install /usr/bin/clang clang /usr/bin/clang-17 100
sudo update-alternatives --set clang /usr/bin/clang-17
sudo update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-17 100
sudo update-alternatives --set clang++ /usr/bin/clang++-17
# Reduce ASLR to avoid TSan crashing
sudo sysctl -w vm.mmap_rnd_bits=28
else
sudo ./llvm.sh 20
fi
- name: Sanitizer option setup
@ -59,16 +60,13 @@ jobs:
|| ''
}}.txt handle_segv=0" >> "$GITHUB_ENV"
else
echo "UBSAN_OPTIONS=${SAN_LOG_OPTION}" >> "$GITHUB_ENV"
echo "UBSAN_OPTIONS=${SAN_LOG_OPTION} halt_on_error=1 suppressions=${GITHUB_WORKSPACE}/Tools/ubsan/suppressions.txt" >> "$GITHUB_ENV"
fi
echo "CC=clang" >> "$GITHUB_ENV"
echo "CXX=clang++" >> "$GITHUB_ENV"
env:
SANITIZER: ${{ inputs.sanitizer }}
SAN_LOG_OPTION: log_path=${{ github.workspace }}/san_log
- name: Add ccache to PATH
run: |
echo "PATH=/usr/lib/ccache:$PATH" >> "$GITHUB_ENV"
- name: Configure CPython
run: >-
./configure
@ -76,7 +74,7 @@ jobs:
${{
inputs.sanitizer == 'TSan'
&& '--with-thread-sanitizer'
|| '--with-undefined-behavior-sanitizer'
|| '--with-undefined-behavior-sanitizer --with-strict-overflow'
}}
--with-pydebug
${{ fromJSON(inputs.free-threading) && '--disable-gil' || '' }}
@ -84,10 +82,13 @@ jobs:
run: make -j4
- name: Display build info
run: make pythoninfo
# test_{capi,faulthandler} are skipped under UBSan because
# they raise signals that UBSan with halt_on_error=1 intercepts.
- name: Tests
run: >-
./python -m test
${{ inputs.sanitizer == 'TSan' && '--tsan' || '' }}
${{ inputs.sanitizer == 'UBSan' && '-x test_capi -x test_faulthandler' || '' }}
-j4
- name: Parallel tests
if: >-
@ -99,7 +100,7 @@ jobs:
run: find "${GITHUB_WORKSPACE}" -name 'san_log.*' | xargs head -n 1000
- name: Archive logs
if: always()
uses: actions/upload-artifact@v6
uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
with:
name: >-
${{ inputs.sanitizer }}-logs-${{

23
.github/workflows/reusable-ubuntu.yml vendored
View file

@ -17,6 +17,14 @@ on:
description: OS to run the job
required: true
type: string
test-opts:
description: Extra options to pass to the test runner via TESTOPTS
required: false
type: string
default: ''
permissions:
contents: read
env:
FORCE_COLOR: 1
@ -27,11 +35,11 @@ jobs:
runs-on: ${{ inputs.os }}
timeout-minutes: 60
env:
OPENSSL_VER: 3.0.18
OPENSSL_VER: 3.5.5
PYTHONSTRICTEXTENSIONBUILD: 1
TERM: linux
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- name: Register gcc problem matcher
@ -42,7 +50,7 @@ jobs:
if: ${{ fromJSON(inputs.bolt-optimizations) }}
run: |
sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" ./llvm.sh 19
sudo apt-get install bolt-19
sudo apt-get install --no-install-recommends bolt-19
echo PATH="$(llvm-config-19 --bindir):$PATH" >> $GITHUB_ENV
- name: Configure OpenSSL env vars
run: |
@ -51,16 +59,13 @@ jobs:
echo "LD_LIBRARY_PATH=${GITHUB_WORKSPACE}/multissl/openssl/${OPENSSL_VER}/lib" >> "$GITHUB_ENV"
- name: 'Restore OpenSSL build'
id: cache-openssl
uses: actions/cache@v5
uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
with:
path: ./multissl/openssl/${{ env.OPENSSL_VER }}
key: ${{ inputs.os }}-multissl-openssl-${{ env.OPENSSL_VER }}
- name: Install OpenSSL
if: steps.cache-openssl.outputs.cache-hit != 'true'
run: python3 Tools/ssl/multissltests.py --steps=library --base-directory "$MULTISSL_DIR" --openssl "$OPENSSL_VER" --system Linux
- name: Add ccache to PATH
run: |
echo "PATH=/usr/lib/ccache:$PATH" >> "$GITHUB_ENV"
- name: Setup directory envs for out-of-tree builds
run: |
echo "CPYTHON_RO_SRCDIR=$(realpath -m "${GITHUB_WORKSPACE}"/../cpython-ro-srcdir)" >> "$GITHUB_ENV"
@ -111,4 +116,6 @@ jobs:
run: sudo mount "$CPYTHON_RO_SRCDIR" -oremount,rw
- name: Tests
working-directory: ${{ env.CPYTHON_BUILDDIR }}
run: xvfb-run make ci
run: xvfb-run make ci EXTRATESTOPTS="${TEST_OPTS}"
env:
TEST_OPTS: ${{ inputs.test-opts }}

42
.github/workflows/reusable-wasi.yml vendored
View file

@ -3,6 +3,9 @@ name: Reusable WASI
on:
workflow_call:
permissions:
contents: read
env:
FORCE_COLOR: 1
@ -13,35 +16,36 @@ jobs:
timeout-minutes: 60
env:
WASMTIME_VERSION: 38.0.3
WASI_SDK_VERSION: 29
WASI_SDK_PATH: /opt/wasi-sdk
CROSS_BUILD_PYTHON: cross-build/build
CROSS_BUILD_WASI: cross-build/wasm32-wasip1
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
# No problem resolver registered as one doesn't currently exist for Clang.
- name: "Install wasmtime"
uses: bytecodealliance/actions/wasmtime/setup@v1
uses: bytecodealliance/actions/wasmtime/setup@9152e710e9f7182e4c29ad218e4f335a7b203613 # v1.1.3
with:
version: ${{ env.WASMTIME_VERSION }}
- name: "Restore WASI SDK"
id: cache-wasi-sdk
uses: actions/cache@v5
with:
path: ${{ env.WASI_SDK_PATH }}
key: ${{ runner.os }}-wasi-sdk-${{ env.WASI_SDK_VERSION }}
- name: "Install WASI SDK" # Hard-coded to x64.
if: steps.cache-wasi-sdk.outputs.cache-hit != 'true'
- name: "Read WASI SDK version"
id: wasi-sdk-version
run: |
mkdir "${WASI_SDK_PATH}" && \
curl -s -S --location "https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-${WASI_SDK_VERSION}/wasi-sdk-${WASI_SDK_VERSION}.0-arm64-linux.tar.gz" | \
tar --strip-components 1 --directory "${WASI_SDK_PATH}" --extract --gunzip
- name: "Add ccache to PATH"
run: echo "PATH=/usr/lib/ccache:$PATH" >> "$GITHUB_ENV"
import tomllib
from pathlib import Path
import os
config = tomllib.loads(Path("Platforms/WASI/config.toml").read_text())
version = config["targets"]["wasi-sdk"]
with open(os.environ["GITHUB_OUTPUT"], "a") as f:
f.write(f"version={version}\n")
shell: python
- name: "Install WASI SDK"
id: install-wasi-sdk
uses: bytecodealliance/setup-wasi-sdk-action@b2de090b44eb70013ee96b393727d473b35e1728
with:
version: ${{ steps.wasi-sdk-version.outputs.version }}
add-to-path: false
- name: "Install Python"
uses: actions/setup-python@v6
uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
with:
python-version: '3.x'
- name: "Runner image version"
@ -53,6 +57,8 @@ jobs:
- name: "Configure host"
# `--with-pydebug` inferred from configure-build-python
run: python3 Platforms/WASI configure-host -- --config-cache
env:
WASI_SDK_PATH: ${{ steps.install-wasi-sdk.outputs.wasi-sdk-path }}
- name: "Make host"
run: python3 Platforms/WASI make-host
- name: "Display build info"

4
.github/workflows/reusable-windows-msi.yml vendored
View file

@ -17,13 +17,13 @@ env:
jobs:
build:
name: installer for ${{ inputs.arch }}
runs-on: ${{ inputs.arch == 'arm64' && 'windows-11-arm' || 'windows-2022' }}
runs-on: ${{ inputs.arch == 'arm64' && 'windows-11-arm' || 'windows-2025-vs2026' }}
timeout-minutes: 60
env:
ARCH: ${{ inputs.arch }}
IncludeFreethreaded: true
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- name: Build CPython installer

21
.github/workflows/reusable-windows.yml vendored
View file

@ -12,6 +12,13 @@ on:
required: false
type: boolean
default: false
interpreter:
description: Which interpreter to build (switch-case or tail-call)
required: true
type: string
permissions:
contents: read
env:
FORCE_COLOR: 1
@ -20,22 +27,25 @@ env:
jobs:
build:
name: Build and test (${{ inputs.arch }})
runs-on: ${{ inputs.arch == 'arm64' && 'windows-11-arm' || 'windows-2022' }}
name: Build and test (${{ inputs.arch }}, ${{ inputs.interpreter }})
runs-on: ${{ inputs.arch == 'arm64' && 'windows-11-arm' || 'windows-2025-vs2026' }}
timeout-minutes: 60
env:
ARCH: ${{ inputs.arch }}
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- name: Register MSVC problem matcher
if: inputs.arch != 'Win32'
run: echo "::add-matcher::.github/problem-matchers/msvc.json"
- name: Build CPython
# msvc::musttail is not supported for debug builds, so we have to
# switch to release.
run: >-
.\\PCbuild\\build.bat
-e -d -v
-e -v
${{ inputs.interpreter == 'switch-case' && '-d' || '--tail-call-interp -c Release' }}
-p "${ARCH}"
${{ fromJSON(inputs.free-threading) && '--disable-gil' || '' }}
shell: bash
@ -45,6 +55,7 @@ jobs:
run: >-
.\\PCbuild\\rt.bat
-p "${ARCH}"
-d -q --fast-ci
-q --fast-ci
${{ inputs.interpreter == 'switch-case' && '-d' || '' }}
${{ fromJSON(inputs.free-threading) && '--disable-gil' || '' }}
shell: bash

6
.github/workflows/stale.yml vendored
View file

@ -4,17 +4,21 @@ on:
schedule:
- cron: "0 */6 * * *"
permissions:
contents: read
jobs:
stale:
if: github.repository_owner == 'python'
runs-on: ubuntu-latest
permissions:
actions: write
pull-requests: write
timeout-minutes: 10
steps:
- name: "Check PRs"
uses: actions/stale@v9
uses: actions/stale@b5d41d4e1d5dceea10e7104786b73624c18a190f # v10.2.0
with:
repo-token: ${{ secrets.GITHUB_TOKEN }}
stale-pr-message: 'This PR is stale because it has been open for 30 days with no activity.'

131
.github/workflows/tail-call.yml vendored
View file

@ -1,19 +1,14 @@
name: Tail calling interpreter
on:
pull_request:
paths:
paths: &paths
- '.github/workflows/tail-call.yml'
- 'Python/bytecodes.c'
- 'Python/ceval.c'
- 'Python/ceval_macros.h'
- 'Python/generated_cases.c.h'
push:
paths:
- '.github/workflows/tail-call.yml'
- 'Python/bytecodes.c'
- 'Python/ceval.c'
- 'Python/ceval_macros.h'
- 'Python/generated_cases.c.h'
paths: *paths
workflow_dispatch:
permissions:
@ -25,107 +20,73 @@ concurrency:
env:
FORCE_COLOR: 1
LLVM_VERSION: 21
jobs:
tail-call:
macos:
name: ${{ matrix.target }}
runs-on: ${{ matrix.runner }}
timeout-minutes: 90
timeout-minutes: 60
strategy:
fail-fast: false
matrix:
target:
# Un-comment as we add support for more platforms for tail-calling interpreters.
# - i686-pc-windows-msvc/msvc
- x86_64-pc-windows-msvc/msvc
# - aarch64-pc-windows-msvc/msvc
- x86_64-apple-darwin/clang
- aarch64-apple-darwin/clang
- x86_64-unknown-linux-gnu/gcc
- aarch64-unknown-linux-gnu/gcc
- free-threading
llvm:
- 20
include:
# - target: i686-pc-windows-msvc/msvc
# architecture: Win32
# runner: windows-2022
- target: x86_64-pc-windows-msvc/msvc
architecture: x64
runner: windows-2022
# - target: aarch64-pc-windows-msvc/msvc
# architecture: ARM64
# runner: windows-2022
- target: x86_64-apple-darwin/clang
architecture: x86_64
runner: macos-15-intel
- target: aarch64-apple-darwin/clang
architecture: aarch64
runner: macos-14
- target: x86_64-unknown-linux-gnu/gcc
architecture: x86_64
runner: ubuntu-24.04
- target: aarch64-unknown-linux-gnu/gcc
architecture: aarch64
runner: ubuntu-24.04-arm
- target: free-threading
architecture: x86_64
runner: ubuntu-24.04
runner: macos-15
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- uses: actions/setup-python@v6
- uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
with:
python-version: '3.11'
- name: Native Windows MSVC (release)
if: runner.os == 'Windows' && matrix.architecture != 'ARM64'
shell: pwsh
run: |
choco install visualstudio2026buildtools --no-progress -y --force --params "--add Microsoft.VisualStudio.Component.VC.Tools.x86.x64 --locale en-US --passive"
$env:PATH = "C:\Program Files (x86)\Microsoft Visual Studio\18\BuildTools\MSBuild\Current\bin;$env:PATH"
$env:PlatformToolset = "v145"
./PCbuild/build.bat --tail-call-interp -c Release -p ${{ matrix.architecture }}
./PCbuild/rt.bat -p ${{ matrix.architecture }} -q --multiprocess 0 --timeout 4500 --verbose2 --verbose3
# No tests (yet):
- name: Emulated Windows Clang (release)
if: runner.os == 'Windows' && matrix.architecture == 'ARM64'
shell: pwsh
run: |
choco install llvm --allow-downgrade --no-progress --version ${{ matrix.llvm }}.1.0
$env:PlatformToolset = "clangcl"
$env:LLVMToolsVersion = "${{ matrix.llvm }}.1.0"
$env:LLVMInstallDir = "C:\Program Files\LLVM"
./PCbuild/build.bat --tail-call-interp -p ${{ matrix.architecture }}
- name: Native macOS (release)
if: runner.os == 'macOS'
- name: Install dependencies
run: |
brew update
brew install llvm@${{ matrix.llvm }}
brew install llvm@${{ env.LLVM_VERSION }}
- name: Build
run: |
export SDKROOT="$(xcrun --show-sdk-path)"
export PATH="/usr/local/opt/llvm@${{ matrix.llvm }}/bin:$PATH"
export PATH="/opt/homebrew/opt/llvm@${{ matrix.llvm }}/bin:$PATH"
CC=clang-20 ./configure --with-tail-call-interp
export PATH="/usr/local/opt/llvm@${{ env.LLVM_VERSION }}/bin:$PATH"
export PATH="/opt/homebrew/opt/llvm@${{ env.LLVM_VERSION }}/bin:$PATH"
CC=clang-${{ env.LLVM_VERSION }} ./configure --with-tail-call-interp
make all --jobs 4
- name: Test
run: |
./python.exe -m test --multiprocess 0 --timeout 4500 --verbose2 --verbose3
- name: Native Linux (debug)
if: runner.os == 'Linux' && matrix.target != 'free-threading'
linux:
name: ${{ matrix.target }}
runs-on: ${{ matrix.runner }}
timeout-minutes: 60
strategy:
fail-fast: false
matrix:
include:
- target: x86_64-unknown-linux-gnu/gcc
runner: ubuntu-24.04
configure_flags: --with-pydebug
- target: x86_64-unknown-linux-gnu/gcc-free-threading
runner: ubuntu-24.04
configure_flags: --disable-gil
- target: aarch64-unknown-linux-gnu/gcc
runner: ubuntu-24.04-arm
configure_flags: --with-pydebug
steps:
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
with:
python-version: '3.11'
- name: Build
run: |
sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" ./llvm.sh ${{ matrix.llvm }}
export PATH="$(llvm-config-${{ matrix.llvm }} --bindir):$PATH"
CC=clang-20 ./configure --with-tail-call-interp --with-pydebug
sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" ./llvm.sh ${{ env.LLVM_VERSION }}
export PATH="$(llvm-config-${{ env.LLVM_VERSION }} --bindir):$PATH"
CC=clang-${{ env.LLVM_VERSION }} ./configure --with-tail-call-interp ${{ matrix.configure_flags }}
make all --jobs 4
./python -m test --multiprocess 0 --timeout 4500 --verbose2 --verbose3
- name: Native Linux with free-threading (release)
if: matrix.target == 'free-threading'
- name: Test
run: |
sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" ./llvm.sh ${{ matrix.llvm }}
export PATH="$(llvm-config-${{ matrix.llvm }} --bindir):$PATH"
CC=clang-20 ./configure --with-tail-call-interp --disable-gil
make all --jobs 4
./python -m test --multiprocess 0 --timeout 4500 --verbose2 --verbose3

4
.github/workflows/verify-ensurepip-wheels.yml vendored
View file

@ -25,10 +25,10 @@ jobs:
runs-on: ubuntu-latest
timeout-minutes: 10
steps:
- uses: actions/checkout@v6
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- uses: actions/setup-python@v6
- uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
with:
python-version: '3'
- name: Compare checksum of bundled wheels to the ones published on PyPI

32
.github/workflows/verify-expat.yml vendored Normal file
View file

@ -0,0 +1,32 @@
name: Verify bundled libexpat
on:
workflow_dispatch:
push:
paths:
- 'Modules/expat/**'
- '.github/workflows/verify-expat.yml'
pull_request:
paths:
- 'Modules/expat/**'
- '.github/workflows/verify-expat.yml'
permissions:
contents: read
concurrency:
group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
cancel-in-progress: true
jobs:
verify:
runs-on: ubuntu-latest
timeout-minutes: 5
steps:
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
persist-credentials: false
- name: Download and verify bundled libexpat files
run: |
./Modules/expat/refresh.sh
git diff --exit-code Modules/expat/

6
.github/zizmor.yml vendored
View file

@ -1,10 +1,6 @@
# Configuration for the zizmor static analysis tool, run via prek in CI
# https://woodruffw.github.io/zizmor/configuration/
# https://docs.zizmor.sh/configuration/
rules:
dangerous-triggers:
ignore:
- documentation-links.yml
unpinned-uses:
config:
policies:
"*": ref-pin

3
.gitignore vendored
View file

@ -5,6 +5,7 @@
*.cover
*.iml
*.o
*.o.tmp
*.lto
*.a
*.so
@ -137,7 +138,7 @@ Tools/unicode/data/
/config.status
/config.status.lineno
/.ccache
/cross-build/
/cross-build*/
/jit_stencils*.h
/platform
/profile-clean-stamp

41
.pre-commit-config.yaml
View file

@ -1,11 +1,11 @@
repos:
- repo: https://github.com/astral-sh/ruff-pre-commit
rev: v0.14.10
rev: e05c5c0818279e5ac248ac9e954431ba58865e61 # frozen: v0.15.7
hooks:
- id: ruff-check
name: Run Ruff (lint) on Apple/
args: [--exit-non-zero-on-fix, --config=Apple/.ruff.toml]
files: ^Apple/
name: Run Ruff (lint) on Platforms/Apple/
args: [--exit-non-zero-on-fix, --config=Platforms/Apple/.ruff.toml]
files: ^Platforms/Apple/
- id: ruff-check
name: Run Ruff (lint) on Doc/
args: [--exit-non-zero-on-fix]
@ -14,6 +14,10 @@ repos:
name: Run Ruff (lint) on Lib/test/
args: [--exit-non-zero-on-fix]
files: ^Lib/test/
- id: ruff-check
name: Run Ruff (lint) on Platforms/WASI/
args: [--exit-non-zero-on-fix, --config=Platforms/WASI/.ruff.toml]
files: ^Platforms/WASI/
- id: ruff-check
name: Run Ruff (lint) on Tools/build/
args: [--exit-non-zero-on-fix, --config=Tools/build/.ruff.toml]
@ -35,13 +39,17 @@ repos:
args: [--exit-non-zero-on-fix, --config=Tools/wasm/.ruff.toml]
files: ^Tools/wasm/
- id: ruff-format
name: Run Ruff (format) on Apple/
args: [--exit-non-zero-on-fix, --config=Apple/.ruff.toml]
files: ^Apple
name: Run Ruff (format) on Platforms/Apple/
args: [--exit-non-zero-on-fix, --config=Platforms/Apple/.ruff.toml]
files: ^Platforms/Apple/
- id: ruff-format
name: Run Ruff (format) on Doc/
args: [--exit-non-zero-on-fix]
files: ^Doc/
- id: ruff-format
name: Run Ruff (format) on Platforms/WASI/
args: [--exit-non-zero-on-fix, --config=Platforms/WASI/.ruff.toml]
files: ^Platforms/WASI/
- id: ruff-format
name: Run Ruff (format) on Tools/build/check_warnings.py
args: [--exit-non-zero-on-fix, --config=Tools/build/.ruff.toml]
@ -52,20 +60,20 @@ repos:
files: ^Tools/wasm/
- repo: https://github.com/psf/black-pre-commit-mirror
rev: 25.12.0
rev: ea488cebbfd88a5f50b8bd95d5c829d0bb76feb8 # frozen: 26.1.0
hooks:
- id: black
name: Run Black on Tools/jit/
files: ^Tools/jit/
- repo: https://github.com/Lucas-C/pre-commit-hooks
rev: v1.5.5
rev: ad1b27d73581aa16cca06fc4a0761fc563ffe8e8 # frozen: v1.5.6
hooks:
- id: remove-tabs
types: [python]
- repo: https://github.com/pre-commit/pre-commit-hooks
rev: v6.0.0
rev: 3e8a8703264a2f4a69428a0aa4dcb512790b2c8c # frozen: v6.0.0
hooks:
- id: check-case-conflict
- id: check-merge-conflict
@ -77,30 +85,33 @@ repos:
exclude: Lib/test/tokenizedata/coding20731.py
- id: end-of-file-fixer
files: '^\.github/CODEOWNERS$'
- id: mixed-line-ending
args: [--fix=auto]
exclude: '^Lib/test/.*data/'
- id: trailing-whitespace
types_or: [c, inc, python, rst, yaml]
- id: trailing-whitespace
files: '^\.github/CODEOWNERS|\.(gram)$'
- repo: https://github.com/python-jsonschema/check-jsonschema
rev: 0.36.0
rev: 9f48a48aa91a6040d749ad68ec70907d907a5a7f # frozen: 0.37.0
hooks:
- id: check-dependabot
- id: check-github-workflows
- id: check-readthedocs
- repo: https://github.com/rhysd/actionlint
rev: v1.7.9
rev: 393031adb9afb225ee52ae2ccd7a5af5525e03e8 # frozen: v1.7.11
hooks:
- id: actionlint
- repo: https://github.com/woodruffw/zizmor-pre-commit
rev: v1.19.0
- repo: https://github.com/zizmorcore/zizmor-pre-commit
rev: b546b77c44c466a54a42af5499dcc0dcc1a3193f # frozen: v1.22.0
hooks:
- id: zizmor
- repo: https://github.com/sphinx-contrib/sphinx-lint
rev: v1.0.2
rev: c883505f64b59c3c5c9375191e4ad9f98e727ccd # frozen: v1.0.2
hooks:
- id: sphinx-lint
args: [--enable=default-role]

3
Doc/.ruff.toml
View file

@ -32,6 +32,9 @@ ignore = [
"E501", # Ignore line length errors (we use auto-formatting)
]
[lint.per-file-ignores]
"tools/check-html-ids.py" = ["I001"] # Unsorted imports
[format]
preview = true
quote-style = "preserve"

15
Doc/Makefile
View file

@ -58,7 +58,7 @@ build:
@if [ -f ../Misc/NEWS ] ; then \
echo "Using existing Misc/NEWS file"; \
cp ../Misc/NEWS build/NEWS; \
elif $(BLURB) help >/dev/null 2>&1 && $(SPHINXBUILD) --version >/dev/null 2>&1; then \
elif $(BLURB) --version && $(SPHINXBUILD) --version ; then \
if [ -d ../Misc/NEWS.d ]; then \
echo "Building NEWS from Misc/NEWS.d with blurb"; \
$(BLURB) merge -f build/NEWS; \
@ -88,6 +88,7 @@ htmlhelp: build
"build/htmlhelp/pydoc.hhp project file."
.PHONY: latex
latex: _ensure-sphinxcontrib-svg2pdfconverter
latex: BUILDER = latex
latex: build
@echo "Build finished; the LaTeX files are in build/latex."
@ -231,7 +232,7 @@ dist-text:
@echo "Build finished and archived!"
.PHONY: dist-pdf
dist-pdf:
dist-pdf: _ensure-sphinxcontrib-svg2pdfconverter
# archive the A4 latex
@echo "Building LaTeX (A4 paper)..."
mkdir -p dist
@ -292,6 +293,10 @@ _ensure-pre-commit:
_ensure-sphinx-autobuild:
$(MAKE) _ensure-package PACKAGE=sphinx-autobuild
.PHONY: _ensure-sphinxcontrib-svg2pdfconverter
_ensure-sphinxcontrib-svg2pdfconverter:
$(MAKE) _ensure-package PACKAGE=sphinxcontrib-svg2pdfconverter
.PHONY: check
check: _ensure-pre-commit
$(VENVDIR)/bin/python3 -m pre_commit run --all-files
@ -336,3 +341,9 @@ autobuild-stable-html:
exit 1;; \
esac
@$(MAKE) autobuild-dev-html
# Collect HTML IDs to a JSON document
.PHONY: html-ids
html-ids:
$(PYTHON) tools/check-html-ids.py collect build/html \
-o build/html/html-ids.json.gz

570
Doc/_static/profiling-sampling-visualization.css Normal file
View file

@ -0,0 +1,570 @@
/**
* Sampling Profiler Visualization - Scoped CSS
*/
.sampling-profiler-viz {
/* Match docs background colors */
--bg-page: #ffffff;
--bg-panel: #ffffff;
--bg-subtle: #f8f8f8;
--bg-code: #f8f8f8;
/* Match docs border style */
--border-color: #e1e4e8;
--border-accent: #3776ab;
/* Match docs text colors */
--text-primary: #0d0d0d;
--text-secondary: #505050;
--text-muted: #6e6e6e;
--text-code: #333333;
/* Accent colors */
--color-python-blue: #306998;
--color-green: #388e3c;
--color-orange: #e65100;
--color-purple: #7b1fa2;
--color-red: #c62828;
--color-teal: #00897b;
--color-yellow: #d4a910;
--color-highlight: #fff9e6;
--radius-lg: 8px;
--radius-md: 6px;
--radius-sm: 4px;
/* Lighter shadows to match docs style */
--shadow-card: 0 1px 3px rgba(0, 0, 0, 0.08);
--shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
--container-height: 520px;
--code-panel-width: 320px;
/* Reset for isolation */
font-family: var(--font-ui);
line-height: 1.5;
font-weight: 400;
color: var(--text-primary);
background-color: var(--bg-page);
font-synthesis: none;
text-rendering: optimizeLegibility;
-webkit-font-smoothing: antialiased;
-moz-osx-font-smoothing: grayscale;
/* Layout */
position: relative;
width: 100%;
max-width: 920px;
height: var(--container-height);
display: grid;
grid-template-columns: var(--code-panel-width) 1fr;
margin: 24px auto;
border-radius: var(--radius-lg);
overflow: hidden;
box-shadow: var(--shadow-card);
border: 1px solid var(--border-color);
background: var(--bg-panel);
/* Prevent any DOM changes inside from affecting page scroll */
contain: strict;
}
.sampling-profiler-viz * {
box-sizing: border-box;
}
/* Code Panel - Left Column */
.sampling-profiler-viz #code-panel {
background: var(--bg-panel);
border-right: 1px solid var(--border-color);
overflow-y: auto;
font-family: var(--font-mono);
font-size: 12px;
line-height: 1.6;
display: flex;
flex-direction: column;
}
.sampling-profiler-viz #code-panel .code-panel-title {
padding: 12px 16px;
font-size: 10px;
font-weight: 600;
color: var(--text-muted);
border-bottom: 1px solid var(--border-color);
background: var(--bg-code);
text-transform: uppercase;
letter-spacing: 1px;
flex-shrink: 0;
}
.sampling-profiler-viz #code-panel .code-container {
margin: 0;
padding: 12px 0;
overflow-x: auto;
flex: 1;
}
.sampling-profiler-viz #code-panel .line {
display: flex;
padding: 1px 0;
min-height: 20px;
transition: background-color 0.1s ease;
}
.sampling-profiler-viz #code-panel .line-number {
color: var(--text-muted);
min-width: 40px;
text-align: right;
padding-right: 12px;
padding-left: 12px;
user-select: none;
flex-shrink: 0;
font-size: 11px;
}
.sampling-profiler-viz #code-panel .line-content {
flex: 1;
color: var(--text-code);
padding-right: 12px;
white-space: pre;
}
.sampling-profiler-viz #code-panel .line.highlighted {
background: var(--color-highlight);
border-left: 3px solid var(--color-yellow);
}
.sampling-profiler-viz #code-panel .line.highlighted .line-number {
color: var(--color-yellow);
padding-left: 9px;
}
.sampling-profiler-viz #code-panel .line.highlighted .line-content {
font-weight: 600;
}
/* Python Syntax Highlighting */
.sampling-profiler-viz #code-panel .keyword {
color: var(--color-red);
font-weight: 600;
}
.sampling-profiler-viz #code-panel .function {
color: var(--color-purple);
font-weight: 600;
}
.sampling-profiler-viz #code-panel .number {
color: var(--color-python-blue);
}
.sampling-profiler-viz #code-panel .string {
color: #032f62;
}
.sampling-profiler-viz #code-panel .comment {
color: #6a737d;
font-style: italic;
}
.sampling-profiler-viz #code-panel .builtin {
color: var(--color-python-blue);
}
/* Visualization Column - Right Side */
.sampling-profiler-viz .viz-column {
display: flex;
flex-direction: column;
background: var(--bg-subtle);
overflow: hidden;
}
/* Stack Section */
.sampling-profiler-viz .stack-section {
padding: 12px 16px;
flex: 1;
min-height: 150px;
overflow-y: auto;
}
.sampling-profiler-viz .stack-section-title {
font-size: 10px;
font-weight: 600;
color: var(--text-muted);
text-transform: uppercase;
letter-spacing: 1px;
margin-bottom: 10px;
}
.sampling-profiler-viz .stack-visualization {
display: flex;
flex-direction: column;
gap: 4px;
min-height: 80px;
}
/* Stack Frames - Vertical Layout */
.sampling-profiler-viz .stack-frame {
position: relative;
width: 100%;
height: 32px;
cursor: pointer;
contain: layout style paint;
opacity: 0;
transform: translateY(-10px);
}
.sampling-profiler-viz .stack-frame.visible {
opacity: 1;
transform: translateY(0);
transition:
opacity 0.3s ease,
transform 0.3s ease;
}
.sampling-profiler-viz .stack-frame-bg {
position: absolute;
inset: 0;
border-radius: var(--radius-sm);
transition: opacity 0.15s;
}
.sampling-profiler-viz .stack-frame-text {
position: absolute;
left: 10px;
top: 50%;
transform: translateY(-50%);
font: 500 11px var(--font-mono);
color: white;
pointer-events: none;
}
.sampling-profiler-viz .stack-frame-flash {
position: absolute;
inset: 0;
background: white;
border-radius: var(--radius-sm);
opacity: 0;
pointer-events: none;
}
.sampling-profiler-viz .stack-frame:hover .stack-frame-bg {
opacity: 0.85;
}
/* Flying frames */
.sampling-profiler-viz .stack-frame.flying {
pointer-events: none;
z-index: 1000;
position: fixed;
top: 0;
left: 0;
width: auto;
height: 32px;
opacity: 1;
}
/* Flying stack clone */
.stack-visualization.flying-clone {
transform-origin: center center;
will-change: transform, opacity;
}
/* Sampling Panel */
.sampling-profiler-viz .sampling-panel {
margin: 0 16px 12px 16px;
background: var(--bg-panel);
border: 1px solid var(--border-color);
border-radius: var(--radius-md);
box-shadow: var(--shadow-sm);
overflow: hidden;
display: flex;
flex-direction: column;
flex: 0 0 auto;
height: 200px;
/* Lock font size to prevent Sphinx responsive scaling */
font-size: 12px;
}
.sampling-profiler-viz .sampling-header {
padding: 8px 10px;
border-bottom: 1px solid var(--border-color);
flex-shrink: 0;
}
.sampling-profiler-viz .sampling-title {
font: 600 10px var(--font-mono);
color: var(--text-primary);
margin: 0 0 3px 0;
}
.sampling-profiler-viz .sampling-stats {
font: 400 9px var(--font-mono);
color: var(--text-secondary);
display: flex;
gap: 12px;
}
.sampling-profiler-viz .sampling-stats .missed {
color: var(--color-red);
}
.sampling-profiler-viz .sampling-bars {
flex: 1;
padding: 10px 12px;
overflow-y: auto;
}
.sampling-profiler-viz .sampling-bar-row {
display: flex;
align-items: center;
height: 22px;
gap: 8px;
}
.sampling-profiler-viz .bar-label {
font: 500 8px var(--font-mono);
color: var(--text-primary);
flex-shrink: 0;
width: 60px;
overflow: hidden;
text-overflow: ellipsis;
}
.sampling-profiler-viz .bar-container {
flex: 1;
height: 12px;
background: var(--border-color);
border-radius: 3px;
position: relative;
overflow: hidden;
}
.sampling-profiler-viz .bar-fill {
height: 100%;
border-radius: 3px;
transition: width 0.2s ease;
min-width: 2px;
}
.sampling-profiler-viz .bar-percent {
font: 500 8px var(--font-mono);
color: var(--text-secondary);
width: 36px;
text-align: right;
flex-shrink: 0;
}
/* Impact effect circle */
.impact-circle {
position: fixed;
width: 30px;
height: 30px;
border-radius: 50%;
background: var(--color-teal);
transform: translate(-50%, -50%);
pointer-events: none;
z-index: 2000;
}
/* Control Panel - Integrated */
.sampling-profiler-viz #control-panel {
display: flex;
align-items: center;
gap: 12px;
padding: 12px 16px;
background: var(--bg-panel);
border-top: 1px solid var(--border-color);
flex-shrink: 0;
flex-wrap: wrap;
}
.sampling-profiler-viz .control-group {
display: flex;
gap: 6px;
align-items: center;
}
.sampling-profiler-viz .control-group label {
font-size: 10px;
color: var(--text-muted);
font-weight: 500;
white-space: nowrap;
}
.sampling-profiler-viz .control-btn {
background: var(--bg-panel);
color: var(--text-primary);
border: 1px solid var(--border-color);
padding: 6px 10px;
border-radius: var(--radius-sm);
cursor: pointer;
transition: all 0.15s ease;
font-family: var(--font-mono);
font-size: 11px;
font-weight: 500;
display: flex;
align-items: center;
gap: 4px;
}
.sampling-profiler-viz .control-btn:hover {
background: var(--bg-subtle);
border-color: var(--text-muted);
}
.sampling-profiler-viz .control-btn:active {
transform: scale(0.98);
}
.sampling-profiler-viz .control-btn.active {
background: var(--color-python-blue);
color: white;
border-color: var(--color-python-blue);
}
.sampling-profiler-viz .control-btn.active:hover {
background: #2f6493;
}
/* Timeline Scrubber */
.sampling-profiler-viz .timeline-scrubber {
flex: 1;
display: flex;
align-items: center;
gap: 8px;
min-width: 160px;
}
.sampling-profiler-viz #timeline-scrubber {
flex: 1;
height: 5px;
border-radius: 3px;
background: var(--border-color);
outline: none;
appearance: none;
-webkit-appearance: none;
cursor: pointer;
min-width: 60px;
}
.sampling-profiler-viz #timeline-scrubber::-webkit-slider-thumb {
-webkit-appearance: none;
width: 14px;
height: 14px;
border-radius: 50%;
background: var(--color-python-blue);
cursor: pointer;
transition: transform 0.15s;
box-shadow: 0 2px 6px rgba(0, 0, 0, 0.2);
}
.sampling-profiler-viz #timeline-scrubber::-webkit-slider-thumb:hover {
transform: scale(1.15);
}
.sampling-profiler-viz #timeline-scrubber::-moz-range-thumb {
width: 14px;
height: 14px;
border-radius: 50%;
background: var(--color-python-blue);
cursor: pointer;
border: none;
box-shadow: 0 2px 6px rgba(0, 0, 0, 0.2);
}
.sampling-profiler-viz #time-display {
font: 500 10px var(--font-mono);
color: var(--text-secondary);
min-width: 90px;
text-align: right;
font-variant-numeric: tabular-nums;
}
/* Sample Interval Slider */
.sampling-profiler-viz #sample-interval {
width: 80px;
height: 4px;
border-radius: 2px;
background: var(--border-color);
outline: none;
appearance: none;
-webkit-appearance: none;
cursor: pointer;
flex-shrink: 0;
}
.sampling-profiler-viz #sample-interval::-webkit-slider-thumb {
-webkit-appearance: none;
width: 12px;
height: 12px;
border-radius: 50%;
background: var(--color-teal);
cursor: pointer;
transition: transform 0.15s;
box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}
.sampling-profiler-viz #sample-interval::-webkit-slider-thumb:hover {
transform: scale(1.15);
}
.sampling-profiler-viz #sample-interval::-moz-range-thumb {
width: 12px;
height: 12px;
border-radius: 50%;
background: var(--color-teal);
cursor: pointer;
border: none;
}
.sampling-profiler-viz #interval-display {
font: 500 9px var(--font-mono);
color: var(--text-secondary);
min-width: 40px;
font-variant-numeric: tabular-nums;
}
/* Flash overlay */
.sampling-profiler-viz .flash-overlay {
position: absolute;
inset: 0;
background: white;
pointer-events: none;
opacity: 0;
}
/* Performance optimizations */
.sampling-profiler-viz .stack-frame,
.sampling-profiler-viz .flying-frame,
.sampling-profiler-viz .sampling-bar-row {
will-change: transform, opacity;
contain: layout style paint;
}
/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
.sampling-profiler-viz .stack-frame,
.sampling-profiler-viz .flying-frame,
.sampling-profiler-viz .sampling-bar-row,
.impact-circle {
animation-duration: 0.01ms !important;
transition-duration: 0.01ms !important;
}
}
/* Responsive adjustments for narrower viewports */
@media (max-width: 800px) {
.sampling-profiler-viz {
grid-template-columns: 280px 1fr;
--container-height: 550px;
}
.sampling-profiler-viz #code-panel {
font-size: 11px;
}
.sampling-profiler-viz .control-btn {
padding: 5px 8px;
font-size: 10px;
}
}

1163
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2
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@ -9,7 +9,7 @@ stability. In order to maintain this reputation, the developers would like to
know of any deficiencies you find in Python.
It can be sometimes faster to fix bugs yourself and contribute patches to
Python as it streamlines the process and involves less people. Learn how to
Python as it streamlines the process and involves fewer people. Learn how to
:ref:`contribute <contributing-to-python>`.
Documentation bugs

12
Doc/c-api/allocation.rst
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@ -2,7 +2,7 @@
.. _allocating-objects:
Allocating Objects on the Heap
Allocating objects on the heap
==============================
@ -153,10 +153,12 @@ Allocating Objects on the Heap
To allocate and create extension modules.
Deprecated aliases
^^^^^^^^^^^^^^^^^^
Soft-deprecated aliases
^^^^^^^^^^^^^^^^^^^^^^^
These are :term:`soft deprecated` aliases to existing functions and macros.
.. soft-deprecated:: 3.15
These are aliases to existing functions and macros.
They exist solely for backwards compatibility.
@ -164,7 +166,7 @@ They exist solely for backwards compatibility.
:widths: auto
:header-rows: 1
* * Deprecated alias
* * Soft-deprecated alias
* Function
* * .. c:macro:: PyObject_NEW(type, typeobj)
* :c:macro:`PyObject_New`

22
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@ -516,6 +516,28 @@ API Functions
}
.. c:function:: int PyArg_ParseArray(PyObject *const *args, Py_ssize_t nargs, const char *format, ...)
Parse the parameters of a function that takes only array parameters into
local variables (that is, a function using the :c:macro:`METH_FASTCALL`
calling convention).
Returns true on success; on failure, it returns false and raises the
appropriate exception.
.. versionadded:: 3.15
.. c:function:: int PyArg_ParseArrayAndKeywords(PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames, const char *format, const char * const *kwlist, ...)
Parse the parameters of a function that takes both array and keyword
parameters into local variables (that is, a function using the
:c:macro:`METH_FASTCALL` ``|`` :c:macro:`METH_KEYWORDS` calling convention).
Returns true on success; on failure, it returns false and raises the
appropriate exception.
.. versionadded:: 3.15
.. c:function:: int PyArg_UnpackTuple(PyObject *args, const char *name, Py_ssize_t min, Py_ssize_t max, ...)
A simpler form of parameter retrieval which does not use a format string to

14
Doc/c-api/buffer.rst
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@ -10,11 +10,6 @@
Buffer Protocol
---------------
.. sectionauthor:: Greg Stein <gstein@lyra.org>
.. sectionauthor:: Benjamin Peterson
.. sectionauthor:: Stefan Krah
Certain objects available in Python wrap access to an underlying memory
array or *buffer*. Such objects include the built-in :class:`bytes` and
:class:`bytearray`, and some extension types like :class:`array.array`.
@ -263,7 +258,9 @@ readonly, format
.. c:macro:: PyBUF_WRITEABLE
This is a :term:`soft deprecated` alias to :c:macro:`PyBUF_WRITABLE`.
This is an alias to :c:macro:`PyBUF_WRITABLE`.
.. soft-deprecated:: 3.13
.. c:macro:: PyBUF_FORMAT
@ -505,10 +502,11 @@ Buffer-related functions
*indices* must point to an array of ``view->ndim`` indices.
.. c:function:: int PyBuffer_FromContiguous(const Py_buffer *view, const void *buf, Py_ssize_t len, char fort)
.. c:function:: int PyBuffer_FromContiguous(const Py_buffer *view, const void *buf, Py_ssize_t len, char order)
Copy contiguous *len* bytes from *buf* to *view*.
*fort* can be ``'C'`` or ``'F'`` (for C-style or Fortran-style ordering).
*order* can be ``'C'`` or ``'F'`` or ``'A'`` (for C-style or Fortran-style
ordering or either one).
``0`` is returned on success, ``-1`` on error.

14
Doc/c-api/bytearray.rst
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@ -44,6 +44,10 @@ Direct API functions
On failure, return ``NULL`` with an exception set.
.. note::
If the object implements the buffer protocol, then the buffer
must not be mutated while the bytearray object is being created.
.. c:function:: PyObject* PyByteArray_FromStringAndSize(const char *string, Py_ssize_t len)
@ -58,6 +62,10 @@ Direct API functions
On failure, return ``NULL`` with an exception set.
.. note::
If the object implements the buffer protocol, then the buffer
must not be mutated while the bytearray object is being created.
.. c:function:: Py_ssize_t PyByteArray_Size(PyObject *bytearray)
@ -70,6 +78,9 @@ Direct API functions
``NULL`` pointer. The returned array always has an extra
null byte appended.
.. note::
It is not thread-safe to mutate the bytearray object while using the returned char array.
.. c:function:: int PyByteArray_Resize(PyObject *bytearray, Py_ssize_t len)
@ -89,6 +100,9 @@ These macros trade safety for speed and they don't check pointers.
Similar to :c:func:`PyByteArray_AsString`, but without error checking.
.. note::
It is not thread-safe to mutate the bytearray object while using the returned char array.
.. c:function:: Py_ssize_t PyByteArray_GET_SIZE(PyObject *bytearray)

29
Doc/c-api/bytes.rst
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@ -47,9 +47,9 @@ called with a non-bytes parameter.
*len* on success, and ``NULL`` on failure. If *v* is ``NULL``, the contents of
the bytes object are uninitialized.
.. deprecated:: 3.15
``PyBytes_FromStringAndSize(NULL, len)`` is :term:`soft deprecated`,
use the :c:type:`PyBytesWriter` API instead.
.. soft-deprecated:: 3.15
Use the :c:type:`PyBytesWriter` API instead of
``PyBytes_FromStringAndSize(NULL, len)``.
.. c:function:: PyObject* PyBytes_FromFormat(const char *format, ...)
@ -127,6 +127,10 @@ called with a non-bytes parameter.
Return the bytes representation of object *o* that implements the buffer
protocol.
.. note::
If the object implements the buffer protocol, then the buffer
must not be mutated while the bytes object is being created.
.. c:function:: Py_ssize_t PyBytes_Size(PyObject *o)
@ -185,6 +189,9 @@ called with a non-bytes parameter.
created, the old reference to *bytes* will still be discarded and the value
of *\*bytes* will be set to ``NULL``; the appropriate exception will be set.
.. note::
If *newpart* implements the buffer protocol, then the buffer
must not be mutated while the new bytes object is being created.
.. c:function:: void PyBytes_ConcatAndDel(PyObject **bytes, PyObject *newpart)
@ -192,6 +199,10 @@ called with a non-bytes parameter.
appended to *bytes*. This version releases the :term:`strong reference`
to *newpart* (i.e. decrements its reference count).
.. note::
If *newpart* implements the buffer protocol, then the buffer
must not be mutated while the new bytes object is being created.
.. c:function:: PyObject* PyBytes_Join(PyObject *sep, PyObject *iterable)
@ -210,6 +221,9 @@ called with a non-bytes parameter.
.. versionadded:: 3.14
.. note::
If *iterable* objects implement the buffer protocol, then the buffers
must not be mutated while the new bytes object is being created.
.. c:function:: int _PyBytes_Resize(PyObject **bytes, Py_ssize_t newsize)
@ -224,9 +238,8 @@ called with a non-bytes parameter.
*\*bytes* is set to ``NULL``, :exc:`MemoryError` is set, and ``-1`` is
returned.
.. deprecated:: 3.15
The function is :term:`soft deprecated`,
use the :c:type:`PyBytesWriter` API instead.
.. soft-deprecated:: 3.15
Use the :c:type:`PyBytesWriter` API instead.
.. c:function:: PyObject *PyBytes_Repr(PyObject *bytes, int smartquotes)
@ -371,6 +384,8 @@ Getters
Get the writer size.
The function cannot fail.
.. c:function:: void* PyBytesWriter_GetData(PyBytesWriter *writer)
Get the writer data: start of the internal buffer.
@ -378,6 +393,8 @@ Getters
The pointer is valid until :c:func:`PyBytesWriter_Finish` or
:c:func:`PyBytesWriter_Discard` is called on *writer*.
The function cannot fail.
Low-level API
^^^^^^^^^^^^^

6
Doc/c-api/code.rst
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@ -7,8 +7,6 @@
Code Objects
------------
.. sectionauthor:: Jeffrey Yasskin <jyasskin@gmail.com>
Code objects are a low-level detail of the CPython implementation.
Each one represents a chunk of executable code that hasn't yet been
bound into a function.
@ -214,7 +212,7 @@ bound into a function.
.. c:function:: PyObject *PyCode_Optimize(PyObject *code, PyObject *consts, PyObject *names, PyObject *lnotab_obj)
This is a :term:`soft deprecated` function that does nothing.
This is a function that does nothing.
Prior to Python 3.10, this function would perform basic optimizations to a
code object.
@ -222,6 +220,8 @@ bound into a function.
.. versionchanged:: 3.10
This function now does nothing.
.. soft-deprecated:: 3.13
.. _c_codeobject_flags:

9
Doc/c-api/datetime.rst
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@ -30,6 +30,10 @@ macros.
This is not compatible with subinterpreters.
.. versionchanged:: 3.15
This macro is now thread safe.
.. c:type:: PyDateTime_CAPI
Structure containing the fields for the datetime C API.
@ -44,6 +48,11 @@ macros.
This variable is only available once :c:macro:`PyDateTime_IMPORT` succeeds.
.. versionchanged:: 3.15
This variable should not be accessed directly as direct access is not thread-safe.
Use :c:func:`PyDateTime_IMPORT` instead.
.. c:type:: PyDateTime_Date
This subtype of :c:type:`PyObject` represents a Python date object.

93
Doc/c-api/descriptor.rst
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@ -8,13 +8,31 @@ Descriptor Objects
"Descriptors" are objects that describe some attribute of an object. They are
found in the dictionary of type objects.
.. XXX document these!
.. c:function:: PyObject* PyDescr_NewGetSet(PyTypeObject *type, struct PyGetSetDef *getset)
Create a new get-set descriptor for extension type *type* from the
:c:type:`PyGetSetDef` structure *getset*.
.. c:function:: PyObject* PyDescr_NewMember(PyTypeObject *type, struct PyMemberDef *meth)
Get-set descriptors expose attributes implemented by C getter and setter
functions rather than stored directly in the instance. This is the same kind
of descriptor created for entries in :c:member:`~PyTypeObject.tp_getset`, and
it appears in Python as a :class:`types.GetSetDescriptorType` object.
On success, return a :term:`strong reference` to the descriptor. Return
``NULL`` with an exception set on failure.
.. c:function:: PyObject* PyDescr_NewMember(PyTypeObject *type, struct PyMemberDef *member)
Create a new member descriptor for extension type *type* from the
:c:type:`PyMemberDef` structure *member*.
Member descriptors expose fields in the type's C struct as Python
attributes. This is the same kind of descriptor created for entries in
:c:member:`~PyTypeObject.tp_members`, and it appears in Python as a
:class:`types.MemberDescriptorType` object.
On success, return a :term:`strong reference` to the descriptor. Return
``NULL`` with an exception set on failure.
.. c:var:: PyTypeObject PyMemberDescr_Type
@ -30,22 +48,53 @@ found in the dictionary of type objects.
The type object for get/set descriptor objects created from
:c:type:`PyGetSetDef` structures. These descriptors implement attributes
whose value is computed by C getter and setter functions, and are used
for many built-in type attributes.
for many built-in type attributes. They correspond to
:class:`types.GetSetDescriptorType` objects in Python.
.. c:function:: PyObject* PyDescr_NewMethod(PyTypeObject *type, struct PyMethodDef *meth)
Create a new method descriptor for extension type *type* from the
:c:type:`PyMethodDef` structure *meth*.
Method descriptors expose C functions as methods on a type. This is the same
kind of descriptor created for entries in
:c:member:`~PyTypeObject.tp_methods`, and it appears in Python as a
:class:`types.MethodDescriptorType` object.
On success, return a :term:`strong reference` to the descriptor. Return
``NULL`` with an exception set on failure.
.. c:var:: PyTypeObject PyMethodDescr_Type
The type object for method descriptor objects created from
:c:type:`PyMethodDef` structures. These descriptors expose C functions as
methods on a type, and correspond to :class:`types.MemberDescriptorType`
methods on a type, and correspond to :class:`types.MethodDescriptorType`
objects in Python.
.. c:function:: PyObject* PyDescr_NewWrapper(PyTypeObject *type, struct wrapperbase *wrapper, void *wrapped)
.. c:struct:: wrapperbase
Describes a slot wrapper used by :c:func:`PyDescr_NewWrapper`.
Each ``wrapperbase`` record stores the Python-visible name and metadata for a
special method implemented by a type slot, together with the wrapper
function used to adapt that slot to Python's calling convention.
.. c:function:: PyObject* PyDescr_NewWrapper(PyTypeObject *type, struct wrapperbase *base, void *wrapped)
Create a new wrapper descriptor for extension type *type* from the
:c:struct:`wrapperbase` structure *base* and the wrapped slot function
pointer
*wrapped*.
Wrapper descriptors expose special methods implemented by type slots. This
is the same kind of descriptor that CPython creates for slot-based special
methods such as ``__repr__`` or ``__add__``, and it appears in Python as a
:class:`types.WrapperDescriptorType` object.
On success, return a :term:`strong reference` to the descriptor. Return
``NULL`` with an exception set on failure.
.. c:var:: PyTypeObject PyWrapperDescr_Type
@ -58,6 +107,16 @@ found in the dictionary of type objects.
.. c:function:: PyObject* PyDescr_NewClassMethod(PyTypeObject *type, PyMethodDef *method)
Create a new class method descriptor for extension type *type* from the
:c:type:`PyMethodDef` structure *method*.
Class method descriptors expose C methods that receive the class rather than
an instance when accessed. This is the same kind of descriptor created for
``METH_CLASS`` entries in :c:member:`~PyTypeObject.tp_methods`, and it
appears in Python as a :class:`types.ClassMethodDescriptorType` object.
On success, return a :term:`strong reference` to the descriptor. Return
``NULL`` with an exception set on failure.
.. c:function:: int PyDescr_IsData(PyObject *descr)
@ -66,12 +125,22 @@ found in the dictionary of type objects.
no error checking.
.. c:function:: PyObject* PyWrapper_New(PyObject *, PyObject *)
.. c:function:: PyObject* PyWrapper_New(PyObject *d, PyObject *self)
Create a new bound wrapper object from the wrapper descriptor *d* and the
instance *self*.
This is the bound form of a wrapper descriptor created by
:c:func:`PyDescr_NewWrapper`. CPython creates these objects when a slot
wrapper is accessed through an instance, and they appear in Python as
:class:`types.MethodWrapperType` objects.
On success, return a :term:`strong reference` to the wrapper object. Return
``NULL`` with an exception set on failure.
.. c:macro:: PyDescr_COMMON
This is a :term:`soft deprecated` macro including the common fields for a
This is a macro including the common fields for a
descriptor object.
This was included in Python's C API by mistake; do not use it in extensions.
@ -79,6 +148,8 @@ found in the dictionary of type objects.
descriptor protocol (:c:member:`~PyTypeObject.tp_descr_get` and
:c:member:`~PyTypeObject.tp_descr_set`).
.. soft-deprecated:: 3.15
Built-in descriptors
^^^^^^^^^^^^^^^^^^^^
@ -104,9 +175,9 @@ Built-in descriptors
.. c:var:: PyTypeObject PyClassMethodDescr_Type
The type object for C-level class method descriptor objects.
This is the type of the descriptors created for :func:`classmethod` defined in
C extension types, and is the same object as :class:`classmethod`
in Python.
This is the type of the descriptors created for :func:`classmethod` defined
in C extension types, and corresponds to
:class:`types.ClassMethodDescriptorType` objects in Python.
.. c:function:: PyObject *PyClassMethod_New(PyObject *callable)

222
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@ -2,7 +2,7 @@
.. _dictobjects:
Dictionary Objects
Dictionary objects
------------------
.. index:: pair: object; dictionary
@ -42,6 +42,12 @@ Dictionary Objects
enforces read-only behavior. This is normally used to create a view to
prevent modification of the dictionary for non-dynamic class types.
The first argument can be a :class:`dict`, a :class:`frozendict`, or a
mapping.
.. versionchanged:: 3.15
Also accept :class:`frozendict`.
.. c:var:: PyTypeObject PyDictProxy_Type
@ -58,6 +64,9 @@ Dictionary Objects
Empty an existing dictionary of all key-value pairs.
Do nothing if the argument is not a :class:`dict` or a :class:`!dict`
subclass.
.. c:function:: int PyDict_Contains(PyObject *p, PyObject *key)
@ -65,6 +74,16 @@ Dictionary Objects
*key*, return ``1``, otherwise return ``0``. On error, return ``-1``.
This is equivalent to the Python expression ``key in p``.
The first argument can be a :class:`dict` or a :class:`frozendict`.
.. note::
The operation is atomic on :term:`free threading <free-threaded build>`
when *key* is :class:`str`, :class:`int`, :class:`float`, :class:`bool` or :class:`bytes`.
.. versionchanged:: 3.15
Also accept :class:`frozendict`.
.. c:function:: int PyDict_ContainsString(PyObject *p, const char *key)
@ -72,14 +91,18 @@ Dictionary Objects
:c:expr:`const char*` UTF-8 encoded bytes string, rather than a
:c:expr:`PyObject*`.
The first argument can be a :class:`dict` or a :class:`frozendict`.
.. versionadded:: 3.13
.. versionchanged:: 3.15
Also accept :class:`frozendict`.
.. c:function:: PyObject* PyDict_Copy(PyObject *p)
Return a new dictionary that contains the same key-value pairs as *p*.
.. c:function:: int PyDict_SetItem(PyObject *p, PyObject *key, PyObject *val)
Insert *val* into the dictionary *p* with a key of *key*. *key* must be
@ -87,6 +110,11 @@ Dictionary Objects
``0`` on success or ``-1`` on failure. This function *does not* steal a
reference to *val*.
.. note::
The operation is atomic on :term:`free threading <free-threaded build>`
when *key* is :class:`str`, :class:`int`, :class:`float`, :class:`bool` or :class:`bytes`.
.. c:function:: int PyDict_SetItemString(PyObject *p, const char *key, PyObject *val)
@ -102,6 +130,11 @@ Dictionary Objects
If *key* is not in the dictionary, :exc:`KeyError` is raised.
Return ``0`` on success or ``-1`` on failure.
.. note::
The operation is atomic on :term:`free threading <free-threaded build>`
when *key* is :class:`str`, :class:`int`, :class:`float`, :class:`bool` or :class:`bytes`.
.. c:function:: int PyDict_DelItemString(PyObject *p, const char *key)
@ -120,8 +153,18 @@ Dictionary Objects
* If the key is missing, set *\*result* to ``NULL`` and return ``0``.
* On error, raise an exception and return ``-1``.
The first argument can be a :class:`dict` or a :class:`frozendict`.
.. note::
The operation is atomic on :term:`free threading <free-threaded build>`
when *key* is :class:`str`, :class:`int`, :class:`float`, :class:`bool` or :class:`bytes`.
.. versionadded:: 3.13
.. versionchanged:: 3.15
Also accept :class:`frozendict`.
See also the :c:func:`PyObject_GetItem` function.
@ -131,16 +174,28 @@ Dictionary Objects
has a key *key*. Return ``NULL`` if the key *key* is missing *without*
setting an exception.
The first argument can be a :class:`dict` or a :class:`frozendict`.
.. note::
Exceptions that occur while this calls :meth:`~object.__hash__` and
:meth:`~object.__eq__` methods are silently ignored.
Prefer the :c:func:`PyDict_GetItemWithError` function instead.
.. note::
In the :term:`free-threaded build`, the returned
:term:`borrowed reference` may become invalid if another thread modifies
the dictionary concurrently. Prefer :c:func:`PyDict_GetItemRef`, which
returns a :term:`strong reference`.
.. versionchanged:: 3.10
Calling this API without an :term:`attached thread state` had been allowed for historical
reason. It is no longer allowed.
.. versionchanged:: 3.15
Also accept :class:`frozendict`.
.. c:function:: PyObject* PyDict_GetItemWithError(PyObject *p, PyObject *key)
@ -149,6 +204,16 @@ Dictionary Objects
occurred. Return ``NULL`` **without** an exception set if the key
wasn't present.
.. note::
In the :term:`free-threaded build`, the returned
:term:`borrowed reference` may become invalid if another thread modifies
the dictionary concurrently. Prefer :c:func:`PyDict_GetItemRef`, which
returns a :term:`strong reference`.
.. versionchanged:: 3.15
Also accept :class:`frozendict`.
.. c:function:: PyObject* PyDict_GetItemString(PyObject *p, const char *key)
@ -164,6 +229,16 @@ Dictionary Objects
Prefer using the :c:func:`PyDict_GetItemWithError` function with your own
:c:func:`PyUnicode_FromString` *key* instead.
.. note::
In the :term:`free-threaded build`, the returned
:term:`borrowed reference` may become invalid if another thread modifies
the dictionary concurrently. Prefer :c:func:`PyDict_GetItemStringRef`,
which returns a :term:`strong reference`.
.. versionchanged:: 3.15
Also accept :class:`frozendict`.
.. c:function:: int PyDict_GetItemStringRef(PyObject *p, const char *key, PyObject **result)
@ -173,6 +248,9 @@ Dictionary Objects
.. versionadded:: 3.13
.. versionchanged:: 3.15
Also accept :class:`frozendict`.
.. c:function:: PyObject* PyDict_SetDefault(PyObject *p, PyObject *key, PyObject *defaultobj)
@ -184,6 +262,14 @@ Dictionary Objects
.. versionadded:: 3.4
.. note::
In the :term:`free-threaded build`, the returned
:term:`borrowed reference` may become invalid if another thread modifies
the dictionary concurrently. Prefer :c:func:`PyDict_SetDefaultRef`,
which returns a :term:`strong reference`.
.. c:function:: int PyDict_SetDefaultRef(PyObject *p, PyObject *key, PyObject *default_value, PyObject **result)
@ -203,6 +289,11 @@ Dictionary Objects
These may refer to the same object: in that case you hold two separate
references to it.
.. note::
The operation is atomic on :term:`free threading <free-threaded build>`
when *key* is :class:`str`, :class:`int`, :class:`float`, :class:`bool` or :class:`bytes`.
.. versionadded:: 3.13
@ -220,6 +311,11 @@ Dictionary Objects
Similar to :meth:`dict.pop`, but without the default value and
not raising :exc:`KeyError` if the key is missing.
.. note::
The operation is atomic on :term:`free threading <free-threaded build>`
when *key* is :class:`str`, :class:`int`, :class:`float`, :class:`bool` or :class:`bytes`.
.. versionadded:: 3.13
@ -236,17 +332,32 @@ Dictionary Objects
Return a :c:type:`PyListObject` containing all the items from the dictionary.
The first argument can be a :class:`dict` or a :class:`frozendict`.
.. versionchanged:: 3.15
Also accept :class:`frozendict`.
.. c:function:: PyObject* PyDict_Keys(PyObject *p)
Return a :c:type:`PyListObject` containing all the keys from the dictionary.
The first argument can be a :class:`dict` or a :class:`frozendict`.
.. versionchanged:: 3.15
Also accept :class:`frozendict`.
.. c:function:: PyObject* PyDict_Values(PyObject *p)
Return a :c:type:`PyListObject` containing all the values from the dictionary
*p*.
The first argument can be a :class:`dict` or a :class:`frozendict`.
.. versionchanged:: 3.15
Also accept :class:`frozendict`.
.. c:function:: Py_ssize_t PyDict_Size(PyObject *p)
@ -255,11 +366,19 @@ Dictionary Objects
Return the number of items in the dictionary. This is equivalent to
``len(p)`` on a dictionary.
The argument can be a :class:`dict` or a :class:`frozendict`.
.. versionchanged:: 3.15
Also accept :class:`frozendict`.
.. c:function:: Py_ssize_t PyDict_GET_SIZE(PyObject *p)
Similar to :c:func:`PyDict_Size`, but without error checking.
.. versionchanged:: 3.15
Also accept :class:`frozendict`.
.. c:function:: int PyDict_Next(PyObject *p, Py_ssize_t *ppos, PyObject **pkey, PyObject **pvalue)
@ -274,6 +393,8 @@ Dictionary Objects
value represents offsets within the internal dictionary structure, and
since the structure is sparse, the offsets are not consecutive.
The first argument can be a :class:`dict` or a :class:`frozendict`.
For example::
PyObject *key, *value;
@ -307,7 +428,7 @@ Dictionary Objects
}
The function is not thread-safe in the :term:`free-threaded <free threading>`
build without external synchronization. You can use
build without external synchronization for a mutable :class:`dict`. You can use
:c:macro:`Py_BEGIN_CRITICAL_SECTION` to lock the dictionary while iterating
over it::
@ -317,6 +438,8 @@ Dictionary Objects
}
Py_END_CRITICAL_SECTION();
The function is thread-safe on a :class:`frozendict`.
.. note::
On the free-threaded build, this function can be used safely inside a
@ -327,6 +450,9 @@ Dictionary Objects
:term:`strong reference <strong reference>` (for example, using
:c:func:`Py_NewRef`).
.. versionchanged:: 3.15
Also accept :class:`frozendict`.
.. c:function:: int PyDict_Merge(PyObject *a, PyObject *b, int override)
Iterate over mapping object *b* adding key-value pairs to dictionary *a*.
@ -336,6 +462,13 @@ Dictionary Objects
only be added if there is not a matching key in *a*. Return ``0`` on
success or ``-1`` if an exception was raised.
.. note::
In the :term:`free-threaded build`, when *b* is a
:class:`dict` (with the standard iterator), both *a* and *b* are locked
for the duration of the operation. When *b* is a non-dict mapping, only
*a* is locked; *b* may be concurrently modified by another thread.
.. c:function:: int PyDict_Update(PyObject *a, PyObject *b)
@ -345,6 +478,13 @@ Dictionary Objects
argument has no "keys" attribute. Return ``0`` on success or ``-1`` if an
exception was raised.
.. note::
In the :term:`free-threaded build`, when *b* is a
:class:`dict` (with the standard iterator), both *a* and *b* are locked
for the duration of the operation. When *b* is a non-dict mapping, only
*a* is locked; *b* may be concurrently modified by another thread.
.. c:function:: int PyDict_MergeFromSeq2(PyObject *a, PyObject *seq2, int override)
@ -360,6 +500,13 @@ Dictionary Objects
if override or key not in a:
a[key] = value
.. note::
In the :term:`free-threaded <free threading>` build, only *a* is locked.
The iteration over *seq2* is not synchronized; *seq2* may be concurrently
modified by another thread.
.. c:function:: int PyDict_AddWatcher(PyDict_WatchCallback callback)
Register *callback* as a dictionary watcher. Return a non-negative integer
@ -367,6 +514,13 @@ Dictionary Objects
of error (e.g. no more watcher IDs available), return ``-1`` and set an
exception.
.. note::
This function is not internally synchronized. In the
:term:`free-threaded <free threading>` build, callers should ensure no
concurrent calls to :c:func:`PyDict_AddWatcher` or
:c:func:`PyDict_ClearWatcher` are in progress.
.. versionadded:: 3.12
.. c:function:: int PyDict_ClearWatcher(int watcher_id)
@ -375,6 +529,13 @@ Dictionary Objects
:c:func:`PyDict_AddWatcher`. Return ``0`` on success, ``-1`` on error (e.g.
if the given *watcher_id* was never registered.)
.. note::
This function is not internally synchronized. In the
:term:`free-threaded <free threading>` build, callers should ensure no
concurrent calls to :c:func:`PyDict_AddWatcher` or
:c:func:`PyDict_ClearWatcher` are in progress.
.. versionadded:: 3.12
.. c:function:: int PyDict_Watch(int watcher_id, PyObject *dict)
@ -444,7 +605,7 @@ Dictionary Objects
.. versionadded:: 3.12
Dictionary View Objects
Dictionary view objects
^^^^^^^^^^^^^^^^^^^^^^^
.. c:function:: int PyDictViewSet_Check(PyObject *op)
@ -490,7 +651,58 @@ Dictionary View Objects
always succeeds.
Ordered Dictionaries
Frozen dictionary objects
^^^^^^^^^^^^^^^^^^^^^^^^^
.. versionadded:: 3.15
.. c:var:: PyTypeObject PyFrozenDict_Type
This instance of :c:type:`PyTypeObject` represents the Python frozen
dictionary type.
This is the same object as :class:`frozendict` in the Python layer.
.. c:function:: int PyAnyDict_Check(PyObject *p)
Return true if *p* is a :class:`dict` object, a :class:`frozendict` object,
or an instance of a subtype of the :class:`!dict` or :class:`!frozendict`
type.
This function always succeeds.
.. c:function:: int PyAnyDict_CheckExact(PyObject *p)
Return true if *p* is a :class:`dict` object or a :class:`frozendict` object,
but not an instance of a subtype of the :class:`!dict` or
:class:`!frozendict` type.
This function always succeeds.
.. c:function:: int PyFrozenDict_Check(PyObject *p)
Return true if *p* is a :class:`frozendict` object or an instance of a
subtype of the :class:`!frozendict` type.
This function always succeeds.
.. c:function:: int PyFrozenDict_CheckExact(PyObject *p)
Return true if *p* is a :class:`frozendict` object, but not an instance of a
subtype of the :class:`!frozendict` type.
This function always succeeds.
.. c:function:: PyObject* PyFrozenDict_New(PyObject *iterable)
Return a new :class:`frozendict` from an iterable, or ``NULL`` on failure
with an exception set.
Create an empty dictionary if *iterable* is ``NULL``.
Ordered dictionaries
^^^^^^^^^^^^^^^^^^^^
Python's C API provides interface for :class:`collections.OrderedDict` from C.

63
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@ -673,28 +673,51 @@ Signal Handling
single: SIGINT (C macro)
single: KeyboardInterrupt (built-in exception)
This function interacts with Python's signal handling.
Handle external interruptions, such as signals or activating a debugger,
whose processing has been delayed until it is safe
to run Python code and/or raise exceptions.
If the function is called from the main thread and under the main Python
interpreter, it checks whether a signal has been sent to the processes
and if so, invokes the corresponding signal handler. If the :mod:`signal`
module is supported, this can invoke a signal handler written in Python.
For example, pressing :kbd:`Ctrl-C` causes a terminal to send the
:py:data:`signal.SIGINT` signal.
This function executes the corresponding Python signal handler, which,
by default, raises the :exc:`KeyboardInterrupt` exception.
The function attempts to handle all pending signals, and then returns ``0``.
However, if a Python signal handler raises an exception, the error
indicator is set and the function returns ``-1`` immediately (such that
other pending signals may not have been handled yet: they will be on the
next :c:func:`PyErr_CheckSignals()` invocation).
:c:func:`!PyErr_CheckSignals` should be called by long-running C code
frequently enough so that the response appears immediate to humans.
If the function is called from a non-main thread, or under a non-main
Python interpreter, it does nothing and returns ``0``.
Handlers invoked by this function currently include:
This function can be called by long-running C code that wants to
be interruptible by user requests (such as by pressing Ctrl-C).
- Signal handlers, including Python functions registered using
the :mod:`signal` module.
.. note::
The default Python signal handler for :c:macro:`!SIGINT` raises the
:exc:`KeyboardInterrupt` exception.
Signal handlers are only run in the main thread of the main interpreter.
(This is where the function got the name: originally, signals
were the only way to interrupt the interpreter.)
- Running the garbage collector, if necessary.
- Executing a pending :ref:`remote debugger <remote-debugging>` script.
- Raise the exception set by :c:func:`PyThreadState_SetAsyncExc`.
If any handler raises an exception, immediately return ``-1`` with that
exception set.
Any remaining interruptions are left to be processed on the next
:c:func:`PyErr_CheckSignals()` invocation, if appropriate.
If all handlers finish successfully, or there are no handlers to run,
return ``0``.
.. versionchanged:: 3.12
This function may now invoke the garbage collector.
.. versionchanged:: 3.14
This function may now execute a remote debugger script, if remote
debugging is enabled.
.. versionchanged:: 3.15
The exception set by :c:func:`PyThreadState_SetAsyncExc` is now raised.
.. c:function:: void PyErr_SetInterrupt()
@ -795,7 +818,7 @@ Exception Classes
.. c:macro:: PyException_HEAD
This is a :term:`soft deprecated` macro including the base fields for an
This is a macro including the base fields for an
exception object.
This was included in Python's C API by mistake and is not designed for use
@ -803,6 +826,8 @@ Exception Classes
:c:func:`PyErr_NewException` or otherwise create a class inheriting from
:c:data:`PyExc_BaseException`.
.. soft-deprecated:: 3.15
Exception Objects
=================
@ -1119,6 +1144,8 @@ Exception types
* :exc:`FloatingPointError`
* * .. c:var:: PyObject *PyExc_GeneratorExit
* :exc:`GeneratorExit`
* * .. c:var:: PyObject *PyExc_ImportCycleError
* :exc:`ImportCycleError`
* * .. c:var:: PyObject *PyExc_ImportError
* :exc:`ImportError`
* * .. c:var:: PyObject *PyExc_IndentationError

11
Doc/c-api/extension-modules.rst
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@ -191,10 +191,10 @@ the :c:data:`Py_mod_multiple_interpreters` slot.
``PyInit`` function
...................
.. deprecated:: 3.15
.. soft-deprecated:: 3.15
This functionality is :term:`soft deprecated`.
It will not get new features, but there are no plans to remove it.
This functionality will not get new features,
but there are no plans to remove it.
Instead of :c:func:`PyModExport_modulename`, an extension module can define
an older-style :dfn:`initialization function` with the signature:
@ -272,10 +272,9 @@ For example, a module called ``spam`` would be defined like this::
Legacy single-phase initialization
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. deprecated:: 3.15
.. soft-deprecated:: 3.15
Single-phase initialization is :term:`soft deprecated`.
It is a legacy mechanism to initialize extension
Single-phase initialization is a legacy mechanism to initialize extension
modules, with known drawbacks and design flaws. Extension module authors
are encouraged to use multi-phase initialization instead.

16
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@ -2,7 +2,7 @@
.. _fileobjects:
File Objects
File objects
------------
.. index:: pair: object; file
@ -123,9 +123,12 @@ the :mod:`io` APIs instead.
Write object *obj* to file object *p*. The only supported flag for *flags* is
:c:macro:`Py_PRINT_RAW`; if given, the :func:`str` of the object is written
instead of the :func:`repr`. Return ``0`` on success or ``-1`` on failure; the
appropriate exception will be set.
instead of the :func:`repr`.
If *obj* is ``NULL``, write the string ``"<NULL>"``.
Return ``0`` on success or ``-1`` on failure; the
appropriate exception will be set.
.. c:function:: int PyFile_WriteString(const char *s, PyObject *p)
@ -133,11 +136,12 @@ the :mod:`io` APIs instead.
failure; the appropriate exception will be set.
Deprecated API
^^^^^^^^^^^^^^
Soft-deprecated API
^^^^^^^^^^^^^^^^^^^
.. soft-deprecated:: 3.15
These are :term:`soft deprecated` APIs that were included in Python's C API
These are APIs that were included in Python's C API
by mistake. They are documented solely for completeness; use other
``PyFile*`` APIs instead.

71
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@ -80,19 +80,18 @@ Floating-Point Objects
.. c:macro:: Py_INFINITY
This macro expands a to constant expression of type :c:expr:`double`, that
This macro expands to a constant expression of type :c:expr:`double`, that
represents the positive infinity.
It is equivalent to the :c:macro:`!INFINITY` macro from the C11 standard
``<math.h>`` header.
.. deprecated:: 3.15
The macro is :term:`soft deprecated`.
.. soft-deprecated:: 3.15
.. c:macro:: Py_NAN
This macro expands a to constant expression of type :c:expr:`double`, that
This macro expands to a constant expression of type :c:expr:`double`, that
represents a quiet not-a-number (qNaN) value.
On most platforms, this is equivalent to the :c:macro:`!NAN` macro from
@ -103,8 +102,7 @@ Floating-Point Objects
Equivalent to :c:macro:`!INFINITY`.
.. deprecated:: 3.14
The macro is :term:`soft deprecated`.
.. soft-deprecated:: 3.14
.. c:macro:: Py_MATH_E
@ -161,8 +159,8 @@ Floating-Point Objects
that is, it is normal, subnormal or zero, but not infinite or NaN.
Return ``0`` otherwise.
.. deprecated:: 3.14
The macro is :term:`soft deprecated`. Use :c:macro:`!isfinite` instead.
.. soft-deprecated:: 3.14
Use :c:macro:`!isfinite` instead.
.. c:macro:: Py_IS_INFINITY(X)
@ -170,8 +168,8 @@ Floating-Point Objects
Return ``1`` if the given floating-point number *X* is positive or negative
infinity. Return ``0`` otherwise.
.. deprecated:: 3.14
The macro is :term:`soft deprecated`. Use :c:macro:`!isinf` instead.
.. soft-deprecated:: 3.14
Use :c:macro:`!isinf` instead.
.. c:macro:: Py_IS_NAN(X)
@ -179,8 +177,8 @@ Floating-Point Objects
Return ``1`` if the given floating-point number *X* is a not-a-number (NaN)
value. Return ``0`` otherwise.
.. deprecated:: 3.14
The macro is :term:`soft deprecated`. Use :c:macro:`!isnan` instead.
.. soft-deprecated:: 3.14
Use :c:macro:`!isnan` instead.
Pack and Unpack functions
@ -190,24 +188,23 @@ The pack and unpack functions provide an efficient platform-independent way to
store floating-point values as byte strings. The Pack routines produce a bytes
string from a C :c:expr:`double`, and the Unpack routines produce a C
:c:expr:`double` from such a bytes string. The suffix (2, 4 or 8) specifies the
number of bytes in the bytes string.
number of bytes in the bytes string:
On platforms that appear to use IEEE 754 formats these functions work by
copying bits. On other platforms, the 2-byte format is identical to the IEEE
754 binary16 half-precision format, the 4-byte format (32-bit) is identical to
the IEEE 754 binary32 single precision format, and the 8-byte format to the
IEEE 754 binary64 double precision format, although the packing of INFs and
NaNs (if such things exist on the platform) isn't handled correctly, and
attempting to unpack a bytes string containing an IEEE INF or NaN will raise an
exception.
* The 2-byte format is the IEEE 754 binary16 half-precision format.
* The 4-byte format is the IEEE 754 binary32 single-precision format.
* The 8-byte format is the IEEE 754 binary64 double-precision format.
Note that NaNs type may not be preserved on IEEE platforms (signaling NaN become
quiet NaN), for example on x86 systems in 32-bit mode.
The NaN type may not be preserved on some platforms while unpacking (signaling
NaNs become quiet NaNs), for example on x86 systems in 32-bit mode.
It's assumed that the :c:expr:`double` type has the IEEE 754 binary64 double
precision format. What happens if it's not true is partly accidental (alas).
On non-IEEE platforms with more precision, or larger dynamic range, than IEEE
754 supports, not all values can be packed; on non-IEEE platforms with less
precision, or smaller dynamic range, not all values can be unpacked. What
happens in such cases is partly accidental (alas).
precision, or smaller dynamic range, not all values can be unpacked. The
packing of special numbers like INFs and NaNs (if such things exist on the
platform) may not be handled correctly, and attempting to unpack a bytes string
containing an IEEE INF or NaN may raise an exception.
.. versionadded:: 3.11
@ -216,19 +213,14 @@ Pack functions
The pack routines write 2, 4 or 8 bytes, starting at *p*. *le* is an
:c:expr:`int` argument, non-zero if you want the bytes string in little-endian
format (exponent last, at ``p+1``, ``p+3``, or ``p+6`` ``p+7``), zero if you
want big-endian format (exponent first, at *p*). The :c:macro:`PY_BIG_ENDIAN`
constant can be used to use the native endian: it is equal to ``1`` on big
endian processor, or ``0`` on little endian processor.
format (exponent last, at ``p+1``, ``p+3``, or ``p+6`` and ``p+7``), zero if you
want big-endian format (exponent first, at *p*). Use the :c:macro:`!PY_LITTLE_ENDIAN`
constant to select the native endian: it is equal to ``0`` on big
endian processor, or ``1`` on little endian processor.
Return value: ``0`` if all is OK, ``-1`` if error (and an exception is set,
most likely :exc:`OverflowError`).
There are two problems on non-IEEE platforms:
* What this does is undefined if *x* is a NaN or infinity.
* ``-0.0`` and ``+0.0`` produce the same bytes string.
.. c:function:: int PyFloat_Pack2(double x, char *p, int le)
Pack a C double as the IEEE 754 binary16 half-precision format.
@ -241,6 +233,9 @@ There are two problems on non-IEEE platforms:
Pack a C double as the IEEE 754 binary64 double precision format.
.. impl-detail::
This function always succeeds in CPython.
Unpack functions
^^^^^^^^^^^^^^^^
@ -248,16 +243,16 @@ Unpack functions
The unpack routines read 2, 4 or 8 bytes, starting at *p*. *le* is an
:c:expr:`int` argument, non-zero if the bytes string is in little-endian format
(exponent last, at ``p+1``, ``p+3`` or ``p+6`` and ``p+7``), zero if big-endian
(exponent first, at *p*). The :c:macro:`PY_BIG_ENDIAN` constant can be used to
use the native endian: it is equal to ``1`` on big endian processor, or ``0``
(exponent first, at *p*). Use the :c:macro:`!PY_LITTLE_ENDIAN` constant to
select the native endian: it is equal to ``0`` on big endian processor, or ``1``
on little endian processor.
Return value: The unpacked double. On error, this is ``-1.0`` and
:c:func:`PyErr_Occurred` is true (and an exception is set, most likely
:exc:`OverflowError`).
Note that on a non-IEEE platform this will refuse to unpack a bytes string that
represents a NaN or infinity.
.. impl-detail::
These functions always succeed in CPython.
.. c:function:: double PyFloat_Unpack2(const char *p, int le)

23
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@ -1,6 +1,6 @@
.. highlight:: c
Frame Objects
Frame objects
-------------
.. c:type:: PyFrameObject
@ -50,6 +50,7 @@ See also :ref:`Reflection <reflection>`.
Return a :term:`strong reference`, or ``NULL`` if *frame* has no outer
frame.
This raises no exceptions.
.. versionadded:: 3.9
@ -146,7 +147,7 @@ See also :ref:`Reflection <reflection>`.
Return the line number that *frame* is currently executing.
Frame Locals Proxies
Frame locals proxies
^^^^^^^^^^^^^^^^^^^^
.. versionadded:: 3.13
@ -168,7 +169,7 @@ See :pep:`667` for more information.
Return non-zero if *obj* is a frame :func:`locals` proxy.
Legacy Local Variable APIs
Legacy local variable APIs
^^^^^^^^^^^^^^^^^^^^^^^^^^
These APIs are :term:`soft deprecated`. As of Python 3.13, they do nothing.
@ -177,40 +178,34 @@ They exist solely for backwards compatibility.
.. c:function:: void PyFrame_LocalsToFast(PyFrameObject *f, int clear)
This function is :term:`soft deprecated` and does nothing.
Prior to Python 3.13, this function would copy the :attr:`~frame.f_locals`
attribute of *f* to the internal "fast" array of local variables, allowing
changes in frame objects to be visible to the interpreter. If *clear* was
true, this function would process variables that were unset in the locals
dictionary.
.. versionchanged:: 3.13
.. soft-deprecated:: 3.13
This function now does nothing.
.. c:function:: void PyFrame_FastToLocals(PyFrameObject *f)
This function is :term:`soft deprecated` and does nothing.
Prior to Python 3.13, this function would copy the internal "fast" array
of local variables (which is used by the interpreter) to the
:attr:`~frame.f_locals` attribute of *f*, allowing changes in local
variables to be visible to frame objects.
.. versionchanged:: 3.13
.. soft-deprecated:: 3.13
This function now does nothing.
.. c:function:: int PyFrame_FastToLocalsWithError(PyFrameObject *f)
This function is :term:`soft deprecated` and does nothing.
Prior to Python 3.13, this function was similar to
:c:func:`PyFrame_FastToLocals`, but would return ``0`` on success, and
``-1`` with an exception set on failure.
.. versionchanged:: 3.13
.. soft-deprecated:: 3.13
This function now does nothing.
@ -218,7 +213,7 @@ They exist solely for backwards compatibility.
:pep:`667`
Internal Frames
Internal frames
^^^^^^^^^^^^^^^
Unless using :pep:`523`, you will not need this.
@ -248,5 +243,3 @@ Unless using :pep:`523`, you will not need this.
Return the currently executing line number, or -1 if there is no line number.
.. versionadded:: 3.12

255
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@ -220,42 +220,6 @@ The :c:member:`~PyTypeObject.tp_traverse` handler accepts a function parameter o
detection; it's not expected that users will need to write their own
visitor functions.
The :c:member:`~PyTypeObject.tp_traverse` handler must have the following type:
.. c:type:: int (*traverseproc)(PyObject *self, visitproc visit, void *arg)
Traversal function for a container object. Implementations must call the
*visit* function for each object directly contained by *self*, with the
parameters to *visit* being the contained object and the *arg* value passed
to the handler. The *visit* function must not be called with a ``NULL``
object argument. If *visit* returns a non-zero value that value should be
returned immediately.
The traversal function must not have any side effects. Implementations
may not modify the reference counts of any Python objects nor create or
destroy any Python objects.
To simplify writing :c:member:`~PyTypeObject.tp_traverse` handlers, a :c:func:`Py_VISIT` macro is
provided. In order to use this macro, the :c:member:`~PyTypeObject.tp_traverse` implementation
must name its arguments exactly *visit* and *arg*:
.. c:macro:: Py_VISIT(o)
If the :c:expr:`PyObject *` *o* is not ``NULL``, call the *visit* callback, with arguments *o*
and *arg*. If *visit* returns a non-zero value, then return it.
Using this macro, :c:member:`~PyTypeObject.tp_traverse` handlers
look like::
static int
my_traverse(Noddy *self, visitproc visit, void *arg)
{
Py_VISIT(self->foo);
Py_VISIT(self->bar);
return 0;
}
The :c:member:`~PyTypeObject.tp_clear` handler must be of the :c:type:`inquiry` type, or ``NULL``
if the object is immutable.
@ -270,6 +234,225 @@ if the object is immutable.
in a reference cycle.
.. _gc-traversal:
Traversal
---------
The :c:member:`~PyTypeObject.tp_traverse` handler must have the following type:
.. c:type:: int (*traverseproc)(PyObject *self, visitproc visit, void *arg)
Traversal function for a garbage-collected object, used by the garbage
collector to detect reference cycles.
Implementations must call the
*visit* function for each object directly contained by *self*, with the
parameters to *visit* being the contained object and the *arg* value passed
to the handler. The *visit* function must not be called with a ``NULL``
object argument. If *visit* returns a non-zero value, that value should be
returned immediately.
A typical :c:member:`!tp_traverse` function calls the :c:func:`Py_VISIT`
convenience macro on each of the instance's members that are Python
objects that the instance owns.
For example, this is a (slightly outdated) traversal function for
the :py:class:`threading.local` class::
static int
local_traverse(PyObject *op, visitproc visit, void *arg)
{
localobject *self = (localobject *) op;
Py_VISIT(Py_TYPE(self));
Py_VISIT(self->args);
Py_VISIT(self->kw);
Py_VISIT(self->dict);
return 0;
}
.. note::
:c:func:`Py_VISIT` requires the *visit* and *arg* parameters to
:c:func:`!local_traverse` to have these specific names; don't name them just
anything.
Instances of :ref:`heap-allocated types <heap-types>` hold a reference to
their type. Their traversal function must therefore visit the type::
Py_VISIT(Py_TYPE(self));
Alternately, the type may delegate this responsibility by
calling ``tp_traverse`` of a heap-allocated superclass (or another
heap-allocated type, if applicable).
If they do not, the type object may not be garbage-collected.
If the :c:macro:`Py_TPFLAGS_MANAGED_DICT` bit is set in the
:c:member:`~PyTypeObject.tp_flags` field, the traverse function must call
:c:func:`PyObject_VisitManagedDict` like this::
int err = PyObject_VisitManagedDict((PyObject*)self, visit, arg);
if (err) {
return err;
}
Only the members that the instance *owns* (by having
:term:`strong references <strong reference>` to them) must be
visited. For instance, if an object supports weak references via the
:c:member:`~PyTypeObject.tp_weaklist` slot, the pointer supporting
the linked list (what *tp_weaklist* points to) must **not** be
visited as the instance does not directly own the weak references to itself.
The traversal function has a limitation:
.. warning::
The traversal function must not have any side effects. Implementations
may not modify the reference counts of any Python objects nor create or
destroy any Python objects, directly or indirectly.
This means that *most* Python C API functions may not be used, since
they can raise a new exception, return a new reference to a result object,
have internal logic that uses side effects.
Also, unless documented otherwise, functions that happen to not have side
effects may start having them in future versions, without warning.
For a list of safe functions, see a
:ref:`separate section <duringgc-functions>` below.
.. note::
The :c:func:`Py_VISIT` call may be skipped for those members that provably
cannot participate in reference cycles.
In the ``local_traverse`` example above, there is also a ``self->key``
member, but it can only be ``NULL`` or a Python string and therefore
cannot be part of a reference cycle.
On the other hand, even if you know a member can never be part of a cycle,
as a debugging aid you may want to visit it anyway just so the :mod:`gc`
module's :func:`~gc.get_referents` function will include it.
.. note::
The :c:member:`~PyTypeObject.tp_traverse` function can be called from any
thread.
.. impl-detail::
Garbage collection is a "stop-the-world" operation:
even in :term:`free threading` builds, only one thread state is
:term:`attached <attached thread state>` when :c:member:`!tp_traverse`
handlers run.
.. versionchanged:: 3.9
Heap-allocated types are expected to visit ``Py_TYPE(self)`` in
``tp_traverse``. In earlier versions of Python, due to
`bug 40217 <https://bugs.python.org/issue40217>`_, doing this
may lead to crashes in subclasses.
To simplify writing :c:member:`~PyTypeObject.tp_traverse` handlers,
a :c:func:`Py_VISIT` macro is provided.
In order to use this macro, the :c:member:`~PyTypeObject.tp_traverse`
implementation must name its arguments exactly *visit* and *arg*:
.. c:macro:: Py_VISIT(o)
If the :c:expr:`PyObject *` *o* is not ``NULL``, call the *visit*
callback, with arguments *o* and *arg*.
If *visit* returns a non-zero value, then return it.
This corresponds roughly to::
#define Py_VISIT(o) \
if (op) { \
int visit_result = visit(o, arg); \
if (visit_result != 0) { \
return visit_result; \
} \
}
Traversal-safe functions
^^^^^^^^^^^^^^^^^^^^^^^^
The following functions and macros are safe to use in a
:c:member:`~PyTypeObject.tp_traverse` handler:
* the *visit* function passed to ``tp_traverse``
* :c:func:`Py_VISIT`
* :c:func:`Py_SIZE`
* :c:func:`Py_TYPE`: if called from a :c:member:`!tp_traverse` handler,
:c:func:`!Py_TYPE`'s result will be valid for the duration of the handler call
* :c:func:`PyObject_VisitManagedDict`
* :c:func:`PyObject_TypeCheck`, :c:func:`PyType_IsSubtype`,
:c:func:`PyType_HasFeature`
* :samp:`Py{<type>}_Check` and :samp:`Py{<type>}_CheckExact` -- for example,
:c:func:`PyTuple_Check`
* :ref:`duringgc-functions`
.. _duringgc-functions:
"DuringGC" functions
^^^^^^^^^^^^^^^^^^^^
The following functions should *only* be used in a
:c:member:`~PyTypeObject.tp_traverse` handler; calling them in other
contexts may have unintended consequences.
These functions act like their counterparts without the ``_DuringGC`` suffix,
but they are guaranteed to not have side effects, they do not set an exception
on failure, and they return/set :term:`borrowed references <borrowed reference>`
as detailed in the individual documentation.
Note that these functions may fail (return ``NULL`` or ``-1``),
but as they do not set an exception, no error information is available.
In some cases, failure is not distinguishable from a successful ``NULL`` result.
.. c:function:: void *PyObject_GetTypeData_DuringGC(PyObject *o, PyTypeObject *cls)
void *PyObject_GetItemData_DuringGC(PyObject *o)
void *PyType_GetModuleState_DuringGC(PyTypeObject *type)
void *PyModule_GetState_DuringGC(PyObject *module)
int PyModule_GetToken_DuringGC(PyObject *module, void** result)
See :ref:`duringgc-functions` for common information.
.. versionadded:: next
.. seealso::
:c:func:`PyObject_GetTypeData`,
:c:func:`PyObject_GetItemData`,
:c:func:`PyType_GetModuleState`,
:c:func:`PyModule_GetState`,
:c:func:`PyModule_GetToken`,
:c:func:`PyType_GetBaseByToken`
.. c:function:: int PyType_GetBaseByToken_DuringGC(PyTypeObject *type, void *tp_token, PyTypeObject **result)
See :ref:`duringgc-functions` for common information.
Sets *\*result* to a :term:`borrowed reference` rather than a strong one.
The reference is valid for the duration
of the :c:member:`!tp_traverse` handler call.
.. versionadded:: next
.. seealso:: :c:func:`PyType_GetBaseByToken`
.. c:function:: PyObject* PyType_GetModule_DuringGC(PyTypeObject *type)
PyObject* PyType_GetModuleByToken_DuringGC(PyTypeObject *type, const void *mod_token)
See :ref:`duringgc-functions` for common information.
These functions return a :term:`borrowed reference`, which is
valid for the duration of the :c:member:`!tp_traverse` handler call.
.. versionadded:: next
.. seealso::
:c:func:`PyType_GetModule`,
:c:func:`PyType_GetModuleByToken`
Controlling the Garbage Collector State
---------------------------------------

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@ -90,7 +90,9 @@ Deprecated API
.. c:macro:: PyAsyncGenASend_CheckExact(op)
This is a :term:`soft deprecated` API that was included in Python's C API
This is an API that was included in Python's C API
by mistake.
It is solely here for completeness; do not use this API.
.. soft-deprecated:: 3.14

54
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@ -346,6 +346,60 @@ Importing Modules
.. versionadded:: 3.14
.. c:function:: PyImport_LazyImportsMode PyImport_GetLazyImportsMode()
Gets the current lazy imports mode.
.. versionadded:: 3.15
.. c:function:: PyObject* PyImport_GetLazyImportsFilter()
Return a :term:`strong reference` to the current lazy imports filter,
or ``NULL`` if none exists. This function always succeeds.
.. versionadded:: 3.15
.. c:function:: int PyImport_SetLazyImportsMode(PyImport_LazyImportsMode mode)
Similar to :c:func:`PyImport_ImportModuleAttr`, but names are UTF-8 encoded
strings instead of Python :class:`str` objects.
This function always returns ``0``.
.. versionadded:: 3.15
.. c:function:: int PyImport_SetLazyImportsFilter(PyObject *filter)
Sets the current lazy imports filter. The *filter* should be a callable that
will receive ``(importing_module_name, imported_module_name, [fromlist])``
when an import can potentially be lazy. The ``imported_module_name`` value
is the resolved module name, so ``lazy from .spam import eggs`` passes
``package.spam``. The callable must return ``True`` if the import should be
lazy and ``False`` otherwise.
Return ``0`` on success and ``-1`` with an exception set otherwise.
.. versionadded:: 3.15
.. c:type:: PyImport_LazyImportsMode
Enumeration of possible lazy import modes.
.. c:enumerator:: PyImport_LAZY_NORMAL
Respect the ``lazy`` keyword in source code. This is the default mode.
.. c:enumerator:: PyImport_LAZY_ALL
Make all imports lazy by default.
.. c:enumerator:: PyImport_LAZY_NONE
Disable lazy imports entirely. Even explicit ``lazy`` statements become
eager imports.
.. versionadded:: 3.15
.. c:function:: PyObject* PyImport_CreateModuleFromInitfunc(PyObject *spec, PyObject* (*initfunc)(void))
This function is a building block that enables embedders to implement

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@ -1,7 +1,7 @@
.. _c-api-index:
##################################
Python/C API Reference Manual
Python/C API reference manual
##################################
This manual documents the API used by C and C++ programmers who want to write
@ -21,7 +21,12 @@ document the API functions in detail.
utilities.rst
abstract.rst
concrete.rst
init.rst
interp-lifecycle.rst
threads.rst
synchronization.rst
tls.rst
subinterpreters.rst
profiling.rst
init_config.rst
memory.rst
objimpl.rst

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@ -544,9 +544,9 @@ Configuration Options
Visibility:
* Public: Can by get by :c:func:`PyConfig_Get` and set by
* Public: Can be retrieved by :c:func:`PyConfig_Get` and set by
:c:func:`PyConfig_Set`.
* Read-only: Can by get by :c:func:`PyConfig_Get`, but cannot be set by
* Read-only: Can be retrieved by :c:func:`PyConfig_Get`, but cannot be set by
:c:func:`PyConfig_Set`.
@ -1153,7 +1153,7 @@ PyConfig
Most ``PyConfig`` methods :ref:`preinitialize Python <c-preinit>` if needed.
In that case, the Python preinitialization configuration
(:c:type:`PyPreConfig`) in based on the :c:type:`PyConfig`. If configuration
(:c:type:`PyPreConfig`) is based on the :c:type:`PyConfig`. If configuration
fields which are in common with :c:type:`PyPreConfig` are tuned, they must
be set before calling a :c:type:`PyConfig` method:
@ -1807,10 +1807,10 @@ PyConfig
.. c:member:: wchar_t* run_presite
``package.module`` path to module that should be imported before
``site.py`` is run.
``module`` or ``module:func`` entry point that should be executed before
the :mod:`site` module is imported.
Set by the :option:`-X presite=package.module <-X>` command-line
Set by the :option:`-X presite=module:func <-X>` command-line
option and the :envvar:`PYTHON_PRESITE` environment variable.
The command-line option takes precedence.
@ -2299,13 +2299,91 @@ Py_GetArgcArgv()
See also :c:member:`PyConfig.orig_argv` member.
Delaying main module execution
==============================
In some embedding use cases, it may be desirable to separate interpreter initialization
from the execution of the main module.
Multi-Phase Initialization Private Provisional API
==================================================
This separation can be achieved by setting ``PyConfig.run_command`` to the empty
string during initialization (to prevent the interpreter from dropping into the
interactive prompt), and then subsequently executing the desired main module
code using ``__main__.__dict__`` as the global namespace.
This section is a private provisional API introducing multi-phase
initialization, the core feature of :pep:`432`:
* "Core" initialization phase, "bare minimum Python":
* Builtin types;
* Builtin exceptions;
* Builtin and frozen modules;
* The :mod:`sys` module is only partially initialized
(ex: :data:`sys.path` doesn't exist yet).
* "Main" initialization phase, Python is fully initialized:
* Install and configure :mod:`importlib`;
* Apply the :ref:`Path Configuration <init-path-config>`;
* Install signal handlers;
* Finish :mod:`sys` module initialization (ex: create :data:`sys.stdout`
and :data:`sys.path`);
* Enable optional features like :mod:`faulthandler` and :mod:`tracemalloc`;
* Import the :mod:`site` module;
* etc.
Private provisional API:
.. c:member:: int PyConfig._init_main
If set to ``0``, :c:func:`Py_InitializeFromConfig` stops at the "Core"
initialization phase.
.. c:function:: PyStatus _Py_InitializeMain(void)
Move to the "Main" initialization phase, finish the Python initialization.
No module is imported during the "Core" phase and the ``importlib`` module is
not configured: the :ref:`Path Configuration <init-path-config>` is only
applied during the "Main" phase. It may allow to customize Python in Python to
override or tune the :ref:`Path Configuration <init-path-config>`, maybe
install a custom :data:`sys.meta_path` importer or an import hook, etc.
It may become possible to calculate the :ref:`Path Configuration
<init-path-config>` in Python, after the Core phase and before the Main phase,
which is one of the :pep:`432` motivation.
The "Core" phase is not properly defined: what should be and what should
not be available at this phase is not specified yet. The API is marked
as private and provisional: the API can be modified or even be removed
anytime until a proper public API is designed.
Example running Python code between "Core" and "Main" initialization
phases::
void init_python(void)
{
PyStatus status;
PyConfig config;
PyConfig_InitPythonConfig(&config);
config._init_main = 0;
/* ... customize 'config' configuration ... */
status = Py_InitializeFromConfig(&config);
PyConfig_Clear(&config);
if (PyStatus_Exception(status)) {
Py_ExitStatusException(status);
}
/* Use sys.stderr because sys.stdout is only created
by _Py_InitializeMain() */
int res = PyRun_SimpleString(
"import sys; "
"print('Run Python code before _Py_InitializeMain', "
"file=sys.stderr)");
if (res < 0) {
exit(1);
}
/* ... put more configuration code here ... */
status = _Py_InitializeMain();
if (PyStatus_Exception(status)) {
Py_ExitStatusException(status);
}
}

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@ -0,0 +1,802 @@
.. highlight:: c
.. _initialization:
Interpreter initialization and finalization
===========================================
See :ref:`Python Initialization Configuration <init-config>` for details
on how to configure the interpreter prior to initialization.
.. _pre-init-safe:
Before Python initialization
----------------------------
In an application embedding Python, the :c:func:`Py_Initialize` function must
be called before using any other Python/C API functions; with the exception of
a few functions and the :ref:`global configuration variables
<global-conf-vars>`.
The following functions can be safely called before Python is initialized:
* Functions that initialize the interpreter:
* :c:func:`Py_Initialize`
* :c:func:`Py_InitializeEx`
* :c:func:`Py_InitializeFromConfig`
* :c:func:`Py_BytesMain`
* :c:func:`Py_Main`
* the runtime pre-initialization functions covered in :ref:`init-config`
* Configuration functions:
* :c:func:`PyImport_AppendInittab`
* :c:func:`PyImport_ExtendInittab`
* :c:func:`!PyInitFrozenExtensions`
* :c:func:`PyMem_SetAllocator`
* :c:func:`PyMem_SetupDebugHooks`
* :c:func:`PyObject_SetArenaAllocator`
* :c:func:`Py_SetProgramName`
* :c:func:`Py_SetPythonHome`
* the configuration functions covered in :ref:`init-config`
* Informative functions:
* :c:func:`Py_IsInitialized`
* :c:func:`PyMem_GetAllocator`
* :c:func:`PyObject_GetArenaAllocator`
* :c:func:`Py_GetBuildInfo`
* :c:func:`Py_GetCompiler`
* :c:func:`Py_GetCopyright`
* :c:func:`Py_GetPlatform`
* :c:func:`Py_GetVersion`
* :c:func:`Py_IsInitialized`
* Utilities:
* :c:func:`Py_DecodeLocale`
* the status reporting and utility functions covered in :ref:`init-config`
* Memory allocators:
* :c:func:`PyMem_RawMalloc`
* :c:func:`PyMem_RawRealloc`
* :c:func:`PyMem_RawCalloc`
* :c:func:`PyMem_RawFree`
* Synchronization:
* :c:func:`PyMutex_Lock`
* :c:func:`PyMutex_Unlock`
.. note::
Despite their apparent similarity to some of the functions listed above,
the following functions **should not be called** before the interpreter has
been initialized: :c:func:`Py_EncodeLocale`, :c:func:`PyEval_InitThreads`, and
:c:func:`Py_RunMain`.
.. _global-conf-vars:
Global configuration variables
------------------------------
Python has variables for the global configuration to control different features
and options. By default, these flags are controlled by :ref:`command line
options <using-on-interface-options>`.
When a flag is set by an option, the value of the flag is the number of times
that the option was set. For example, ``-b`` sets :c:data:`Py_BytesWarningFlag`
to 1 and ``-bb`` sets :c:data:`Py_BytesWarningFlag` to 2.
.. c:var:: int Py_BytesWarningFlag
This API is kept for backward compatibility: setting
:c:member:`PyConfig.bytes_warning` should be used instead, see :ref:`Python
Initialization Configuration <init-config>`.
Issue a warning when comparing :class:`bytes` or :class:`bytearray` with
:class:`str` or :class:`bytes` with :class:`int`. Issue an error if greater
or equal to ``2``.
Set by the :option:`-b` option.
.. deprecated-removed:: 3.12 3.15
.. c:var:: int Py_DebugFlag
This API is kept for backward compatibility: setting
:c:member:`PyConfig.parser_debug` should be used instead, see :ref:`Python
Initialization Configuration <init-config>`.
Turn on parser debugging output (for expert only, depending on compilation
options).
Set by the :option:`-d` option and the :envvar:`PYTHONDEBUG` environment
variable.
.. deprecated-removed:: 3.12 3.15
.. c:var:: int Py_DontWriteBytecodeFlag
This API is kept for backward compatibility: setting
:c:member:`PyConfig.write_bytecode` should be used instead, see :ref:`Python
Initialization Configuration <init-config>`.
If set to non-zero, Python won't try to write ``.pyc`` files on the
import of source modules.
Set by the :option:`-B` option and the :envvar:`PYTHONDONTWRITEBYTECODE`
environment variable.
.. deprecated-removed:: 3.12 3.15
.. c:var:: int Py_FrozenFlag
This API is kept for backward compatibility: setting
:c:member:`PyConfig.pathconfig_warnings` should be used instead, see
:ref:`Python Initialization Configuration <init-config>`.
Private flag used by ``_freeze_module`` and ``frozenmain`` programs.
.. deprecated-removed:: 3.12 3.15
.. c:var:: int Py_HashRandomizationFlag
This API is kept for backward compatibility: setting
:c:member:`PyConfig.hash_seed` and :c:member:`PyConfig.use_hash_seed` should
be used instead, see :ref:`Python Initialization Configuration
<init-config>`.
Set to ``1`` if the :envvar:`PYTHONHASHSEED` environment variable is set to
a non-empty string.
If the flag is non-zero, read the :envvar:`PYTHONHASHSEED` environment
variable to initialize the secret hash seed.
.. deprecated-removed:: 3.12 3.15
.. c:var:: int Py_IgnoreEnvironmentFlag
This API is kept for backward compatibility: setting
:c:member:`PyConfig.use_environment` should be used instead, see
:ref:`Python Initialization Configuration <init-config>`.
Ignore all :envvar:`!PYTHON*` environment variables, e.g.
:envvar:`PYTHONPATH` and :envvar:`PYTHONHOME`, that might be set.
Set by the :option:`-E` and :option:`-I` options.
.. deprecated-removed:: 3.12 3.15
.. c:var:: int Py_InspectFlag
This API is kept for backward compatibility: setting
:c:member:`PyConfig.inspect` should be used instead, see
:ref:`Python Initialization Configuration <init-config>`.
When a script is passed as first argument or the :option:`-c` option is used,
enter interactive mode after executing the script or the command, even when
:data:`sys.stdin` does not appear to be a terminal.
Set by the :option:`-i` option and the :envvar:`PYTHONINSPECT` environment
variable.
.. deprecated-removed:: 3.12 3.15
.. c:var:: int Py_InteractiveFlag
This API is kept for backward compatibility: setting
:c:member:`PyConfig.interactive` should be used instead, see
:ref:`Python Initialization Configuration <init-config>`.
Set by the :option:`-i` option.
.. deprecated-removed:: 3.12 3.15
.. c:var:: int Py_IsolatedFlag
This API is kept for backward compatibility: setting
:c:member:`PyConfig.isolated` should be used instead, see
:ref:`Python Initialization Configuration <init-config>`.
Run Python in isolated mode. In isolated mode :data:`sys.path` contains
neither the script's directory nor the user's site-packages directory.
Set by the :option:`-I` option.
.. versionadded:: 3.4
.. deprecated-removed:: 3.12 3.15
.. c:var:: int Py_LegacyWindowsFSEncodingFlag
This API is kept for backward compatibility: setting
:c:member:`PyPreConfig.legacy_windows_fs_encoding` should be used instead, see
:ref:`Python Initialization Configuration <init-config>`.
If the flag is non-zero, use the ``mbcs`` encoding with ``replace`` error
handler, instead of the UTF-8 encoding with ``surrogatepass`` error handler,
for the :term:`filesystem encoding and error handler`.
Set to ``1`` if the :envvar:`PYTHONLEGACYWINDOWSFSENCODING` environment
variable is set to a non-empty string.
See :pep:`529` for more details.
.. availability:: Windows.
.. deprecated-removed:: 3.12 3.15
.. c:var:: int Py_LegacyWindowsStdioFlag
This API is kept for backward compatibility: setting
:c:member:`PyConfig.legacy_windows_stdio` should be used instead, see
:ref:`Python Initialization Configuration <init-config>`.
If the flag is non-zero, use :class:`io.FileIO` instead of
:class:`!io._WindowsConsoleIO` for :mod:`sys` standard streams.
Set to ``1`` if the :envvar:`PYTHONLEGACYWINDOWSSTDIO` environment
variable is set to a non-empty string.
See :pep:`528` for more details.
.. availability:: Windows.
.. deprecated-removed:: 3.12 3.15
.. c:var:: int Py_NoSiteFlag
This API is kept for backward compatibility: setting
:c:member:`PyConfig.site_import` should be used instead, see
:ref:`Python Initialization Configuration <init-config>`.
Disable the import of the module :mod:`site` and the site-dependent
manipulations of :data:`sys.path` that it entails. Also disable these
manipulations if :mod:`site` is explicitly imported later (call
:func:`site.main` if you want them to be triggered).
Set by the :option:`-S` option.
.. deprecated-removed:: 3.12 3.15
.. c:var:: int Py_NoUserSiteDirectory
This API is kept for backward compatibility: setting
:c:member:`PyConfig.user_site_directory` should be used instead, see
:ref:`Python Initialization Configuration <init-config>`.
Don't add the :data:`user site-packages directory <site.USER_SITE>` to
:data:`sys.path`.
Set by the :option:`-s` and :option:`-I` options, and the
:envvar:`PYTHONNOUSERSITE` environment variable.
.. deprecated-removed:: 3.12 3.15
.. c:var:: int Py_OptimizeFlag
This API is kept for backward compatibility: setting
:c:member:`PyConfig.optimization_level` should be used instead, see
:ref:`Python Initialization Configuration <init-config>`.
Set by the :option:`-O` option and the :envvar:`PYTHONOPTIMIZE` environment
variable.
.. deprecated-removed:: 3.12 3.15
.. c:var:: int Py_QuietFlag
This API is kept for backward compatibility: setting
:c:member:`PyConfig.quiet` should be used instead, see :ref:`Python
Initialization Configuration <init-config>`.
Don't display the copyright and version messages even in interactive mode.
Set by the :option:`-q` option.
.. versionadded:: 3.2
.. deprecated-removed:: 3.12 3.15
.. c:var:: int Py_UnbufferedStdioFlag
This API is kept for backward compatibility: setting
:c:member:`PyConfig.buffered_stdio` should be used instead, see :ref:`Python
Initialization Configuration <init-config>`.
Force the stdout and stderr streams to be unbuffered.
Set by the :option:`-u` option and the :envvar:`PYTHONUNBUFFERED`
environment variable.
.. deprecated-removed:: 3.12 3.15
.. c:var:: int Py_VerboseFlag
This API is kept for backward compatibility: setting
:c:member:`PyConfig.verbose` should be used instead, see :ref:`Python
Initialization Configuration <init-config>`.
Print a message each time a module is initialized, showing the place
(filename or built-in module) from which it is loaded. If greater or equal
to ``2``, print a message for each file that is checked for when
searching for a module. Also provides information on module cleanup at exit.
Set by the :option:`-v` option and the :envvar:`PYTHONVERBOSE` environment
variable.
.. deprecated-removed:: 3.12 3.15
Initializing and finalizing the interpreter
-------------------------------------------
.. c:function:: void Py_Initialize()
.. index::
single: PyEval_InitThreads()
single: modules (in module sys)
single: path (in module sys)
pair: module; builtins
pair: module; __main__
pair: module; sys
triple: module; search; path
single: Py_FinalizeEx (C function)
Initialize the Python interpreter. In an application embedding Python,
this should be called before using any other Python/C API functions; see
:ref:`Before Python Initialization <pre-init-safe>` for the few exceptions.
This initializes the table of loaded modules (``sys.modules``), and creates
the fundamental modules :mod:`builtins`, :mod:`__main__` and :mod:`sys`.
It also initializes the module search path (``sys.path``). It does not set
``sys.argv``; use the :ref:`Python Initialization Configuration <init-config>`
API for that. This is a no-op when called for a second time (without calling
:c:func:`Py_FinalizeEx` first). There is no return value; it is a fatal
error if the initialization fails.
Use :c:func:`Py_InitializeFromConfig` to customize the
:ref:`Python Initialization Configuration <init-config>`.
.. note::
On Windows, changes the console mode from ``O_TEXT`` to ``O_BINARY``,
which will also affect non-Python uses of the console using the C Runtime.
.. c:function:: void Py_InitializeEx(int initsigs)
This function works like :c:func:`Py_Initialize` if *initsigs* is ``1``. If
*initsigs* is ``0``, it skips initialization registration of signal handlers,
which may be useful when CPython is embedded as part of a larger application.
Use :c:func:`Py_InitializeFromConfig` to customize the
:ref:`Python Initialization Configuration <init-config>`.
.. c:function:: PyStatus Py_InitializeFromConfig(const PyConfig *config)
Initialize Python from *config* configuration, as described in
:ref:`init-from-config`.
See the :ref:`init-config` section for details on pre-initializing the
interpreter, populating the runtime configuration structure, and querying
the returned status structure.
.. c:function:: int Py_IsInitialized()
Return true (nonzero) when the Python interpreter has been initialized, false
(zero) if not. After :c:func:`Py_FinalizeEx` is called, this returns false until
:c:func:`Py_Initialize` is called again.
.. versionchanged:: next
This function no longer returns true until initialization has fully
completed, including import of the :mod:`site` module. Previously it
could return true while :c:func:`Py_Initialize` was still running.
.. c:function:: int Py_IsFinalizing()
Return true (non-zero) if the main Python interpreter is
:term:`shutting down <interpreter shutdown>`. Return false (zero) otherwise.
.. versionadded:: 3.13
.. c:function:: int Py_FinalizeEx()
Undo all initializations made by :c:func:`Py_Initialize` and subsequent use of
Python/C API functions, and destroy all sub-interpreters (see
:c:func:`Py_NewInterpreter` below) that were created and not yet destroyed since
the last call to :c:func:`Py_Initialize`. This is a no-op when called for a second
time (without calling :c:func:`Py_Initialize` again first).
Since this is the reverse of :c:func:`Py_Initialize`, it should be called
in the same thread with the same interpreter active. That means
the main thread and the main interpreter.
This should never be called while :c:func:`Py_RunMain` is running.
Normally the return value is ``0``.
If there were errors during finalization (flushing buffered data),
``-1`` is returned.
Note that Python will do a best effort at freeing all memory allocated by the Python
interpreter. Therefore, any C-Extension should make sure to correctly clean up all
of the previously allocated PyObjects before using them in subsequent calls to
:c:func:`Py_Initialize`. Otherwise it could introduce vulnerabilities and incorrect
behavior.
This function is provided for a number of reasons. An embedding application
might want to restart Python without having to restart the application itself.
An application that has loaded the Python interpreter from a dynamically
loadable library (or DLL) might want to free all memory allocated by Python
before unloading the DLL. During a hunt for memory leaks in an application a
developer might want to free all memory allocated by Python before exiting from
the application.
**Bugs and caveats:** The destruction of modules and objects in modules is done
in random order; this may cause destructors (:meth:`~object.__del__` methods) to fail
when they depend on other objects (even functions) or modules. Dynamically
loaded extension modules loaded by Python are not unloaded. Small amounts of
memory allocated by the Python interpreter may not be freed (if you find a leak,
please report it). Memory tied up in circular references between objects is not
freed. Interned strings will all be deallocated regardless of their reference count.
Some memory allocated by extension modules may not be freed. Some extensions may not
work properly if their initialization routine is called more than once; this can
happen if an application calls :c:func:`Py_Initialize` and :c:func:`Py_FinalizeEx`
more than once. :c:func:`Py_FinalizeEx` must not be called recursively from
within itself. Therefore, it must not be called by any code that may be run
as part of the interpreter shutdown process, such as :py:mod:`atexit`
handlers, object finalizers, or any code that may be run while flushing the
stdout and stderr files.
.. audit-event:: cpython._PySys_ClearAuditHooks "" c.Py_FinalizeEx
.. versionadded:: 3.6
.. c:function:: void Py_Finalize()
This is a backwards-compatible version of :c:func:`Py_FinalizeEx` that
disregards the return value.
.. c:function:: int Py_BytesMain(int argc, char **argv)
Similar to :c:func:`Py_Main` but *argv* is an array of bytes strings,
allowing the calling application to delegate the text decoding step to
the CPython runtime.
.. versionadded:: 3.8
.. c:function:: int Py_Main(int argc, wchar_t **argv)
The main program for the standard interpreter, encapsulating a full
initialization/finalization cycle, as well as additional
behaviour to implement reading configurations settings from the environment
and command line, and then executing ``__main__`` in accordance with
:ref:`using-on-cmdline`.
This is made available for programs which wish to support the full CPython
command line interface, rather than just embedding a Python runtime in a
larger application.
The *argc* and *argv* parameters are similar to those which are passed to a
C program's :c:func:`main` function, except that the *argv* entries are first
converted to ``wchar_t`` using :c:func:`Py_DecodeLocale`. It is also
important to note that the argument list entries may be modified to point to
strings other than those passed in (however, the contents of the strings
pointed to by the argument list are not modified).
The return value is ``2`` if the argument list does not represent a valid
Python command line, and otherwise the same as :c:func:`Py_RunMain`.
In terms of the CPython runtime configuration APIs documented in the
:ref:`runtime configuration <init-config>` section (and without accounting
for error handling), ``Py_Main`` is approximately equivalent to::
PyConfig config;
PyConfig_InitPythonConfig(&config);
PyConfig_SetArgv(&config, argc, argv);
Py_InitializeFromConfig(&config);
PyConfig_Clear(&config);
Py_RunMain();
In normal usage, an embedding application will call this function
*instead* of calling :c:func:`Py_Initialize`, :c:func:`Py_InitializeEx` or
:c:func:`Py_InitializeFromConfig` directly, and all settings will be applied
as described elsewhere in this documentation. If this function is instead
called *after* a preceding runtime initialization API call, then exactly
which environmental and command line configuration settings will be updated
is version dependent (as it depends on which settings correctly support
being modified after they have already been set once when the runtime was
first initialized).
.. c:function:: int Py_RunMain(void)
Executes the main module in a fully configured CPython runtime.
Executes the command (:c:member:`PyConfig.run_command`), the script
(:c:member:`PyConfig.run_filename`) or the module
(:c:member:`PyConfig.run_module`) specified on the command line or in the
configuration. If none of these values are set, runs the interactive Python
prompt (REPL) using the ``__main__`` module's global namespace.
If :c:member:`PyConfig.inspect` is not set (the default), the return value
will be ``0`` if the interpreter exits normally (that is, without raising
an exception), the exit status of an unhandled :exc:`SystemExit`, or ``1``
for any other unhandled exception.
If :c:member:`PyConfig.inspect` is set (such as when the :option:`-i` option
is used), rather than returning when the interpreter exits, execution will
instead resume in an interactive Python prompt (REPL) using the ``__main__``
module's global namespace. If the interpreter exited with an exception, it
is immediately raised in the REPL session. The function return value is
then determined by the way the *REPL session* terminates: ``0``, ``1``, or
the status of a :exc:`SystemExit`, as specified above.
This function always finalizes the Python interpreter before it returns.
See :ref:`Python Configuration <init-python-config>` for an example of a
customized Python that always runs in isolated mode using
:c:func:`Py_RunMain`.
.. c:function:: int PyUnstable_AtExit(PyInterpreterState *interp, void (*func)(void *), void *data)
Register an :mod:`atexit` callback for the target interpreter *interp*.
This is similar to :c:func:`Py_AtExit`, but takes an explicit interpreter and
data pointer for the callback.
There must be an :term:`attached thread state` for *interp*.
.. versionadded:: 3.13
.. _cautions-regarding-runtime-finalization:
Cautions regarding runtime finalization
---------------------------------------
In the late stage of :term:`interpreter shutdown`, after attempting to wait for
non-daemon threads to exit (though this can be interrupted by
:class:`KeyboardInterrupt`) and running the :mod:`atexit` functions, the runtime
is marked as *finalizing*: :c:func:`Py_IsFinalizing` and
:func:`sys.is_finalizing` return true. At this point, only the *finalization
thread* that initiated finalization (typically the main thread) is allowed to
acquire the :term:`GIL`.
If any thread, other than the finalization thread, attempts to attach a :term:`thread state`
during finalization, either explicitly or
implicitly, the thread enters **a permanently blocked state**
where it remains until the program exits. In most cases this is harmless, but this can result
in deadlock if a later stage of finalization attempts to acquire a lock owned by the
blocked thread, or otherwise waits on the blocked thread.
Gross? Yes. This prevents random crashes and/or unexpectedly skipped C++
finalizations further up the call stack when such threads were forcibly exited
here in CPython 3.13 and earlier. The CPython runtime :term:`thread state` C APIs
have never had any error reporting or handling expectations at :term:`thread state`
attachment time that would've allowed for graceful exit from this situation. Changing that
would require new stable C APIs and rewriting the majority of C code in the
CPython ecosystem to use those with error handling.
Process-wide parameters
-----------------------
.. c:function:: void Py_SetProgramName(const wchar_t *name)
.. index::
single: Py_Initialize()
single: main()
This API is kept for backward compatibility: setting
:c:member:`PyConfig.program_name` should be used instead, see :ref:`Python
Initialization Configuration <init-config>`.
This function should be called before :c:func:`Py_Initialize` is called for
the first time, if it is called at all. It tells the interpreter the value
of the ``argv[0]`` argument to the :c:func:`main` function of the program
(converted to wide characters).
This is used by some other functions below to find
the Python run-time libraries relative to the interpreter executable. The
default value is ``'python'``. The argument should point to a
zero-terminated wide character string in static storage whose contents will not
change for the duration of the program's execution. No code in the Python
interpreter will change the contents of this storage.
Use :c:func:`Py_DecodeLocale` to decode a bytes string to get a
:c:expr:`wchar_t*` string.
.. deprecated-removed:: 3.11 3.15
.. c:function:: const char* Py_GetVersion()
Return the version of this Python interpreter. This is a string that looks
something like ::
"3.0a5+ (py3k:63103M, May 12 2008, 00:53:55) \n[GCC 4.2.3]"
.. index:: single: version (in module sys)
The first word (up to the first space character) is the current Python version;
the first characters are the major and minor version separated by a
period. The returned string points into static storage; the caller should not
modify its value. The value is available to Python code as :data:`sys.version`.
See also the :c:var:`Py_Version` constant.
.. c:function:: const char* Py_GetPlatform()
.. index:: single: platform (in module sys)
Return the platform identifier for the current platform. On Unix, this is
formed from the "official" name of the operating system, converted to lower
case, followed by the major revision number; e.g., for Solaris 2.x, which is
also known as SunOS 5.x, the value is ``'sunos5'``. On macOS, it is
``'darwin'``. On Windows, it is ``'win'``. The returned string points into
static storage; the caller should not modify its value. The value is available
to Python code as ``sys.platform``.
.. c:function:: const char* Py_GetCopyright()
Return the official copyright string for the current Python version, for example
``'Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam'``
.. index:: single: copyright (in module sys)
The returned string points into static storage; the caller should not modify its
value. The value is available to Python code as ``sys.copyright``.
.. c:function:: const char* Py_GetCompiler()
Return an indication of the compiler used to build the current Python version,
in square brackets, for example::
"[GCC 2.7.2.2]"
.. index:: single: version (in module sys)
The returned string points into static storage; the caller should not modify its
value. The value is available to Python code as part of the variable
``sys.version``.
.. c:function:: const char* Py_GetBuildInfo()
Return information about the sequence number and build date and time of the
current Python interpreter instance, for example ::
"#67, Aug 1 1997, 22:34:28"
.. index:: single: version (in module sys)
The returned string points into static storage; the caller should not modify its
value. The value is available to Python code as part of the variable
``sys.version``.
.. c:function:: void PySys_SetArgvEx(int argc, wchar_t **argv, int updatepath)
.. index::
single: main()
single: Py_FatalError()
single: argv (in module sys)
This API is kept for backward compatibility: setting
:c:member:`PyConfig.argv`, :c:member:`PyConfig.parse_argv` and
:c:member:`PyConfig.safe_path` should be used instead, see :ref:`Python
Initialization Configuration <init-config>`.
Set :data:`sys.argv` based on *argc* and *argv*. These parameters are
similar to those passed to the program's :c:func:`main` function with the
difference that the first entry should refer to the script file to be
executed rather than the executable hosting the Python interpreter. If there
isn't a script that will be run, the first entry in *argv* can be an empty
string. If this function fails to initialize :data:`sys.argv`, a fatal
condition is signalled using :c:func:`Py_FatalError`.
If *updatepath* is zero, this is all the function does. If *updatepath*
is non-zero, the function also modifies :data:`sys.path` according to the
following algorithm:
- If the name of an existing script is passed in ``argv[0]``, the absolute
path of the directory where the script is located is prepended to
:data:`sys.path`.
- Otherwise (that is, if *argc* is ``0`` or ``argv[0]`` doesn't point
to an existing file name), an empty string is prepended to
:data:`sys.path`, which is the same as prepending the current working
directory (``"."``).
Use :c:func:`Py_DecodeLocale` to decode a bytes string to get a
:c:expr:`wchar_t*` string.
See also :c:member:`PyConfig.orig_argv` and :c:member:`PyConfig.argv`
members of the :ref:`Python Initialization Configuration <init-config>`.
.. note::
It is recommended that applications embedding the Python interpreter
for purposes other than executing a single script pass ``0`` as *updatepath*,
and update :data:`sys.path` themselves if desired.
See :cve:`2008-5983`.
On versions before 3.1.3, you can achieve the same effect by manually
popping the first :data:`sys.path` element after having called
:c:func:`PySys_SetArgv`, for example using::
PyRun_SimpleString("import sys; sys.path.pop(0)\n");
.. versionadded:: 3.1.3
.. deprecated-removed:: 3.11 3.15
.. c:function:: void PySys_SetArgv(int argc, wchar_t **argv)
This API is kept for backward compatibility: setting
:c:member:`PyConfig.argv` and :c:member:`PyConfig.parse_argv` should be used
instead, see :ref:`Python Initialization Configuration <init-config>`.
This function works like :c:func:`PySys_SetArgvEx` with *updatepath* set
to ``1`` unless the :program:`python` interpreter was started with the
:option:`-I`.
Use :c:func:`Py_DecodeLocale` to decode a bytes string to get a
:c:expr:`wchar_t*` string.
See also :c:member:`PyConfig.orig_argv` and :c:member:`PyConfig.argv`
members of the :ref:`Python Initialization Configuration <init-config>`.
.. versionchanged:: 3.4 The *updatepath* value depends on :option:`-I`.
.. deprecated-removed:: 3.11 3.15
.. c:function:: void Py_SetPythonHome(const wchar_t *home)
This API is kept for backward compatibility: setting
:c:member:`PyConfig.home` should be used instead, see :ref:`Python
Initialization Configuration <init-config>`.
Set the default "home" directory, that is, the location of the standard
Python libraries. See :envvar:`PYTHONHOME` for the meaning of the
argument string.
The argument should point to a zero-terminated character string in static
storage whose contents will not change for the duration of the program's
execution. No code in the Python interpreter will change the contents of
this storage.
Use :c:func:`Py_DecodeLocale` to decode a bytes string to get a
:c:expr:`wchar_t*` string.
.. deprecated-removed:: 3.11 3.15

537
Doc/c-api/intro.rst
View file

@ -123,6 +123,7 @@ System includes
* ``<limits.h>``
* ``<math.h>``
* ``<stdarg.h>``
* ``<string.h>``
* ``<wchar.h>``
* ``<sys/types.h>`` (if present)
@ -138,7 +139,6 @@ System includes
* ``<errno.h>``
* ``<stdio.h>``
* ``<stdlib.h>``
* ``<string.h>``
.. note::
@ -156,28 +156,126 @@ defined closer to where they are useful (for example, :c:macro:`Py_RETURN_NONE`,
Others of a more general utility are defined here. This is not necessarily a
complete listing.
.. c:macro:: Py_CAN_START_THREADS
If this macro is defined, then the current system is able to start threads.
Currently, all systems supported by CPython (per :pep:`11`), with the
exception of some WebAssembly platforms, support starting threads.
.. versionadded:: 3.13
.. c:macro:: Py_GETENV(s)
Like :samp:`getenv({s})`, but returns ``NULL`` if :option:`-E` was passed
on the command line (see :c:member:`PyConfig.use_environment`).
Docstring macros
----------------
.. c:macro:: PyDoc_STRVAR(name, str)
Creates a variable with name *name* that can be used in docstrings.
If Python is built without docstrings (:option:`--without-doc-strings`),
the value will be an empty string.
Example::
PyDoc_STRVAR(pop_doc, "Remove and return the rightmost element.");
static PyMethodDef deque_methods[] = {
// ...
{"pop", (PyCFunction)deque_pop, METH_NOARGS, pop_doc},
// ...
}
Expands to :samp:`PyDoc_VAR({name}) = PyDoc_STR({str})`.
.. c:macro:: PyDoc_STR(str)
Expands to the given input string, or an empty string
if docstrings are disabled (:option:`--without-doc-strings`).
Example::
static PyMethodDef pysqlite_row_methods[] = {
{"keys", (PyCFunction)pysqlite_row_keys, METH_NOARGS,
PyDoc_STR("Returns the keys of the row.")},
{NULL, NULL}
};
.. c:macro:: PyDoc_VAR(name)
Declares a static character array variable with the given *name*.
Expands to :samp:`static const char {name}[]`
For example::
PyDoc_VAR(python_doc) = PyDoc_STR(
"A genus of constricting snakes in the Pythonidae family native "
"to the tropics and subtropics of the Eastern Hemisphere.");
General utility macros
----------------------
The following macros are for common tasks not specific to Python.
.. c:macro:: Py_UNUSED(arg)
Use this for unused arguments in a function definition to silence compiler
warnings. Example: ``int func(int a, int Py_UNUSED(b)) { return a; }``.
.. versionadded:: 3.4
.. c:macro:: Py_GCC_ATTRIBUTE(name)
Use a GCC attribute *name*, hiding it from compilers that don't support GCC
attributes (such as MSVC).
This expands to :samp:`__attribute__(({name)})` on a GCC compiler,
and expands to nothing on compilers that don't support GCC attributes.
Numeric utilities
^^^^^^^^^^^^^^^^^
.. c:macro:: Py_ABS(x)
Return the absolute value of ``x``.
The argument may be evaluated more than once.
Consequently, do not pass an expression with side-effects directly
to this macro.
If the result cannot be represented (for example, if ``x`` has
:c:macro:`!INT_MIN` value for :c:expr:`int` type), the behavior is
undefined.
Corresponds roughly to :samp:`(({x}) < 0 ? -({x}) : ({x}))`
.. versionadded:: 3.3
.. c:macro:: Py_ALIGNED(num)
.. c:macro:: Py_MAX(x, y)
Py_MIN(x, y)
Specify alignment to *num* bytes on compilers that support it.
Return the larger or smaller of the arguments, respectively.
Consider using the C11 standard ``_Alignas`` specifier over this macro.
Any arguments may be evaluated more than once.
Consequently, do not pass an expression with side-effects directly
to this macro.
:c:macro:`!Py_MAX` corresponds roughly to
:samp:`((({x}) > ({y})) ? ({x}) : ({y}))`.
.. versionadded:: 3.3
.. c:macro:: Py_ARITHMETIC_RIGHT_SHIFT(type, integer, positions)
Similar to ``integer >> positions``, but forces sign extension, as the C
standard does not define whether a right-shift of a signed integer will
perform sign extension or a zero-fill.
Similar to :samp:`{integer} >> {positions}`, but forces sign extension,
as the C standard does not define whether a right-shift of a signed
integer will perform sign extension or a zero-fill.
*integer* should be any signed integer type.
*positions* is the number of positions to shift to the right.
@ -196,170 +294,14 @@ complete listing.
which ``unsigned type`` is legal. As a result, *type* is no longer
used.
.. c:macro:: Py_ALWAYS_INLINE
Ask the compiler to always inline a static inline function. The compiler can
ignore it and decide to not inline the function.
It can be used to inline performance critical static inline functions when
building Python in debug mode with function inlining disabled. For example,
MSC disables function inlining when building in debug mode.
Marking blindly a static inline function with Py_ALWAYS_INLINE can result in
worse performances (due to increased code size for example). The compiler is
usually smarter than the developer for the cost/benefit analysis.
If Python is :ref:`built in debug mode <debug-build>` (if the :c:macro:`Py_DEBUG`
macro is defined), the :c:macro:`Py_ALWAYS_INLINE` macro does nothing.
It must be specified before the function return type. Usage::
static inline Py_ALWAYS_INLINE int random(void) { return 4; }
.. versionadded:: 3.11
.. c:macro:: Py_CAN_START_THREADS
If this macro is defined, then the current system is able to start threads.
Currently, all systems supported by CPython (per :pep:`11`), with the
exception of some WebAssembly platforms, support starting threads.
.. versionadded:: 3.13
.. c:macro:: Py_CHARMASK(c)
Argument must be a character or an integer in the range [-128, 127] or [0,
255]. This macro returns ``c`` cast to an ``unsigned char``.
.. c:macro:: Py_DEPRECATED(version)
Use this for deprecated declarations. The macro must be placed before the
symbol name.
Example::
Py_DEPRECATED(3.8) PyAPI_FUNC(int) Py_OldFunction(void);
.. versionchanged:: 3.8
MSVC support was added.
.. c:macro:: Py_FORCE_EXPANSION(X)
This is equivalent to ``X``, which is useful for token-pasting in
macros, as macro expansions in *X* are forcefully evaluated by the
preprocessor.
.. c:macro:: Py_GCC_ATTRIBUTE(name)
Use a GCC attribute *name*, hiding it from compilers that don't support GCC
attributes (such as MSVC).
This expands to ``__attribute__((name))`` on a GCC compiler, and expands
to nothing on compilers that don't support GCC attributes.
.. c:macro:: Py_GETENV(s)
Like ``getenv(s)``, but returns ``NULL`` if :option:`-E` was passed on the
command line (see :c:member:`PyConfig.use_environment`).
.. c:macro:: Py_LL(number)
Use *number* as a ``long long`` integer literal.
This usally expands to *number* followed by ``LL``, but will expand to some
compiler-specific suffixes (such as ``I64``) on older compilers.
In modern versions of Python, this macro is not very useful, as C99 and
later require the ``LL`` suffix to be valid for an integer.
.. c:macro:: Py_LOCAL(type)
Declare a function returning the specified *type* using a fast-calling
qualifier for functions that are local to the current file.
Semantically, this is equivalent to ``static type``.
.. c:macro:: Py_LOCAL_INLINE(type)
Equivalent to :c:macro:`Py_LOCAL` but additionally requests the function
be inlined.
.. c:macro:: Py_LOCAL_SYMBOL
Macro used to declare a symbol as local to the shared library (hidden).
On supported platforms, it ensures the symbol is not exported.
On compatible versions of GCC/Clang, it
expands to ``__attribute__((visibility("hidden")))``.
.. c:macro:: Py_MAX(x, y)
Return the maximum value between ``x`` and ``y``.
.. versionadded:: 3.3
.. c:macro:: Py_MEMBER_SIZE(type, member)
Return the size of a structure (``type``) ``member`` in bytes.
.. versionadded:: 3.6
.. c:macro:: Py_MEMCPY(dest, src, n)
This is a :term:`soft deprecated` alias to :c:func:`!memcpy`.
Use :c:func:`!memcpy` directly instead.
.. deprecated:: 3.14
The macro is :term:`soft deprecated`.
.. c:macro:: Py_MIN(x, y)
Return the minimum value between ``x`` and ``y``.
.. versionadded:: 3.3
.. c:macro:: Py_NO_INLINE
Disable inlining on a function. For example, it reduces the C stack
consumption: useful on LTO+PGO builds which heavily inline code (see
:issue:`33720`).
Usage::
Py_NO_INLINE static int random(void) { return 4; }
.. versionadded:: 3.11
.. c:macro:: Py_SAFE_DOWNCAST(value, larger, smaller)
Cast *value* to type *smaller* from type *larger*, validating that no
information was lost.
On release builds of Python, this is roughly equivalent to
``(smaller) value`` (in C++, ``static_cast<smaller>(value)`` will be
used instead).
On debug builds (implying that :c:macro:`Py_DEBUG` is defined), this asserts
that no information was lost with the cast from *larger* to *smaller*.
*value*, *larger*, and *smaller* may all be evaluated more than once in the
expression; consequently, do not pass an expression with side-effects directly to
this macro.
.. c:macro:: Py_STRINGIFY(x)
Convert ``x`` to a C string. E.g. ``Py_STRINGIFY(123)`` returns
``"123"``.
.. versionadded:: 3.4
.. c:macro:: Py_ULL(number)
Similar to :c:macro:`Py_LL`, but *number* will be an ``unsigned long long``
literal instead. This is done by appending ``U`` to the result of ``Py_LL``.
In modern versions of Python, this macro is not very useful, as C99 and
later require the ``ULL``/``LLU`` suffixes to be valid for an integer.
Assertion utilities
^^^^^^^^^^^^^^^^^^^
.. c:macro:: Py_UNREACHABLE()
@ -372,8 +314,11 @@ complete listing.
avoids a warning about unreachable code. For example, the macro is
implemented with ``__builtin_unreachable()`` on GCC in release mode.
A use for ``Py_UNREACHABLE()`` is following a call a function that
never returns but that is not declared :c:macro:`_Py_NO_RETURN`.
In debug mode, and on unsupported compilers, the macro expands to a call to
:c:func:`Py_FatalError`.
A use for ``Py_UNREACHABLE()`` is following a call to a function that
never returns but that is not declared ``_Noreturn``.
If a code path is very unlikely code but can be reached under exceptional
case, this macro must not be used. For example, under low memory condition
@ -383,18 +328,29 @@ complete listing.
.. versionadded:: 3.7
.. c:macro:: Py_UNUSED(arg)
.. c:macro:: Py_SAFE_DOWNCAST(value, larger, smaller)
Use this for unused arguments in a function definition to silence compiler
warnings. Example: ``int func(int a, int Py_UNUSED(b)) { return a; }``.
Cast *value* to type *smaller* from type *larger*, validating that no
information was lost.
.. versionadded:: 3.4
On release builds of Python, this is roughly equivalent to
:samp:`(({smaller}) {value})`
(in C++, :samp:`static_cast<{smaller}>({value})` will be used instead).
On debug builds (implying that :c:macro:`Py_DEBUG` is defined), this asserts
that no information was lost with the cast from *larger* to *smaller*.
*value*, *larger*, and *smaller* may all be evaluated more than once in the
expression; consequently, do not pass an expression with side-effects
directly to this macro.
.. c:macro:: Py_BUILD_ASSERT(cond)
Asserts a compile-time condition *cond*, as a statement.
The build will fail if the condition is false or cannot be evaluated at compile time.
Corresponds roughly to :samp:`static_assert({cond})` on C23 and above.
For example::
Py_BUILD_ASSERT(sizeof(PyTime_t) == sizeof(int64_t));
@ -413,48 +369,9 @@ complete listing.
.. versionadded:: 3.3
.. c:macro:: PyDoc_STRVAR(name, str)
Creates a variable with name *name* that can be used in docstrings.
If Python is built without docstrings, the value will be empty.
Use :c:macro:`PyDoc_STRVAR` for docstrings to support building
Python without docstrings, as specified in :pep:`7`.
Example::
PyDoc_STRVAR(pop_doc, "Remove and return the rightmost element.");
static PyMethodDef deque_methods[] = {
// ...
{"pop", (PyCFunction)deque_pop, METH_NOARGS, pop_doc},
// ...
}
.. c:macro:: PyDoc_STR(str)
Creates a docstring for the given input string or an empty string
if docstrings are disabled.
Use :c:macro:`PyDoc_STR` in specifying docstrings to support
building Python without docstrings, as specified in :pep:`7`.
Example::
static PyMethodDef pysqlite_row_methods[] = {
{"keys", (PyCFunction)pysqlite_row_keys, METH_NOARGS,
PyDoc_STR("Returns the keys of the row.")},
{NULL, NULL}
};
.. c:macro:: PyDoc_VAR(name)
Declares a static character array variable with the given name *name*.
For example::
PyDoc_VAR(python_doc) = PyDoc_STR("A genus of constricting snakes in the Pythonidae family native "
"to the tropics and subtropics of the Eastern Hemisphere.");
Type size utilities
^^^^^^^^^^^^^^^^^^^
.. c:macro:: Py_ARRAY_LENGTH(array)
@ -469,6 +386,110 @@ complete listing.
sizeof(array) / sizeof((array)[0])
.. c:macro:: Py_MEMBER_SIZE(type, member)
Return the size of a structure (*type*) *member* in bytes.
Corresponds roughly to :samp:`sizeof((({type} *)NULL)->{member})`.
.. versionadded:: 3.6
Macro definition utilities
^^^^^^^^^^^^^^^^^^^^^^^^^^
.. c:macro:: Py_FORCE_EXPANSION(X)
This is equivalent to :samp:`{X}`, which is useful for token-pasting in
macros, as macro expansions in *X* are forcefully evaluated by the
preprocessor.
.. c:macro:: Py_STRINGIFY(x)
Convert ``x`` to a C string. For example, ``Py_STRINGIFY(123)`` returns
``"123"``.
.. versionadded:: 3.4
Declaration utilities
---------------------
The following macros can be used in declarations.
They are most useful for defining the C API itself, and have limited use
for extension authors.
Most of them expand to compiler-specific spellings of common extensions
to the C language.
.. c:macro:: Py_ALWAYS_INLINE
Ask the compiler to always inline a static inline function. The compiler can
ignore it and decide to not inline the function.
Corresponds to ``always_inline`` attribute in GCC and ``__forceinline``
in MSVC.
It can be used to inline performance critical static inline functions when
building Python in debug mode with function inlining disabled. For example,
MSC disables function inlining when building in debug mode.
Marking blindly a static inline function with Py_ALWAYS_INLINE can result in
worse performances (due to increased code size for example). The compiler is
usually smarter than the developer for the cost/benefit analysis.
If Python is :ref:`built in debug mode <debug-build>` (if the :c:macro:`Py_DEBUG`
macro is defined), the :c:macro:`Py_ALWAYS_INLINE` macro does nothing.
It must be specified before the function return type. Usage::
static inline Py_ALWAYS_INLINE int random(void) { return 4; }
.. versionadded:: 3.11
.. c:macro:: Py_NO_INLINE
Disable inlining on a function. For example, it reduces the C stack
consumption: useful on LTO+PGO builds which heavily inline code (see
:issue:`33720`).
Corresponds to the ``noinline`` attribute/specification on GCC and MSVC.
Usage::
Py_NO_INLINE static int random(void) { return 4; }
.. versionadded:: 3.11
.. c:macro:: Py_DEPRECATED(version)
Use this to declare APIs that were deprecated in a specific CPython version.
The macro must be placed before the symbol name.
Example::
Py_DEPRECATED(3.8) PyAPI_FUNC(int) Py_OldFunction(void);
.. versionchanged:: 3.8
MSVC support was added.
.. c:macro:: Py_LOCAL(type)
Declare a function returning the specified *type* using a fast-calling
qualifier for functions that are local to the current file.
Semantically, this is equivalent to :samp:`static {type}`.
.. c:macro:: Py_LOCAL_INLINE(type)
Equivalent to :c:macro:`Py_LOCAL` but additionally requests the function
be inlined.
.. c:macro:: Py_LOCAL_SYMBOL
Macro used to declare a symbol as local to the shared library (hidden).
On supported platforms, it ensures the symbol is not exported.
On compatible versions of GCC/Clang, it
expands to ``__attribute__((visibility("hidden")))``.
.. c:macro:: Py_EXPORTED_SYMBOL
@ -501,16 +522,104 @@ complete listing.
This macro is intended for defining CPython's C API itself;
extension modules should not use it for their own symbols.
Outdated macros
---------------
The following :term:`soft deprecated` macros have been used to features that
have been standardized in C11 (or previous standards).
.. c:macro:: Py_ALIGNED(num)
On some GCC-like compilers, specify alignment to *num* bytes.
This does nothing on other compilers.
Use the standard ``alignas`` specifier rather than this macro.
.. soft-deprecated:: 3.15
.. c:macro:: PY_FORMAT_SIZE_T
The :c:func:`printf` formatting modifier for :c:type:`size_t`.
Use ``"z"`` directly instead.
.. soft-deprecated:: 3.15
.. c:macro:: Py_LL(number)
Py_ULL(number)
Use *number* as a ``long long`` or ``unsigned long long`` integer literal,
respectively.
Expands to *number* followed by ``LL`` or ``LLU``, respectively, but will
expand to some compiler-specific suffixes on some older compilers.
Consider using the C99 standard suffixes ``LL`` and ``LLU`` directly.
.. soft-deprecated:: 3.15
.. c:macro:: PY_LONG_LONG
PY_INT32_T
PY_UINT32_T
PY_INT64_T
PY_UINT64_T
Aliases for the types :c:type:`!long long`, :c:type:`!int32_t`,
:c:type:`!uint32_t`. :c:type:`!int64_t` and :c:type:`!uint64_t`,
respectively.
Historically, these types needed compiler-specific extensions.
.. soft-deprecated:: 3.15
.. c:macro:: PY_LLONG_MIN
PY_LLONG_MAX
PY_ULLONG_MAX
PY_SIZE_MAX
Aliases for the values :c:macro:`!LLONG_MIN`, :c:macro:`!LLONG_MAX`,
:c:macro:`!ULLONG_MAX`, and :c:macro:`!SIZE_MAX`, respectively.
Use these standard names instead.
The required header, ``<limits.h>``,
:ref:`is included <capi-system-includes>` in ``Python.h``.
.. soft-deprecated:: 3.15
.. c:macro:: Py_MEMCPY(dest, src, n)
This is an alias to :c:func:`!memcpy`.
.. soft-deprecated:: 3.14
Use :c:func:`!memcpy` directly instead.
.. c:macro:: Py_UNICODE_SIZE
Size of the :c:type:`!wchar_t` type.
Use ``sizeof(wchar_t)`` or ``WCHAR_WIDTH/8`` instead.
The required header for the latter, ``<limits.h>``,
:ref:`is included <capi-system-includes>` in ``Python.h``.
.. soft-deprecated:: 3.15
.. c:macro:: Py_UNICODE_WIDE
Defined if ``wchar_t`` can hold a Unicode character (UCS-4).
Use ``sizeof(wchar_t) >= 4`` instead
.. soft-deprecated:: 3.15
.. c:macro:: Py_VA_COPY
This is a :term:`soft deprecated` alias to the C99-standard ``va_copy``
function.
This is an alias to the C99-standard ``va_copy`` function.
Historically, this would use a compiler-specific method to copy a ``va_list``.
.. versionchanged:: 3.6
This is now an alias to ``va_copy``.
.. soft-deprecated:: 3.15
.. _api-objects:

44
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@ -74,11 +74,25 @@ List Objects
Like :c:func:`PyList_GetItemRef`, but returns a
:term:`borrowed reference` instead of a :term:`strong reference`.
.. note::
In the :term:`free-threaded build`, the returned
:term:`borrowed reference` may become invalid if another thread modifies
the list concurrently. Prefer :c:func:`PyList_GetItemRef`, which returns
a :term:`strong reference`.
.. c:function:: PyObject* PyList_GET_ITEM(PyObject *list, Py_ssize_t i)
Similar to :c:func:`PyList_GetItem`, but without error checking.
.. note::
In the :term:`free-threaded build`, the returned
:term:`borrowed reference` may become invalid if another thread modifies
the list concurrently. Prefer :c:func:`PyList_GetItemRef`, which returns
a :term:`strong reference`.
.. c:function:: int PyList_SetItem(PyObject *list, Py_ssize_t index, PyObject *item)
@ -108,6 +122,14 @@ List Objects
is being replaced; any reference in *list* at position *i* will be
leaked.
.. note::
In the :term:`free-threaded build`, this macro has no internal
synchronization. It is normally only used to fill in new lists where no
other thread has a reference to the list. If the list may be shared,
use :c:func:`PyList_SetItem` instead, which uses a :term:`per-object
lock`.
.. c:function:: int PyList_Insert(PyObject *list, Py_ssize_t index, PyObject *item)
@ -138,6 +160,12 @@ List Objects
Return ``0`` on success, ``-1`` on failure. Indexing from the end of the
list is not supported.
.. note::
In the :term:`free-threaded build`, when *itemlist* is a :class:`list`,
both *list* and *itemlist* are locked for the duration of the operation.
For other iterables (or ``NULL``), only *list* is locked.
.. c:function:: int PyList_Extend(PyObject *list, PyObject *iterable)
@ -150,6 +178,14 @@ List Objects
.. versionadded:: 3.13
.. note::
In the :term:`free-threaded build`, when *iterable* is a :class:`list`,
:class:`set`, :class:`dict`, or dict view, both *list* and *iterable*
(or its underlying dict) are locked for the duration of the operation.
For other iterables, only *list* is locked; *iterable* may be
concurrently modified by another thread.
.. c:function:: int PyList_Clear(PyObject *list)
@ -168,6 +204,14 @@ List Objects
Sort the items of *list* in place. Return ``0`` on success, ``-1`` on
failure. This is equivalent to ``list.sort()``.
.. note::
In the :term:`free-threaded build`, element comparison via
:meth:`~object.__lt__` can execute arbitrary Python code, during which
the :term:`per-object lock` may be temporarily released. For built-in
types (:class:`str`, :class:`int`, :class:`float`), the lock is not
released during comparison.
.. c:function:: int PyList_Reverse(PyObject *list)

4
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@ -197,12 +197,10 @@ distinguished from a number. Use :c:func:`PyErr_Occurred` to disambiguate.
.. c:function:: long PyLong_AS_LONG(PyObject *obj)
A :term:`soft deprecated` alias.
Exactly equivalent to the preferred ``PyLong_AsLong``. In particular,
it can fail with :exc:`OverflowError` or another exception.
.. deprecated:: 3.14
The function is soft deprecated.
.. soft-deprecated:: 3.14
.. c:function:: int PyLong_AsInt(PyObject *obj)

65
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@ -7,10 +7,6 @@
Memory Management
*****************
.. sectionauthor:: Vladimir Marangozov <Vladimir.Marangozov@inrialpes.fr>
.. _memoryoverview:
Overview
@ -208,8 +204,11 @@ The following function sets, modeled after the ANSI C standard, but specifying
behavior when requesting zero bytes, are available for allocating and releasing
memory from the Python heap.
The :ref:`default memory allocator <default-memory-allocators>` uses the
:ref:`pymalloc memory allocator <pymalloc>`.
In the GIL-enabled build (default build) the
:ref:`default memory allocator <default-memory-allocators>` uses the
:ref:`pymalloc memory allocator <pymalloc>`, whereas in the
:term:`free-threaded build`, the default is the
:ref:`mimalloc memory allocator <mimalloc>` instead.
.. warning::
@ -219,6 +218,11 @@ The :ref:`default memory allocator <default-memory-allocators>` uses the
The default allocator is now pymalloc instead of system :c:func:`malloc`.
.. versionchanged:: 3.13
In the :term:`free-threaded <free threading>` build, the default allocator
is now :ref:`mimalloc <mimalloc>`.
.. c:function:: void* PyMem_Malloc(size_t n)
Allocates *n* bytes and returns a pointer of type :c:expr:`void*` to the
@ -344,7 +348,9 @@ memory from the Python heap.
the :ref:`Customize Memory Allocators <customize-memory-allocators>` section.
The :ref:`default object allocator <default-memory-allocators>` uses the
:ref:`pymalloc memory allocator <pymalloc>`.
:ref:`pymalloc memory allocator <pymalloc>`. In the
:term:`free-threaded <free threading>` build, the default is the
:ref:`mimalloc memory allocator <mimalloc>` instead.
.. warning::
@ -424,14 +430,16 @@ Default Memory Allocators
Default memory allocators:
=============================== ==================== ================== ===================== ====================
Configuration Name PyMem_RawMalloc PyMem_Malloc PyObject_Malloc
=============================== ==================== ================== ===================== ====================
Release build ``"pymalloc"`` ``malloc`` ``pymalloc`` ``pymalloc``
Debug build ``"pymalloc_debug"`` ``malloc`` + debug ``pymalloc`` + debug ``pymalloc`` + debug
Release build, without pymalloc ``"malloc"`` ``malloc`` ``malloc`` ``malloc``
Debug build, without pymalloc ``"malloc_debug"`` ``malloc`` + debug ``malloc`` + debug ``malloc`` + debug
=============================== ==================== ================== ===================== ====================
=================================== ======================= ==================== ====================== ======================
Configuration Name PyMem_RawMalloc PyMem_Malloc PyObject_Malloc
=================================== ======================= ==================== ====================== ======================
Release build ``"pymalloc"`` ``malloc`` ``pymalloc`` ``pymalloc``
Debug build ``"pymalloc_debug"`` ``malloc`` + debug ``pymalloc`` + debug ``pymalloc`` + debug
Release build, without pymalloc ``"malloc"`` ``malloc`` ``malloc`` ``malloc``
Debug build, without pymalloc ``"malloc_debug"`` ``malloc`` + debug ``malloc`` + debug ``malloc`` + debug
Free-threaded build ``"mimalloc"`` ``mimalloc`` ``mimalloc`` ``mimalloc``
Free-threaded debug build ``"mimalloc_debug"`` ``mimalloc`` + debug ``mimalloc`` + debug ``mimalloc`` + debug
=================================== ======================= ==================== ====================== ======================
Legend:
@ -439,8 +447,7 @@ Legend:
* ``malloc``: system allocators from the standard C library, C functions:
:c:func:`malloc`, :c:func:`calloc`, :c:func:`realloc` and :c:func:`free`.
* ``pymalloc``: :ref:`pymalloc memory allocator <pymalloc>`.
* ``mimalloc``: :ref:`mimalloc memory allocator <mimalloc>`. The pymalloc
allocator will be used if mimalloc support isn't available.
* ``mimalloc``: :ref:`mimalloc memory allocator <mimalloc>`.
* "+ debug": with :ref:`debug hooks on the Python memory allocators
<pymem-debug-hooks>`.
* "Debug build": :ref:`Python build in debug mode <debug-build>`.
@ -737,9 +744,27 @@ The mimalloc allocator
.. versionadded:: 3.13
Python supports the mimalloc allocator when the underlying platform support is available.
mimalloc "is a general purpose allocator with excellent performance characteristics.
Initially developed by Daan Leijen for the runtime systems of the Koka and Lean languages."
Python supports the `mimalloc <https://github.com/microsoft/mimalloc/>`__
allocator when the underlying platform support is available.
mimalloc is a general purpose allocator with excellent performance
characteristics, initially developed by Daan Leijen for the runtime systems
of the Koka and Lean languages.
Unlike :ref:`pymalloc <pymalloc>`, which is optimized for small objects (512
bytes or fewer), mimalloc handles allocations of any size.
In the :term:`free-threaded <free threading>` build, mimalloc is the default
and **required** allocator for the :c:macro:`PYMEM_DOMAIN_MEM` and
:c:macro:`PYMEM_DOMAIN_OBJ` domains. It cannot be disabled in free-threaded
builds. The free-threaded build uses per-thread mimalloc heaps, which allows
allocation and deallocation to proceed without locking in most cases.
In the default (non-free-threaded) build, mimalloc is available but not the
default allocator. It can be selected at runtime using
:envvar:`PYTHONMALLOC`\ ``=mimalloc`` (or ``mimalloc_debug`` to include
:ref:`debug hooks <pymem-debug-hooks>`). It can be disabled at build time
using the :option:`--without-mimalloc` configure option, but this option
cannot be combined with :option:`--disable-gil`.
tracemalloc C API
=================

38
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@ -230,6 +230,9 @@ Feature slots
When creating a module, Python checks the value of this slot
using :c:func:`PyABIInfo_Check`.
This slot is required, except for modules created from
:c:struct:`PyModuleDef`.
.. versionadded:: 3.15
.. c:macro:: Py_mod_multiple_interpreters
@ -620,9 +623,9 @@ rather than from an extension's :ref:`export hook <extension-export-hook>`.
and the :py:class:`~importlib.machinery.ModuleSpec` *spec*.
The *slots* argument must point to an array of :c:type:`PyModuleDef_Slot`
structures, terminated by an entry slot with slot ID of 0
structures, terminated by an entry with slot ID of 0
(typically written as ``{0}`` or ``{0, NULL}`` in C).
The *slots* argument may not be ``NULL``.
The array must include a :c:data:`Py_mod_abi` entry.
The *spec* argument may be any ``ModuleSpec``-like object, as described
in :c:macro:`Py_mod_create` documentation.
@ -682,6 +685,12 @@ remove it.
Usually, there is only one variable of this type for each extension module
defined this way.
The struct, including all members, is part of the
:ref:`Stable ABI <stable-abi>` for non-free-threaded builds (``abi3``).
In the Stable ABI for free-threaded builds (``abi3t``),
this struct is opaque, and unusable in practice; see :ref:`pymoduledef_slot`
for a replacement.
.. c:member:: PyModuleDef_Base m_base
Always initialize this member to :c:macro:`PyModuleDef_HEAD_INIT`:
@ -692,6 +701,11 @@ remove it.
The type of :c:member:`!PyModuleDef.m_base`.
The struct is part of the :ref:`Stable ABI <stable-abi>` for
non-free-threaded builds (``abi3``).
In the Stable ABI for Free-Threaded Builds
(``abi3t``), this struct is opaque, and unusable in practice.
.. c:macro:: PyModuleDef_HEAD_INIT
The required initial value for :c:member:`!PyModuleDef.m_base`.
@ -725,10 +739,11 @@ remove it.
An array of additional slots, terminated by a ``{0, NULL}`` entry.
This array may not contain slots corresponding to :c:type:`PyModuleDef`
members.
For example, you cannot use :c:macro:`Py_mod_name` in :c:member:`!m_slots`;
the module name must be given as :c:member:`PyModuleDef.m_name`.
If the array contains slots corresponding to :c:type:`PyModuleDef`
members, the values must match.
For example, if you use :c:macro:`Py_mod_name` in :c:member:`!m_slots`,
:c:member:`PyModuleDef.m_name` must be set to the same pointer
(not just an equal string).
.. versionchanged:: 3.5
@ -751,7 +766,12 @@ remove it.
.. versionchanged:: 3.9
:c:member:`m_traverse`, :c:member:`m_clear` and :c:member:`m_free`
functions are longer called before the module state is allocated.
functions are no longer called before the module state is allocated.
.. c:var:: PyTypeObject PyModuleDef_Type
The type of ``PyModuleDef`` objects.
.. _moduledef-dynamic:
@ -945,9 +965,7 @@ or code that creates modules dynamically.
// PyModule_AddObject() stole a reference to obj:
// Py_XDECREF(obj) is not needed here.
.. deprecated:: 3.13
:c:func:`PyModule_AddObject` is :term:`soft deprecated`.
.. soft-deprecated:: 3.13
.. c:function:: int PyModule_AddIntConstant(PyObject *module, const char *name, long value)

4
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@ -205,6 +205,4 @@ would typically correspond to a Python function.
.. versionadded:: 3.13
.. deprecated:: 3.14
This function is :term:`soft deprecated`.
.. soft-deprecated:: 3.14

25
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@ -363,6 +363,8 @@ Object Protocol
representation on success, ``NULL`` on failure. This is the equivalent of the
Python expression ``repr(o)``. Called by the :func:`repr` built-in function.
If argument is ``NULL``, return the string ``'<NULL>'``.
.. versionchanged:: 3.4
This function now includes a debug assertion to help ensure that it
does not silently discard an active exception.
@ -377,6 +379,8 @@ Object Protocol
a string similar to that returned by :c:func:`PyObject_Repr` in Python 2.
Called by the :func:`ascii` built-in function.
If argument is ``NULL``, return the string ``'<NULL>'``.
.. index:: string; PyObject_Str (C function)
@ -387,6 +391,8 @@ Object Protocol
Python expression ``str(o)``. Called by the :func:`str` built-in function
and, therefore, by the :func:`print` function.
If argument is ``NULL``, return the string ``'<NULL>'``.
.. versionchanged:: 3.4
This function now includes a debug assertion to help ensure that it
does not silently discard an active exception.
@ -402,6 +408,8 @@ Object Protocol
a TypeError is raised when *o* is an integer instead of a zero-initialized
bytes object.
If argument is ``NULL``, return the :class:`bytes` object ``b'<NULL>'``.
.. c:function:: int PyObject_IsSubclass(PyObject *derived, PyObject *cls)
@ -801,3 +809,20 @@ Object Protocol
cannot fail.
.. versionadded:: 3.14
.. c:function:: int PyUnstable_SetImmortal(PyObject *op)
Marks the object *op* :term:`immortal`. The argument should be uniquely referenced by
the calling thread. This is intended to be used for reducing reference counting contention
in the :term:`free-threaded build` for objects which are shared across threads.
This is a one-way process: objects can only be made immortal; they cannot be
made mortal once again. Immortal objects do not participate in reference counting
and will never be garbage collected. If the object is GC-tracked, it is untracked.
This function is intended to be used soon after *op* is created, by the code that
creates it, such as in the object's :c:member:`~PyTypeObject.tp_new` slot.
Returns 1 if the object was made immortal and returns 0 if it was not.
This function cannot fail.
.. versionadded:: 3.15

239
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@ -0,0 +1,239 @@
.. highlight:: c
.. _profiling:
Profiling and tracing
=====================
The Python interpreter provides some low-level support for attaching profiling
and execution tracing facilities. These are used for profiling, debugging, and
coverage analysis tools.
This C interface allows the profiling or tracing code to avoid the overhead of
calling through Python-level callable objects, making a direct C function call
instead. The essential attributes of the facility have not changed; the
interface allows trace functions to be installed per-thread, and the basic
events reported to the trace function are the same as had been reported to the
Python-level trace functions in previous versions.
.. c:type:: int (*Py_tracefunc)(PyObject *obj, PyFrameObject *frame, int what, PyObject *arg)
The type of the trace function registered using :c:func:`PyEval_SetProfile` and
:c:func:`PyEval_SetTrace`. The first parameter is the object passed to the
registration function as *obj*, *frame* is the frame object to which the event
pertains, *what* is one of the constants :c:data:`PyTrace_CALL`,
:c:data:`PyTrace_EXCEPTION`, :c:data:`PyTrace_LINE`, :c:data:`PyTrace_RETURN`,
:c:data:`PyTrace_C_CALL`, :c:data:`PyTrace_C_EXCEPTION`, :c:data:`PyTrace_C_RETURN`,
or :c:data:`PyTrace_OPCODE`, and *arg* depends on the value of *what*:
+-------------------------------+----------------------------------------+
| Value of *what* | Meaning of *arg* |
+===============================+========================================+
| :c:data:`PyTrace_CALL` | Always :c:data:`Py_None`. |
+-------------------------------+----------------------------------------+
| :c:data:`PyTrace_EXCEPTION` | Exception information as returned by |
| | :func:`sys.exc_info`. |
+-------------------------------+----------------------------------------+
| :c:data:`PyTrace_LINE` | Always :c:data:`Py_None`. |
+-------------------------------+----------------------------------------+
| :c:data:`PyTrace_RETURN` | Value being returned to the caller, |
| | or ``NULL`` if caused by an exception. |
+-------------------------------+----------------------------------------+
| :c:data:`PyTrace_C_CALL` | Function object being called. |
+-------------------------------+----------------------------------------+
| :c:data:`PyTrace_C_EXCEPTION` | Function object being called. |
+-------------------------------+----------------------------------------+
| :c:data:`PyTrace_C_RETURN` | Function object being called. |
+-------------------------------+----------------------------------------+
| :c:data:`PyTrace_OPCODE` | Always :c:data:`Py_None`. |
+-------------------------------+----------------------------------------+
.. c:var:: int PyTrace_CALL
The value of the *what* parameter to a :c:type:`Py_tracefunc` function when a new
call to a function or method is being reported, or a new entry into a generator.
Note that the creation of the iterator for a generator function is not reported
as there is no control transfer to the Python bytecode in the corresponding
frame.
.. c:var:: int PyTrace_EXCEPTION
The value of the *what* parameter to a :c:type:`Py_tracefunc` function when an
exception has been raised. The callback function is called with this value for
*what* when after any bytecode is processed after which the exception becomes
set within the frame being executed. The effect of this is that as exception
propagation causes the Python stack to unwind, the callback is called upon
return to each frame as the exception propagates. Only trace functions receive
these events; they are not needed by the profiler.
.. c:var:: int PyTrace_LINE
The value passed as the *what* parameter to a :c:type:`Py_tracefunc` function
(but not a profiling function) when a line-number event is being reported.
It may be disabled for a frame by setting :attr:`~frame.f_trace_lines` to
*0* on that frame.
.. c:var:: int PyTrace_RETURN
The value for the *what* parameter to :c:type:`Py_tracefunc` functions when a
call is about to return.
.. c:var:: int PyTrace_C_CALL
The value for the *what* parameter to :c:type:`Py_tracefunc` functions when a C
function is about to be called.
.. c:var:: int PyTrace_C_EXCEPTION
The value for the *what* parameter to :c:type:`Py_tracefunc` functions when a C
function has raised an exception.
.. c:var:: int PyTrace_C_RETURN
The value for the *what* parameter to :c:type:`Py_tracefunc` functions when a C
function has returned.
.. c:var:: int PyTrace_OPCODE
The value for the *what* parameter to :c:type:`Py_tracefunc` functions (but not
profiling functions) when a new opcode is about to be executed. This event is
not emitted by default: it must be explicitly requested by setting
:attr:`~frame.f_trace_opcodes` to *1* on the frame.
.. c:function:: void PyEval_SetProfile(Py_tracefunc func, PyObject *obj)
Set the profiler function to *func*. The *obj* parameter is passed to the
function as its first parameter, and may be any Python object, or ``NULL``. If
the profile function needs to maintain state, using a different value for *obj*
for each thread provides a convenient and thread-safe place to store it. The
profile function is called for all monitored events except :c:data:`PyTrace_LINE`
:c:data:`PyTrace_OPCODE` and :c:data:`PyTrace_EXCEPTION`.
See also the :func:`sys.setprofile` function.
The caller must have an :term:`attached thread state`.
.. c:function:: void PyEval_SetProfileAllThreads(Py_tracefunc func, PyObject *obj)
Like :c:func:`PyEval_SetProfile` but sets the profile function in all running threads
belonging to the current interpreter instead of the setting it only on the current thread.
The caller must have an :term:`attached thread state`.
As :c:func:`PyEval_SetProfile`, this function ignores any exceptions raised while
setting the profile functions in all threads.
.. versionadded:: 3.12
.. c:function:: void PyEval_SetTrace(Py_tracefunc func, PyObject *obj)
Set the tracing function to *func*. This is similar to
:c:func:`PyEval_SetProfile`, except the tracing function does receive line-number
events and per-opcode events, but does not receive any event related to C function
objects being called. Any trace function registered using :c:func:`PyEval_SetTrace`
will not receive :c:data:`PyTrace_C_CALL`, :c:data:`PyTrace_C_EXCEPTION` or
:c:data:`PyTrace_C_RETURN` as a value for the *what* parameter.
See also the :func:`sys.settrace` function.
The caller must have an :term:`attached thread state`.
.. c:function:: void PyEval_SetTraceAllThreads(Py_tracefunc func, PyObject *obj)
Like :c:func:`PyEval_SetTrace` but sets the tracing function in all running threads
belonging to the current interpreter instead of the setting it only on the current thread.
The caller must have an :term:`attached thread state`.
As :c:func:`PyEval_SetTrace`, this function ignores any exceptions raised while
setting the trace functions in all threads.
.. versionadded:: 3.12
Reference tracing
=================
.. versionadded:: 3.13
.. c:type:: int (*PyRefTracer)(PyObject *, int event, void* data)
The type of the trace function registered using :c:func:`PyRefTracer_SetTracer`.
The first parameter is a Python object that has been just created (when **event**
is set to :c:data:`PyRefTracer_CREATE`) or about to be destroyed (when **event**
is set to :c:data:`PyRefTracer_DESTROY`). The **data** argument is the opaque pointer
that was provided when :c:func:`PyRefTracer_SetTracer` was called.
If a new tracing function is registered replacing the current one, a call to the
trace function will be made with the object set to **NULL** and **event** set to
:c:data:`PyRefTracer_TRACKER_REMOVED`. This will happen just before the new
function is registered.
.. versionadded:: 3.13
.. c:var:: int PyRefTracer_CREATE
The value for the *event* parameter to :c:type:`PyRefTracer` functions when a Python
object has been created.
.. c:var:: int PyRefTracer_DESTROY
The value for the *event* parameter to :c:type:`PyRefTracer` functions when a Python
object has been destroyed.
.. c:var:: int PyRefTracer_TRACKER_REMOVED
The value for the *event* parameter to :c:type:`PyRefTracer` functions when the
current tracer is about to be replaced by a new one.
.. versionadded:: 3.14
.. c:function:: int PyRefTracer_SetTracer(PyRefTracer tracer, void *data)
Register a reference tracer function. The function will be called when a new
Python object has been created or when an object is going to be destroyed. If
**data** is provided it must be an opaque pointer that will be provided when
the tracer function is called. Return ``0`` on success. Set an exception and
return ``-1`` on error.
Note that tracer functions **must not** create Python objects inside or
otherwise the call will be re-entrant. The tracer also **must not** clear
any existing exception or set an exception. A :term:`thread state` will be active
every time the tracer function is called.
There must be an :term:`attached thread state` when calling this function.
If another tracer function was already registered, the old function will be
called with **event** set to :c:data:`PyRefTracer_TRACKER_REMOVED` just before
the new function is registered.
.. versionadded:: 3.13
.. c:function:: PyRefTracer PyRefTracer_GetTracer(void** data)
Get the registered reference tracer function and the value of the opaque data
pointer that was registered when :c:func:`PyRefTracer_SetTracer` was called.
If no tracer was registered this function will return NULL and will set the
**data** pointer to NULL.
There must be an :term:`attached thread state` when calling this function.
.. versionadded:: 3.13

5
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@ -109,9 +109,8 @@ Sequence Protocol
Alias for :c:func:`PySequence_Contains`.
.. deprecated:: 3.14
The function is :term:`soft deprecated` and should no longer be used to
write new code.
.. soft-deprecated:: 3.14
The function should no longer be used to write new code.
.. c:function:: Py_ssize_t PySequence_Index(PyObject *o, PyObject *value)

38
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@ -5,9 +5,6 @@
Set Objects
-----------
.. sectionauthor:: Raymond D. Hettinger <python@rcn.com>
.. index::
pair: object; set
pair: object; frozenset
@ -92,6 +89,11 @@ the constructor functions work with any iterable Python object.
actually iterable. The constructor is also useful for copying a set
(``c=set(s)``).
.. note::
The operation is atomic on :term:`free threading <free-threaded build>`
when *iterable* is a :class:`set`, :class:`frozenset`, :class:`dict` or :class:`frozendict`.
.. c:function:: PyObject* PyFrozenSet_New(PyObject *iterable)
@ -100,6 +102,11 @@ the constructor functions work with any iterable Python object.
set on success or ``NULL`` on failure. Raise :exc:`TypeError` if *iterable* is
not actually iterable.
.. note::
The operation is atomic on :term:`free threading <free-threaded build>`
when *iterable* is a :class:`set`, :class:`frozenset`, :class:`dict` or :class:`frozendict`.
The following functions and macros are available for instances of :class:`set`
or :class:`frozenset` or instances of their subtypes.
@ -127,6 +134,10 @@ or :class:`frozenset` or instances of their subtypes.
the *key* is unhashable. Raise :exc:`SystemError` if *anyset* is not a
:class:`set`, :class:`frozenset`, or an instance of a subtype.
.. note::
The operation is atomic on :term:`free threading <free-threaded build>`
when *key* is :class:`str`, :class:`int`, :class:`float`, :class:`bool` or :class:`bytes`.
.. c:function:: int PySet_Add(PyObject *set, PyObject *key)
@ -138,6 +149,12 @@ or :class:`frozenset` or instances of their subtypes.
:exc:`SystemError` if *set* is not an instance of :class:`set` or its
subtype.
.. note::
The operation is atomic on :term:`free threading <free-threaded build>`
when *key* is :class:`str`, :class:`int`, :class:`float`, :class:`bool` or :class:`bytes`.
The following functions are available for instances of :class:`set` or its
subtypes but not for instances of :class:`frozenset` or its subtypes.
@ -152,6 +169,11 @@ subtypes but not for instances of :class:`frozenset` or its subtypes.
temporary frozensets. Raise :exc:`SystemError` if *set* is not an
instance of :class:`set` or its subtype.
.. note::
The operation is atomic on :term:`free threading <free-threaded build>`
when *key* is :class:`str`, :class:`int`, :class:`float`, :class:`bool` or :class:`bytes`.
.. c:function:: PyObject* PySet_Pop(PyObject *set)
@ -167,13 +189,19 @@ subtypes but not for instances of :class:`frozenset` or its subtypes.
success. Return ``-1`` and raise :exc:`SystemError` if *set* is not an instance of
:class:`set` or its subtype.
.. note::
In the :term:`free-threaded build`, the set is emptied before its entries
are cleared, so other threads will observe an empty set rather than
intermediate states.
Deprecated API
^^^^^^^^^^^^^^
.. c:macro:: PySet_MINSIZE
A :term:`soft deprecated` constant representing the size of an internal
A constant representing the size of an internal
preallocated table inside :c:type:`PySetObject` instances.
This is documented solely for completeness, as there are no guarantees
@ -183,3 +211,5 @@ Deprecated API
:c:macro:`!PySet_MINSIZE` can be replaced with a small constant like ``8``.
If looking for the size of a set, use :c:func:`PySet_Size` instead.
.. soft-deprecated:: 3.14

284
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@ -51,135 +51,212 @@ It is generally intended for specialized, low-level tools like debuggers.
Projects that use this API are expected to follow
CPython development and spend extra effort adjusting to changes.
.. _stable-abi:
.. _stable-application-binary-interface:
Stable Application Binary Interface
===================================
Stable Application Binary Interfaces
====================================
For simplicity, this document talks about *extensions*, but the Limited API
and Stable ABI work the same way for all uses of the API – for example,
embedding Python.
.. _limited-c-api:
Limited C API
-------------
Python 3.2 introduced the *Limited API*, a subset of Python's C API.
Extensions that only use the Limited API can be
compiled once and be loaded on multiple versions of Python.
Contents of the Limited API are :ref:`listed below <limited-api-list>`.
.. c:macro:: Py_LIMITED_API
Define this macro before including ``Python.h`` to opt in to only use
the Limited API, and to select the Limited API version.
Define ``Py_LIMITED_API`` to the value of :c:macro:`PY_VERSION_HEX`
corresponding to the lowest Python version your extension supports.
The extension will be ABI-compatible with all Python 3 releases
from the specified one onward, and can use Limited API introduced up to that
version.
Rather than using the ``PY_VERSION_HEX`` macro directly, hardcode a minimum
minor version (e.g. ``0x030A0000`` for Python 3.10) for stability when
compiling with future Python versions.
You can also define ``Py_LIMITED_API`` to ``3``. This works the same as
``0x03020000`` (Python 3.2, the version that introduced Limited API).
.. _stable-abi:
Stable ABI
----------
To enable this, Python provides a *Stable ABI*: a set of symbols that will
remain ABI-compatible across Python 3.x versions.
Python's :dfn:`Stable ABI` allows extensions to be compatible with multiple
versions of Python, without recompilation.
.. note::
The Stable ABI prevents ABI issues, like linker errors due to missing
symbols or data corruption due to changes in structure layouts or function
signatures.
However, other changes in Python can change the *behavior* of extensions.
See Python's Backwards Compatibility Policy (:pep:`387`) for details.
For simplicity, this document talks about *extensions*, but Stable ABI
works the same way for all uses of the API – for example, embedding Python.
The Stable ABI contains symbols exposed in the :ref:`Limited API
<limited-c-api>`, but also other ones – for example, functions necessary to
support older versions of the Limited API.
There are two Stable ABIs:
On Windows, extensions that use the Stable ABI should be linked against
- ``abi3``, introduced in Python 3.2, is compatible with
**non**-:term:`free-threaded <free-threaded build>` builds of CPython.
- ``abi3t``, introduced in Python 3.15, is compatible with
:term:`free-threaded <free-threaded build>` builds of CPython.
It has stricter API limitations than ``abi3``.
.. versionadded:: next
``abi3t`` was added in :pep:`803`
It is possible for an extension to be compiled for *both* ``abi3`` and
``abi3t`` at the same time; the result will be compatible with
both free-threaded and non-free-threaded builds of Python.
Currently, this has no downsides compared to compiling for ``abi3t`` only.
Each Stable ABI is versioned using the first two numbers of the Python version.
For example, Stable ABI 3.14 corresponds to Python 3.14.
An extension compiled for Stable ABI 3.x is ABI-compatible with Python 3.x
and above.
Extensions that target a stable ABI must only use a limited subset of
the C API. This subset is known as the :dfn:`Limited API`; its contents
are :ref:`listed below <limited-api-list>`.
On Windows, extensions that use a Stable ABI should be linked against
``python3.dll`` rather than a version-specific library such as
``python39.dll``.
This library only exposes the relevant symbols.
On some platforms, Python will look for and load shared library files named
with the ``abi3`` tag (e.g. ``mymodule.abi3.so``).
It does not check if such extensions conform to a Stable ABI.
The user (or their packaging tools) need to ensure that, for example,
extensions built with the 3.10+ Limited API are not installed for lower
with the ``abi3`` or ``abi3t`` tag (for example, ``mymodule.abi3.so``).
:term:`Free-threaded <free-threaded build>` interpreters only recognize the
``abi3t`` tag, while non-free-threaded ones will prefer ``abi3`` but fall back
to ``abi3t``.
Thus, extensions compatible with both ABIs should use the ``abi3t`` tag.
Python does not necessarily check that extensions it loads
have compatible ABI.
Extension authors are encouraged to add a check using the :c:macro:`Py_mod_abi`
slot or the :c:func:`PyABIInfo_Check` function, but the user
(or their packaging tool) is ultimately responsible for ensuring that,
for example, extensions built for Stable ABI 3.10 are not installed for lower
versions of Python.
All functions in the Stable ABI are present as functions in Python's shared
library, not solely as macros. This makes them usable from languages that don't
use the C preprocessor.
All functions in Stable ABI are present as functions in Python's shared
library, not solely as macros.
This makes them usable are usable from languages that don't use the C
preprocessor, including Python's :py:mod:`ctypes`.
Limited API Scope and Performance
---------------------------------
.. _abi3-compiling:
The goal for the Limited API is to allow everything that is possible with the
Compiling for Stable ABI
------------------------
.. note::
Build tools (such as, for example, meson-python, scikit-build-core,
or Setuptools) often have a mechanism for setting macros and synchronizing
them with extension filenames and other metadata.
Prefer using such a mechanism, if it exists, over defining the
macros manually.
The rest of this section is mainly relevant for tool authors, and for
people who compile extensions manually.
.. seealso:: `list of recommended tools`_ in the Python Packaging User Guide
.. _list of recommended tools: https://packaging.python.org/en/latest/guides/tool-recommendations/#build-backends-for-extension-modules
To compile for a Stable ABI, define one or both of the following macros
to the lowest Python version your extension should support, in
:c:macro:`Py_PACK_VERSION` format.
Typically, you should choose a specific value rather than the version of
the Python headers you are compiling against.
The macros must be defined before including ``Python.h``.
Since :c:macro:`Py_PACK_VERSION` is not available at this point, you
will need to use the numeric value directly.
For reference, the values for a few recent Python versions are:
.. version-hex-cheatsheet::
When one of the macros is defined, ``Python.h`` will only expose API that is
compatible with the given Stable ABI -- that is, the
:ref:`Limited API <limited-api-list>` plus some definitions that need to be
visible to the compiler but should not be used directly.
When both are defined, ``Python.h`` will only expose API compatible with
both Stable ABIs.
.. c:macro:: Py_LIMITED_API
Target ``abi3``, that is,
non-:term:`free-threaded builds <free-threaded build>` of CPython.
See :ref:`above <abi3-compiling>` for common information.
.. c:macro:: Py_TARGET_ABI3T
Target ``abi3t``, that is,
:term:`free-threaded builds <free-threaded build>` of CPython.
See :ref:`above <abi3-compiling>` for common information.
.. versionadded:: next
Both macros specify a target ABI; the different naming style is due to
backwards compatibility.
.. admonition:: Historical note
You can also define ``Py_LIMITED_API`` as ``3``. This works the same as
``0x03020000`` (Python 3.2, the version that introduced Stable ABI).
When both are defined, ``Python.h`` may, or may not, redefine
:c:macro:`!Py_LIMITED_API` to match :c:macro:`!Py_TARGET_ABI3T`.
On a :term:`free-threaded build` -- that is, when
:c:macro:`Py_GIL_DISABLED` is defined -- :c:macro:`!Py_TARGET_ABI3T`
defaults to the value of :c:macro:`!Py_LIMITED_API`.
This means that there are two ways to build for both ``abi3`` and ``abi3t``:
- define both :c:macro:`!Py_LIMITED_API` and :c:macro:`!Py_TARGET_ABI3T`, or
- define only :c:macro:`!Py_LIMITED_API` and:
- on Windows, define :c:macro:`!Py_GIL_DISABLED`;
- on other systems, use the headers of free-threaded build of Python.
.. _limited-api-scope-and-performance:
Stable ABI Scope and Performance
--------------------------------
The goal for Stable ABI is to allow everything that is possible with the
full C API, but possibly with a performance penalty.
Generally, compatibility with Stable ABI will require some changes to an
extension's source code.
For example, while :c:func:`PyList_GetItem` is available, its “unsafe” macro
For example, while :c:func:`PyList_GetItem` is available, its "unsafe" macro
variant :c:func:`PyList_GET_ITEM` is not.
The macro can be faster because it can rely on version-specific implementation
details of the list object.
Without ``Py_LIMITED_API`` defined, some C API functions are inlined or
replaced by macros.
Defining ``Py_LIMITED_API`` disables this inlining, allowing stability as
For another example, when *not* compiling for Stable ABI, some C API
functions are inlined or replaced by macros.
Compiling for Stable ABI disables this inlining, allowing stability as
Python's data structures are improved, but possibly reducing performance.
By leaving out the ``Py_LIMITED_API`` definition, it is possible to compile
a Limited API extension with a version-specific ABI. This can improve
performance for that Python version, but will limit compatibility.
Compiling with ``Py_LIMITED_API`` will then yield an extension that can be
distributed where a version-specific one is not available – for example,
for prereleases of an upcoming Python version.
By leaving out the :c:macro:`!Py_LIMITED_API` or :c:macro:`!Py_TARGET_ABI3T`
definition, it is possible to compile Stable-ABI-compatible source
for a version-specific ABI.
A potentially faster version-specific extension can then be distributed
alongside a version compiled for Stable ABI -- a slower but more compatible
fallback.
Limited API Caveats
-------------------
.. _limited-api-caveats:
Note that compiling with ``Py_LIMITED_API`` is *not* a complete guarantee that
code conforms to the :ref:`Limited API <limited-c-api>` or the :ref:`Stable ABI
<stable-abi>`. ``Py_LIMITED_API`` only covers definitions, but an API also
includes other issues, such as expected semantics.
Stable ABI Caveats
------------------
One issue that ``Py_LIMITED_API`` does not guard against is calling a function
with arguments that are invalid in a lower Python version.
Note that compiling for Stable ABI is *not* a complete guarantee that code will
be compatible with the expected Python versions.
Stable ABI prevents *ABI* issues, like linker errors due to missing
symbols or data corruption due to changes in structure layouts or function
signatures.
However, other changes in Python can change the *behavior* of extensions.
One issue that the :c:macro:`Py_TARGET_ABI3T` and :c:macro:`Py_LIMITED_API`
macros do not guard against is calling a function with arguments that are
invalid in a lower Python version.
For example, consider a function that starts accepting ``NULL`` for an
argument. In Python 3.9, ``NULL`` now selects a default behavior, but in
Python 3.8, the argument will be used directly, causing a ``NULL`` dereference
and crash. A similar argument works for fields of structs.
Another issue is that some struct fields are currently not hidden when
``Py_LIMITED_API`` is defined, even though they're part of the Limited API.
For these reasons, we recommend testing an extension with *all* minor Python
versions it supports, and preferably to build with the *lowest* such version.
versions it supports.
We also recommend reviewing documentation of all used API to check
if it is explicitly part of the Limited API. Even with ``Py_LIMITED_API``
defined, a few private declarations are exposed for technical reasons (or
even unintentionally, as bugs).
Also note that the Limited API is not necessarily stable: compiling with
``Py_LIMITED_API`` with Python 3.8 means that the extension will
run with Python 3.12, but it will not necessarily *compile* with Python 3.12.
In particular, parts of the Limited API may be deprecated and removed,
provided that the Stable ABI stays stable.
Also note that while compiling with ``Py_LIMITED_API`` 3.8 means that the
extension should *load* on Python 3.12, and *compile* with Python 3.12,
the same source will not necessarily compile with ``Py_LIMITED_API``
set to 3.12.
In general, parts of the Limited API may be deprecated and removed,
provided that Stable ABI stays stable.
.. _stable-abi-platform:
@ -189,12 +266,12 @@ Platform Considerations
ABI stability depends not only on Python, but also on the compiler used,
lower-level libraries and compiler options. For the purposes of
the :ref:`Stable ABI <stable-abi>`, these details define a “platform”. They
the :ref:`Stable ABIs <stable-abi>`, these details define a “platform”. They
usually depend on the OS type and processor architecture
It is the responsibility of each particular distributor of Python
to ensure that all Python versions on a particular platform are built
in a way that does not break the Stable ABI.
in a way that does not break the Stable ABIs, or the version-specific ABIs.
This is the case with Windows and macOS releases from ``python.org`` and many
third-party distributors.
@ -302,7 +379,7 @@ The full API is described below for advanced use cases.
.. c:macro:: PyABIInfo_STABLE
Specifies that the stable ABI is used.
Specifies that Stable ABI is used.
.. c:macro:: PyABIInfo_INTERNAL
@ -313,15 +390,22 @@ The full API is described below for advanced use cases.
.. c:macro:: PyABIInfo_FREETHREADED
Specifies ABI compatible with free-threading builds of CPython.
Specifies ABI compatible with :term:`free-threaded builds
<free-threaded build>` of CPython.
(That is, ones compiled with :option:`--disable-gil`; with ``t``
in :py:data:`sys.abiflags`)
.. c:macro:: PyABIInfo_GIL
Specifies ABI compatible with non-free-threading builds of CPython
Specifies ABI compatible with non-free-threaded builds of CPython
(ones compiled *without* :option:`--disable-gil`).
.. c:macro:: PyABIInfo_FREETHREADING_AGNOSTIC
Specifies ABI compatible with both free-threaded and
non-free-threaded builds of CPython, that is, both
``abi3`` and ``abi3t``.
.. c:member:: uint32_t build_version
The version of the Python headers used to build the code, in the format
@ -335,10 +419,11 @@ The full API is described below for advanced use cases.
The ABI version.
For the Stable ABI, this field should be the value of
:c:macro:`Py_LIMITED_API`
(except if :c:macro:`Py_LIMITED_API` is ``3``; use
:c:expr:`Py_PACK_VERSION(3, 2)` in that case).
For Stable ABI, this field should be the value of
:c:macro:`Py_LIMITED_API` or :c:macro:`Py_TARGET_ABI3T`.
If both are defined, use the smaller value.
(If :c:macro:`Py_LIMITED_API` is ``3``; use
:c:expr:`Py_PACK_VERSION(3, 2)` instead of ``3``.)
Otherwise, it should be set to :c:macro:`PY_VERSION_HEX`.
@ -355,12 +440,13 @@ The full API is described below for advanced use cases.
.. versionadded:: 3.15
.. _limited-c-api:
.. _limited-api-list:
Contents of Limited API
=======================
Currently, the :ref:`Limited API <limited-c-api>` includes the following items:
This is the definitive list of :ref:`Limited API <limited-c-api>` for
Python |version|:
.. limited-api-list::

35
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@ -33,6 +33,13 @@ under :ref:`reference counting <countingrefs>`.
The members must not be accessed directly; instead use macros such as
:c:macro:`Py_REFCNT` and :c:macro:`Py_TYPE`.
In the :ref:`Stable ABI <stable-abi>` for Free-Threaded Builds (``abi3t``),
this struct is opaque; its size and layout may change between
Python versions.
In Stable ABI for non-free-threaded builds (``abi3``), the
:c:member:`!ob_refcnt` and :c:member:`!ob_type` fields are available,
but using them directly is discouraged.
.. c:member:: Py_ssize_t ob_refcnt
The object's reference count, as returned by :c:macro:`Py_REFCNT`.
@ -48,6 +55,19 @@ under :ref:`reference counting <countingrefs>`.
Do not use this field directly; use :c:macro:`Py_TYPE` and
:c:func:`Py_SET_TYPE` instead.
.. c:member:: PyMutex ob_mutex
A :ref:`per-object lock <per-object-locks>`, present only in the :term:`free-threaded <free threading>`
build (when :c:macro:`Py_GIL_DISABLED` is defined).
This field is **reserved for use by the critical section API**
(:c:macro:`Py_BEGIN_CRITICAL_SECTION` / :c:macro:`Py_END_CRITICAL_SECTION`).
Do **not** lock it directly with ``PyMutex_Lock``; doing so can cause
deadlocks. If you need your own lock, add a separate :c:type:`PyMutex`
field to your object struct.
.. versionadded:: 3.13
.. c:type:: PyVarObject
@ -59,6 +79,19 @@ under :ref:`reference counting <countingrefs>`.
instead use macros such as :c:macro:`Py_SIZE`, :c:macro:`Py_REFCNT` and
:c:macro:`Py_TYPE`.
In the :ref:`Stable ABI <stable-abi>` for Free-Threaded Builds (``abi3t``),
this struct is opaque; its size and layout may change between
Python versions.
In Stable ABI for non-free-threaded builds (``abi3``), the
:c:member:`!ob_base` and :c:member:`!ob_size` fields are available,
but using them directly is discouraged.
.. c:member:: PyObject ob_base
Common object header.
Typically, this field is not accessed directly; instead
:c:type:`!PyVarObject` can be cast to :c:type:`PyObject`.
.. c:member:: Py_ssize_t ob_size
A size field, whose contents should be considered an object's internal
@ -410,7 +443,7 @@ There are these calling conventions:
These two constants are not used to indicate the calling convention but the
binding when use with methods of classes. These may not be used for functions
binding when used with methods of classes. These may not be used for functions
defined for modules. At most one of these flags may be set for any given
method.

491
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@ -0,0 +1,491 @@
.. highlight:: c
.. _sub-interpreter-support:
Multiple interpreters in a Python process
=========================================
While in most uses, you will only embed a single Python interpreter, there
are cases where you need to create several independent interpreters in the
same process and perhaps even in the same thread. Sub-interpreters allow
you to do that.
The "main" interpreter is the first one created when the runtime initializes.
It is usually the only Python interpreter in a process. Unlike sub-interpreters,
the main interpreter has unique process-global responsibilities like signal
handling. It is also responsible for execution during runtime initialization and
is usually the active interpreter during runtime finalization. The
:c:func:`PyInterpreterState_Main` function returns a pointer to its state.
You can switch between sub-interpreters using the :c:func:`PyThreadState_Swap`
function. You can create and destroy them using the following functions:
.. c:type:: PyInterpreterConfig
Structure containing most parameters to configure a sub-interpreter.
Its values are used only in :c:func:`Py_NewInterpreterFromConfig` and
never modified by the runtime.
.. versionadded:: 3.12
Structure fields:
.. c:member:: int use_main_obmalloc
If this is ``0`` then the sub-interpreter will use its own
"object" allocator state.
Otherwise it will use (share) the main interpreter's.
If this is ``0`` then
:c:member:`~PyInterpreterConfig.check_multi_interp_extensions`
must be ``1`` (non-zero).
If this is ``1`` then :c:member:`~PyInterpreterConfig.gil`
must not be :c:macro:`PyInterpreterConfig_OWN_GIL`.
.. c:member:: int allow_fork
If this is ``0`` then the runtime will not support forking the
process in any thread where the sub-interpreter is currently active.
Otherwise fork is unrestricted.
Note that the :mod:`subprocess` module still works
when fork is disallowed.
.. c:member:: int allow_exec
If this is ``0`` then the runtime will not support replacing the
current process via exec (e.g. :func:`os.execv`) in any thread
where the sub-interpreter is currently active.
Otherwise exec is unrestricted.
Note that the :mod:`subprocess` module still works
when exec is disallowed.
.. c:member:: int allow_threads
If this is ``0`` then the sub-interpreter's :mod:`threading` module
won't create threads.
Otherwise threads are allowed.
.. c:member:: int allow_daemon_threads
If this is ``0`` then the sub-interpreter's :mod:`threading` module
won't create daemon threads.
Otherwise daemon threads are allowed (as long as
:c:member:`~PyInterpreterConfig.allow_threads` is non-zero).
.. c:member:: int check_multi_interp_extensions
If this is ``0`` then all extension modules may be imported,
including legacy (single-phase init) modules,
in any thread where the sub-interpreter is currently active.
Otherwise only multi-phase init extension modules
(see :pep:`489`) may be imported.
(Also see :c:macro:`Py_mod_multiple_interpreters`.)
This must be ``1`` (non-zero) if
:c:member:`~PyInterpreterConfig.use_main_obmalloc` is ``0``.
.. c:member:: int gil
This determines the operation of the GIL for the sub-interpreter.
It may be one of the following:
.. c:namespace:: NULL
.. c:macro:: PyInterpreterConfig_DEFAULT_GIL
Use the default selection (:c:macro:`PyInterpreterConfig_SHARED_GIL`).
.. c:macro:: PyInterpreterConfig_SHARED_GIL
Use (share) the main interpreter's GIL.
.. c:macro:: PyInterpreterConfig_OWN_GIL
Use the sub-interpreter's own GIL.
If this is :c:macro:`PyInterpreterConfig_OWN_GIL` then
:c:member:`PyInterpreterConfig.use_main_obmalloc` must be ``0``.
.. c:function:: PyStatus Py_NewInterpreterFromConfig(PyThreadState **tstate_p, const PyInterpreterConfig *config)
.. index::
pair: module; builtins
pair: module; __main__
pair: module; sys
single: stdout (in module sys)
single: stderr (in module sys)
single: stdin (in module sys)
Create a new sub-interpreter. This is an (almost) totally separate environment
for the execution of Python code. In particular, the new interpreter has
separate, independent versions of all imported modules, including the
fundamental modules :mod:`builtins`, :mod:`__main__` and :mod:`sys`. The
table of loaded modules (``sys.modules``) and the module search path
(``sys.path``) are also separate. The new environment has no ``sys.argv``
variable. It has new standard I/O stream file objects ``sys.stdin``,
``sys.stdout`` and ``sys.stderr`` (however these refer to the same underlying
file descriptors).
The given *config* controls the options with which the interpreter
is initialized.
Upon success, *tstate_p* will be set to the first :term:`thread state`
created in the new sub-interpreter. This thread state is
:term:`attached <attached thread state>`.
Note that no actual thread is created; see the discussion of thread states
below. If creation of the new interpreter is unsuccessful,
*tstate_p* is set to ``NULL``;
no exception is set since the exception state is stored in the
:term:`attached thread state`, which might not exist.
Like all other Python/C API functions, an :term:`attached thread state`
must be present before calling this function, but it might be detached upon
returning. On success, the returned thread state will be :term:`attached <attached thread state>`.
If the sub-interpreter is created with its own :term:`GIL` then the
:term:`attached thread state` of the calling interpreter will be detached.
When the function returns, the new interpreter's :term:`thread state`
will be :term:`attached <attached thread state>` to the current thread and
the previous interpreter's :term:`attached thread state` will remain detached.
.. versionadded:: 3.12
Sub-interpreters are most effective when isolated from each other,
with certain functionality restricted::
PyInterpreterConfig config = {
.use_main_obmalloc = 0,
.allow_fork = 0,
.allow_exec = 0,
.allow_threads = 1,
.allow_daemon_threads = 0,
.check_multi_interp_extensions = 1,
.gil = PyInterpreterConfig_OWN_GIL,
};
PyThreadState *tstate = NULL;
PyStatus status = Py_NewInterpreterFromConfig(&tstate, &config);
if (PyStatus_Exception(status)) {
Py_ExitStatusException(status);
}
Note that the config is used only briefly and does not get modified.
During initialization the config's values are converted into various
:c:type:`PyInterpreterState` values. A read-only copy of the config
may be stored internally on the :c:type:`PyInterpreterState`.
.. index::
single: Py_FinalizeEx (C function)
single: Py_Initialize (C function)
Extension modules are shared between (sub-)interpreters as follows:
* For modules using multi-phase initialization,
e.g. :c:func:`PyModule_FromDefAndSpec`, a separate module object is
created and initialized for each interpreter.
Only C-level static and global variables are shared between these
module objects.
* For modules using legacy
:ref:`single-phase initialization <single-phase-initialization>`,
e.g. :c:func:`PyModule_Create`, the first time a particular extension
is imported, it is initialized normally, and a (shallow) copy of its
module's dictionary is squirreled away.
When the same extension is imported by another (sub-)interpreter, a new
module is initialized and filled with the contents of this copy; the
extension's ``init`` function is not called.
Objects in the module's dictionary thus end up shared across
(sub-)interpreters, which might cause unwanted behavior (see
`Bugs and caveats`_ below).
Note that this is different from what happens when an extension is
imported after the interpreter has been completely re-initialized by
calling :c:func:`Py_FinalizeEx` and :c:func:`Py_Initialize`; in that
case, the extension's ``initmodule`` function *is* called again.
As with multi-phase initialization, this means that only C-level static
and global variables are shared between these modules.
.. index:: single: close (in module os)
.. c:function:: PyThreadState* Py_NewInterpreter(void)
.. index::
pair: module; builtins
pair: module; __main__
pair: module; sys
single: stdout (in module sys)
single: stderr (in module sys)
single: stdin (in module sys)
Create a new sub-interpreter. This is essentially just a wrapper
around :c:func:`Py_NewInterpreterFromConfig` with a config that
preserves the existing behavior. The result is an unisolated
sub-interpreter that shares the main interpreter's GIL, allows
fork/exec, allows daemon threads, and allows single-phase init
modules.
.. c:function:: void Py_EndInterpreter(PyThreadState *tstate)
.. index:: single: Py_FinalizeEx (C function)
Destroy the (sub-)interpreter represented by the given :term:`thread state`.
The given thread state must be :term:`attached <attached thread state>`.
When the call returns, there will be no :term:`attached thread state`.
All thread states associated with this interpreter are destroyed.
:c:func:`Py_FinalizeEx` will destroy all sub-interpreters that
haven't been explicitly destroyed at that point.
.. _per-interpreter-gil:
A per-interpreter GIL
---------------------
.. versionadded:: 3.12
Using :c:func:`Py_NewInterpreterFromConfig` you can create
a sub-interpreter that is completely isolated from other interpreters,
including having its own GIL. The most important benefit of this
isolation is that such an interpreter can execute Python code without
being blocked by other interpreters or blocking any others. Thus a
single Python process can truly take advantage of multiple CPU cores
when running Python code. The isolation also encourages a different
approach to concurrency than that of just using threads.
(See :pep:`554` and :pep:`684`.)
Using an isolated interpreter requires vigilance in preserving that
isolation. That especially means not sharing any objects or mutable
state without guarantees about thread-safety. Even objects that are
otherwise immutable (e.g. ``None``, ``(1, 5)``) can't normally be shared
because of the refcount. One simple but less-efficient approach around
this is to use a global lock around all use of some state (or object).
Alternately, effectively immutable objects (like integers or strings)
can be made safe in spite of their refcounts by making them :term:`immortal`.
In fact, this has been done for the builtin singletons, small integers,
and a number of other builtin objects.
If you preserve isolation then you will have access to proper multi-core
computing without the complications that come with free-threading.
Failure to preserve isolation will expose you to the full consequences
of free-threading, including races and hard-to-debug crashes.
Aside from that, one of the main challenges of using multiple isolated
interpreters is how to communicate between them safely (not break
isolation) and efficiently. The runtime and stdlib do not provide
any standard approach to this yet. A future stdlib module would help
mitigate the effort of preserving isolation and expose effective tools
for communicating (and sharing) data between interpreters.
Bugs and caveats
----------------
Because sub-interpreters (and the main interpreter) are part of the same
process, the insulation between them isn't perfect --- for example, using
low-level file operations like :func:`os.close` they can
(accidentally or maliciously) affect each other's open files. Because of the
way extensions are shared between (sub-)interpreters, some extensions may not
work properly; this is especially likely when using single-phase initialization
or (static) global variables.
It is possible to insert objects created in one sub-interpreter into
a namespace of another (sub-)interpreter; this should be avoided if possible.
Special care should be taken to avoid sharing user-defined functions,
methods, instances or classes between sub-interpreters, since import
operations executed by such objects may affect the wrong (sub-)interpreter's
dictionary of loaded modules. It is equally important to avoid sharing
objects from which the above are reachable.
Also note that combining this functionality with ``PyGILState_*`` APIs
is delicate, because these APIs assume a bijection between Python thread states
and OS-level threads, an assumption broken by the presence of sub-interpreters.
It is highly recommended that you don't switch sub-interpreters between a pair
of matching :c:func:`PyGILState_Ensure` and :c:func:`PyGILState_Release` calls.
Furthermore, extensions (such as :mod:`ctypes`) using these APIs to allow calling
of Python code from non-Python created threads will probably be broken when using
sub-interpreters.
High-level APIs
---------------
.. c:type:: PyInterpreterState
This data structure represents the state shared by a number of cooperating
threads. Threads belonging to the same interpreter share their module
administration and a few other internal items. There are no public members in
this structure.
Threads belonging to different interpreters initially share nothing, except
process state like available memory, open file descriptors and such. The global
interpreter lock is also shared by all threads, regardless of to which
interpreter they belong.
.. versionchanged:: 3.12
:pep:`684` introduced the possibility
of a :ref:`per-interpreter GIL <per-interpreter-gil>`.
See :c:func:`Py_NewInterpreterFromConfig`.
.. c:function:: PyInterpreterState* PyInterpreterState_Get(void)
Get the current interpreter.
Issue a fatal error if there is no :term:`attached thread state`.
It cannot return NULL.
.. versionadded:: 3.9
.. c:function:: int64_t PyInterpreterState_GetID(PyInterpreterState *interp)
Return the interpreter's unique ID. If there was any error in doing
so then ``-1`` is returned and an error is set.
The caller must have an :term:`attached thread state`.
.. versionadded:: 3.7
.. c:function:: PyObject* PyInterpreterState_GetDict(PyInterpreterState *interp)
Return a dictionary in which interpreter-specific data may be stored.
If this function returns ``NULL`` then no exception has been raised and
the caller should assume no interpreter-specific dict is available.
This is not a replacement for :c:func:`PyModule_GetState()`, which
extensions should use to store interpreter-specific state information.
The returned dictionary is borrowed from the interpreter and is valid until
interpreter shutdown.
.. versionadded:: 3.8
.. c:type:: PyObject* (*_PyFrameEvalFunction)(PyThreadState *tstate, _PyInterpreterFrame *frame, int throwflag)
Type of a frame evaluation function.
The *throwflag* parameter is used by the ``throw()`` method of generators:
if non-zero, handle the current exception.
.. versionchanged:: 3.9
The function now takes a *tstate* parameter.
.. versionchanged:: 3.11
The *frame* parameter changed from ``PyFrameObject*`` to ``_PyInterpreterFrame*``.
.. c:function:: _PyFrameEvalFunction _PyInterpreterState_GetEvalFrameFunc(PyInterpreterState *interp)
Get the frame evaluation function.
See the :pep:`523` "Adding a frame evaluation API to CPython".
.. versionadded:: 3.9
.. c:function:: void _PyInterpreterState_SetEvalFrameFunc(PyInterpreterState *interp, _PyFrameEvalFunction eval_frame)
Set the frame evaluation function.
See the :pep:`523` "Adding a frame evaluation API to CPython".
.. versionadded:: 3.9
.. c:function:: void _PyInterpreterState_SetEvalFrameAllowSpecialization(PyInterpreterState *interp, int allow_specialization)
Enables or disables specialization why a custom frame evaluator is in place.
If *allow_specialization* is non-zero, the adaptive specializer will
continue to specialize bytecodes even though a custom eval frame function
is set. When *allow_specialization* is zero, setting a custom eval frame
disables specialization. The standard interpreter loop will continue to deopt
while a frame evaluation API is in place - the frame evaluation function needs
to handle the specialized opcodes to take advantage of this.
.. versionadded:: 3.15
.. c:function:: int _PyInterpreterState_IsSpecializationEnabled(PyInterpreterState *interp)
Return non-zero if adaptive specialization is enabled for the interpreter.
Specialization is enabled when no custom eval frame function is set, or
when one is set with *allow_specialization* enabled.
.. versionadded:: 3.15
Low-level APIs
--------------
All of the following functions must be called after :c:func:`Py_Initialize`.
.. versionchanged:: 3.7
:c:func:`Py_Initialize()` now initializes the :term:`GIL`
and sets an :term:`attached thread state`.
.. c:function:: PyInterpreterState* PyInterpreterState_New()
Create a new interpreter state object. An :term:`attached thread state` is not needed,
but may optionally exist if it is necessary to serialize calls to this
function.
.. audit-event:: cpython.PyInterpreterState_New "" c.PyInterpreterState_New
.. c:function:: void PyInterpreterState_Clear(PyInterpreterState *interp)
Reset all information in an interpreter state object. There must be
an :term:`attached thread state` for the interpreter.
.. audit-event:: cpython.PyInterpreterState_Clear "" c.PyInterpreterState_Clear
.. c:function:: void PyInterpreterState_Delete(PyInterpreterState *interp)
Destroy an interpreter state object. There **should not** be an
:term:`attached thread state` for the target interpreter. The interpreter
state must have been reset with a previous call to :c:func:`PyInterpreterState_Clear`.
.. _advanced-debugging:
Advanced debugger support
-------------------------
These functions are only intended to be used by advanced debugging tools.
.. c:function:: PyInterpreterState* PyInterpreterState_Head()
Return the interpreter state object at the head of the list of all such objects.
.. c:function:: PyInterpreterState* PyInterpreterState_Main()
Return the main interpreter state object.
.. c:function:: PyInterpreterState* PyInterpreterState_Next(PyInterpreterState *interp)
Return the next interpreter state object after *interp* from the list of all
such objects.
.. c:function:: PyThreadState * PyInterpreterState_ThreadHead(PyInterpreterState *interp)
Return the pointer to the first :c:type:`PyThreadState` object in the list of
threads associated with the interpreter *interp*.
.. c:function:: PyThreadState* PyThreadState_Next(PyThreadState *tstate)
Return the next thread state object after *tstate* from the list of all such
objects belonging to the same :c:type:`PyInterpreterState` object.

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.. highlight:: c
.. _synchronization:
Synchronization primitives
==========================
The C-API provides a basic mutual exclusion lock.
.. c:type:: PyMutex
A mutual exclusion lock. The :c:type:`!PyMutex` should be initialized to
zero to represent the unlocked state. For example::
PyMutex mutex = {0};
Instances of :c:type:`!PyMutex` should not be copied or moved. Both the
contents and address of a :c:type:`!PyMutex` are meaningful, and it must
remain at a fixed, writable location in memory.
.. note::
A :c:type:`!PyMutex` currently occupies one byte, but the size should be
considered unstable. The size may change in future Python releases
without a deprecation period.
.. versionadded:: 3.13
.. c:function:: void PyMutex_Lock(PyMutex *m)
Lock mutex *m*. If another thread has already locked it, the calling
thread will block until the mutex is unlocked. While blocked, the thread
will temporarily detach the :term:`thread state <attached thread state>` if one exists.
.. versionadded:: 3.13
.. c:function:: void PyMutex_Unlock(PyMutex *m)
Unlock mutex *m*. The mutex must be locked --- otherwise, the function will
issue a fatal error.
.. versionadded:: 3.13
.. c:function:: int PyMutex_IsLocked(PyMutex *m)
Returns non-zero if the mutex *m* is currently locked, zero otherwise.
.. note::
This function is intended for use in assertions and debugging only and
should not be used to make concurrency control decisions, as the lock
state may change immediately after the check.
.. versionadded:: 3.14
.. _python-critical-section-api:
Python critical section API
---------------------------
The critical section API provides a deadlock avoidance layer on top of
per-object locks for :term:`free-threaded <free threading>` CPython. They are
intended to replace reliance on the :term:`global interpreter lock`, and are
no-ops in versions of Python with the global interpreter lock.
Critical sections are intended to be used for custom types implemented
in C-API extensions. They should generally not be used with built-in types like
:class:`list` and :class:`dict` because their public C-APIs
already use critical sections internally, with the notable
exception of :c:func:`PyDict_Next`, which requires critical section
to be acquired externally.
Critical sections avoid deadlocks by implicitly suspending active critical
sections, hence, they do not provide exclusive access such as provided by
traditional locks like :c:type:`PyMutex`. When a critical section is started,
the per-object lock for the object is acquired. If the code executed inside the
critical section calls C-API functions then it can suspend the critical section thereby
releasing the per-object lock, so other threads can acquire the per-object lock
for the same object.
Variants that accept :c:type:`PyMutex` pointers rather than Python objects are also
available. Use these variants to start a critical section in a situation where
there is no :c:type:`PyObject` -- for example, when working with a C type that
does not extend or wrap :c:type:`PyObject` but still needs to call into the C
API in a manner that might lead to deadlocks.
The functions and structs used by the macros are exposed for cases
where C macros are not available. They should only be used as in the
given macro expansions. Note that the sizes and contents of the structures may
change in future Python versions.
.. note::
Operations that need to lock two objects at once must use
:c:macro:`Py_BEGIN_CRITICAL_SECTION2`. You *cannot* use nested critical
sections to lock more than one object at once, because the inner critical
section may suspend the outer critical sections. This API does not provide
a way to lock more than two objects at once.
Example usage::
static PyObject *
set_field(MyObject *self, PyObject *value)
{
Py_BEGIN_CRITICAL_SECTION(self);
Py_SETREF(self->field, Py_XNewRef(value));
Py_END_CRITICAL_SECTION();
Py_RETURN_NONE;
}
In the above example, :c:macro:`Py_SETREF` calls :c:macro:`Py_DECREF`, which
can call arbitrary code through an object's deallocation function. The critical
section API avoids potential deadlocks due to reentrancy and lock ordering
by allowing the runtime to temporarily suspend the critical section if the
code triggered by the finalizer blocks and calls :c:func:`PyEval_SaveThread`.
.. c:macro:: Py_BEGIN_CRITICAL_SECTION(op)
Acquires the per-object lock for the object *op* and begins a
critical section.
In the free-threaded build, this macro expands to::
{
PyCriticalSection _py_cs;
PyCriticalSection_Begin(&_py_cs, (PyObject*)(op))
In the default build, this macro expands to ``{``.
.. versionadded:: 3.13
.. c:macro:: Py_BEGIN_CRITICAL_SECTION_MUTEX(m)
Locks the mutex *m* and begins a critical section.
In the free-threaded build, this macro expands to::
{
PyCriticalSection _py_cs;
PyCriticalSection_BeginMutex(&_py_cs, m)
Note that unlike :c:macro:`Py_BEGIN_CRITICAL_SECTION`, there is no cast for
the argument of the macro - it must be a :c:type:`PyMutex` pointer.
On the default build, this macro expands to ``{``.
.. versionadded:: 3.14
.. c:macro:: Py_END_CRITICAL_SECTION()
Ends the critical section and releases the per-object lock.
In the free-threaded build, this macro expands to::
PyCriticalSection_End(&_py_cs);
}
In the default build, this macro expands to ``}``.
.. versionadded:: 3.13
.. c:macro:: Py_BEGIN_CRITICAL_SECTION2(a, b)
Acquires the per-object locks for the objects *a* and *b* and begins a
critical section. The locks are acquired in a consistent order (lowest
address first) to avoid lock ordering deadlocks.
In the free-threaded build, this macro expands to::
{
PyCriticalSection2 _py_cs2;
PyCriticalSection2_Begin(&_py_cs2, (PyObject*)(a), (PyObject*)(b))
In the default build, this macro expands to ``{``.
.. versionadded:: 3.13
.. c:macro:: Py_BEGIN_CRITICAL_SECTION2_MUTEX(m1, m2)
Locks the mutexes *m1* and *m2* and begins a critical section.
In the free-threaded build, this macro expands to::
{
PyCriticalSection2 _py_cs2;
PyCriticalSection2_BeginMutex(&_py_cs2, m1, m2)
Note that unlike :c:macro:`Py_BEGIN_CRITICAL_SECTION2`, there is no cast for
the arguments of the macro - they must be :c:type:`PyMutex` pointers.
On the default build, this macro expands to ``{``.
.. versionadded:: 3.14
.. c:macro:: Py_END_CRITICAL_SECTION2()
Ends the critical section and releases the per-object locks.
In the free-threaded build, this macro expands to::
PyCriticalSection2_End(&_py_cs2);
}
In the default build, this macro expands to ``}``.
.. versionadded:: 3.13
Legacy locking APIs
-------------------
These APIs are obsolete since Python 3.13 with the introduction of
:c:type:`PyMutex`.
.. versionchanged:: 3.15
These APIs are now a simple wrapper around ``PyMutex``.
.. c:type:: PyThread_type_lock
A pointer to a mutual exclusion lock.
.. c:type:: PyLockStatus
The result of acquiring a lock with a timeout.
.. c:namespace:: NULL
.. c:enumerator:: PY_LOCK_FAILURE
Failed to acquire the lock.
.. c:enumerator:: PY_LOCK_ACQUIRED
The lock was successfully acquired.
.. c:enumerator:: PY_LOCK_INTR
The lock was interrupted by a signal.
.. c:function:: PyThread_type_lock PyThread_allocate_lock(void)
Allocate a new lock.
On success, this function returns a lock; on failure, this
function returns ``0`` without an exception set.
The caller does not need to hold an :term:`attached thread state`.
.. versionchanged:: 3.15
This function now always uses :c:type:`PyMutex`. In prior versions, this
would use a lock provided by the operating system.
.. c:function:: void PyThread_free_lock(PyThread_type_lock lock)
Destroy *lock*. The lock should not be held by any thread when calling
this.
The caller does not need to hold an :term:`attached thread state`.
.. c:function:: PyLockStatus PyThread_acquire_lock_timed(PyThread_type_lock lock, long long microseconds, int intr_flag)
Acquire *lock* with a timeout.
This will wait for *microseconds* microseconds to acquire the lock. If the
timeout expires, this function returns :c:enumerator:`PY_LOCK_FAILURE`.
If *microseconds* is ``-1``, this will wait indefinitely until the lock has
been released.
If *intr_flag* is ``1``, acquiring the lock may be interrupted by a signal,
in which case this function returns :c:enumerator:`PY_LOCK_INTR`. Upon
interruption, it's generally expected that the caller makes a call to
:c:func:`Py_MakePendingCalls` to propagate an exception to Python code.
If the lock is successfully acquired, this function returns
:c:enumerator:`PY_LOCK_ACQUIRED`.
The caller does not need to hold an :term:`attached thread state`.
.. c:function:: int PyThread_acquire_lock(PyThread_type_lock lock, int waitflag)
Acquire *lock*.
If *waitflag* is ``1`` and another thread currently holds the lock, this
function will wait until the lock can be acquired and will always return
``1``.
If *waitflag* is ``0`` and another thread holds the lock, this function will
not wait and instead return ``0``. If the lock is not held by any other
thread, then this function will acquire it and return ``1``.
Unlike :c:func:`PyThread_acquire_lock_timed`, acquiring the lock cannot be
interrupted by a signal.
The caller does not need to hold an :term:`attached thread state`.
.. c:function:: int PyThread_release_lock(PyThread_type_lock lock)
Release *lock*. If *lock* is not held, then this function issues a
fatal error.
The caller does not need to hold an :term:`attached thread state`.

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.. highlight:: c
.. _threads:
Thread states and the global interpreter lock
=============================================
.. index::
single: global interpreter lock
single: interpreter lock
single: lock, interpreter
Unless on a :term:`free-threaded build` of :term:`CPython`,
the Python interpreter is generally not thread-safe. In order to support
multi-threaded Python programs, there's a global lock, called the :term:`global
interpreter lock` or :term:`GIL`, that must be held by a thread before
accessing Python objects. Without the lock, even the simplest operations
could cause problems in a multi-threaded program: for example, when
two threads simultaneously increment the reference count of the same object, the
reference count could end up being incremented only once instead of twice.
As such, only a thread that holds the GIL may operate on Python objects or
invoke Python's C API.
.. index:: single: setswitchinterval (in module sys)
In order to emulate concurrency, the interpreter regularly tries to switch
threads between bytecode instructions (see :func:`sys.setswitchinterval`).
This is why locks are also necessary for thread-safety in pure-Python code.
Additionally, the global interpreter lock is released around blocking I/O
operations, such as reading or writing to a file. From the C API, this is done
by :ref:`detaching the thread state <detaching-thread-state>`.
.. index::
single: PyThreadState (C type)
The Python interpreter keeps some thread-local information inside
a data structure called :c:type:`PyThreadState`, known as a :term:`thread state`.
Each thread has a thread-local pointer to a :c:type:`PyThreadState`; a thread state
referenced by this pointer is considered to be :term:`attached <attached thread state>`.
A thread can only have one :term:`attached thread state` at a time. An attached
thread state is typically analogous with holding the GIL, except on
free-threaded builds. On builds with the GIL enabled, attaching a thread state
will block until the GIL can be acquired. However, even on builds with the GIL
disabled, it is still required to have an attached thread state, as the interpreter
needs to keep track of which threads may access Python objects.
.. note::
Even on the free-threaded build, attaching a thread state may block, as the
GIL can be re-enabled or threads might be temporarily suspended (such as during
a garbage collection).
Generally, there will always be an attached thread state when using Python's
C API, including during embedding and when implementing methods, so it's uncommon
to need to set up a thread state on your own. Only in some specific cases, such
as in a :c:macro:`Py_BEGIN_ALLOW_THREADS` block or in a fresh thread, will the
thread not have an attached thread state.
If uncertain, check if :c:func:`PyThreadState_GetUnchecked` returns ``NULL``.
If it turns out that you do need to create a thread state, call :c:func:`PyThreadState_New`
followed by :c:func:`PyThreadState_Swap`, or use the dangerous
:c:func:`PyGILState_Ensure` function.
.. _detaching-thread-state:
Detaching the thread state from extension code
----------------------------------------------
Most extension code manipulating the :term:`thread state` has the following simple
structure::
Save the thread state in a local variable.
... Do some blocking I/O operation ...
Restore the thread state from the local variable.
This is so common that a pair of macros exists to simplify it::
Py_BEGIN_ALLOW_THREADS
... Do some blocking I/O operation ...
Py_END_ALLOW_THREADS
.. index::
single: Py_BEGIN_ALLOW_THREADS (C macro)
single: Py_END_ALLOW_THREADS (C macro)
The :c:macro:`Py_BEGIN_ALLOW_THREADS` macro opens a new block and declares a
hidden local variable; the :c:macro:`Py_END_ALLOW_THREADS` macro closes the
block.
The block above expands to the following code::
PyThreadState *_save;
_save = PyEval_SaveThread();
... Do some blocking I/O operation ...
PyEval_RestoreThread(_save);
.. index::
single: PyEval_RestoreThread (C function)
single: PyEval_SaveThread (C function)
Here is how these functions work:
The attached thread state implies that the GIL is held for the interpreter.
To detach it, :c:func:`PyEval_SaveThread` is called and the result is stored
in a local variable.
By detaching the thread state, the GIL is released, which allows other threads
to attach to the interpreter and execute while the current thread performs
blocking I/O. When the I/O operation is complete, the old thread state is
reattached by calling :c:func:`PyEval_RestoreThread`, which will wait until
the GIL can be acquired.
.. note::
Performing blocking I/O is the most common use case for detaching
the thread state, but it is also useful to call it over long-running
native code that doesn't need access to Python objects or Python's C API.
For example, the standard :mod:`zlib` and :mod:`hashlib` modules detach the
:term:`thread state <attached thread state>` when compressing or hashing
data.
On a :term:`free-threaded build`, the :term:`GIL` is usually out of the question,
but **detaching the thread state is still required**, because the interpreter
periodically needs to block all threads to get a consistent view of Python objects
without the risk of race conditions.
For example, CPython currently suspends all threads for a short period of time
while running the garbage collector.
.. warning::
Detaching the thread state can lead to unexpected behavior during interpreter
finalization. See :ref:`cautions-regarding-runtime-finalization` for more
details.
APIs
^^^^
The following macros are normally used without a trailing semicolon; look for
example usage in the Python source distribution.
.. note::
These macros are still necessary on the :term:`free-threaded build` to prevent
deadlocks.
.. c:macro:: Py_BEGIN_ALLOW_THREADS
This macro expands to ``{ PyThreadState *_save; _save = PyEval_SaveThread();``.
Note that it contains an opening brace; it must be matched with a following
:c:macro:`Py_END_ALLOW_THREADS` macro. See above for further discussion of this
macro.
.. c:macro:: Py_END_ALLOW_THREADS
This macro expands to ``PyEval_RestoreThread(_save); }``. Note that it contains
a closing brace; it must be matched with an earlier
:c:macro:`Py_BEGIN_ALLOW_THREADS` macro. See above for further discussion of
this macro.
.. c:macro:: Py_BLOCK_THREADS
This macro expands to ``PyEval_RestoreThread(_save);``: it is equivalent to
:c:macro:`Py_END_ALLOW_THREADS` without the closing brace.
.. c:macro:: Py_UNBLOCK_THREADS
This macro expands to ``_save = PyEval_SaveThread();``: it is equivalent to
:c:macro:`Py_BEGIN_ALLOW_THREADS` without the opening brace and variable
declaration.
Non-Python created threads
--------------------------
When threads are created using the dedicated Python APIs (such as the
:mod:`threading` module), a thread state is automatically associated with them,
However, when a thread is created from native code (for example, by a
third-party library with its own thread management), it doesn't hold an
attached thread state.
If you need to call Python code from these threads (often this will be part
of a callback API provided by the aforementioned third-party library),
you must first register these threads with the interpreter by
creating a new thread state and attaching it.
The most robust way to do this is through :c:func:`PyThreadState_New` followed
by :c:func:`PyThreadState_Swap`.
.. note::
``PyThreadState_New`` requires an argument pointing to the desired
interpreter; such a pointer can be acquired via a call to
:c:func:`PyInterpreterState_Get` from the code where the thread was
created.
For example::
/* The return value of PyInterpreterState_Get() from the
function that created this thread. */
PyInterpreterState *interp = thread_data->interp;
/* Create a new thread state for the interpreter. It does not start out
attached. */
PyThreadState *tstate = PyThreadState_New(interp);
/* Attach the thread state, which will acquire the GIL. */
PyThreadState_Swap(tstate);
/* Perform Python actions here. */
result = CallSomeFunction();
/* evaluate result or handle exception */
/* Destroy the thread state. No Python API allowed beyond this point. */
PyThreadState_Clear(tstate);
PyThreadState_DeleteCurrent();
.. warning::
If the interpreter finalized before ``PyThreadState_Swap`` was called, then
``interp`` will be a dangling pointer!
.. _gilstate:
Legacy API
----------
Another common pattern to call Python code from a non-Python thread is to use
:c:func:`PyGILState_Ensure` followed by a call to :c:func:`PyGILState_Release`.
These functions do not work well when multiple interpreters exist in the Python
process. If no Python interpreter has ever been used in the current thread (which
is common for threads created outside Python), ``PyGILState_Ensure`` will create
and attach a thread state for the "main" interpreter (the first interpreter in
the Python process).
Additionally, these functions have thread-safety issues during interpreter
finalization. Using ``PyGILState_Ensure`` during finalization will likely
crash the process.
Usage of these functions look like such::
PyGILState_STATE gstate;
gstate = PyGILState_Ensure();
/* Perform Python actions here. */
result = CallSomeFunction();
/* evaluate result or handle exception */
/* Release the thread. No Python API allowed beyond this point. */
PyGILState_Release(gstate);
.. _fork-and-threads:
Cautions about fork()
---------------------
Another important thing to note about threads is their behaviour in the face
of the C :c:func:`fork` call. On most systems with :c:func:`fork`, after a
process forks only the thread that issued the fork will exist. This has a
concrete impact both on how locks must be handled and on all stored state
in CPython's runtime.
The fact that only the "current" thread remains
means any locks held by other threads will never be released. Python solves
this for :func:`os.fork` by acquiring the locks it uses internally before
the fork, and releasing them afterwards. In addition, it resets any
:ref:`lock-objects` in the child. When extending or embedding Python, there
is no way to inform Python of additional (non-Python) locks that need to be
acquired before or reset after a fork. OS facilities such as
:c:func:`!pthread_atfork` would need to be used to accomplish the same thing.
Additionally, when extending or embedding Python, calling :c:func:`fork`
directly rather than through :func:`os.fork` (and returning to or calling
into Python) may result in a deadlock by one of Python's internal locks
being held by a thread that is defunct after the fork.
:c:func:`PyOS_AfterFork_Child` tries to reset the necessary locks, but is not
always able to.
The fact that all other threads go away also means that CPython's
runtime state there must be cleaned up properly, which :func:`os.fork`
does. This means finalizing all other :c:type:`PyThreadState` objects
belonging to the current interpreter and all other
:c:type:`PyInterpreterState` objects. Due to this and the special
nature of the :ref:`"main" interpreter <sub-interpreter-support>`,
:c:func:`fork` should only be called in that interpreter's "main"
thread, where the CPython global runtime was originally initialized.
The only exception is if :c:func:`exec` will be called immediately
after.
High-level APIs
---------------
These are the most commonly used types and functions when writing multi-threaded
C extensions.
.. c:type:: PyThreadState
This data structure represents the state of a single thread. The only public
data member is:
.. c:member:: PyInterpreterState *interp
This thread's interpreter state.
.. c:function:: void PyEval_InitThreads()
.. index::
single: PyEval_AcquireThread()
single: PyEval_ReleaseThread()
single: PyEval_SaveThread()
single: PyEval_RestoreThread()
Deprecated function which does nothing.
In Python 3.6 and older, this function created the GIL if it didn't exist.
.. versionchanged:: 3.9
The function now does nothing.
.. versionchanged:: 3.7
This function is now called by :c:func:`Py_Initialize()`, so you don't
have to call it yourself anymore.
.. versionchanged:: 3.2
This function cannot be called before :c:func:`Py_Initialize()` anymore.
.. deprecated:: 3.9
.. index:: pair: module; _thread
.. c:function:: PyThreadState* PyEval_SaveThread()
Detach the :term:`attached thread state` and return it.
The thread will have no :term:`thread state` upon returning.
.. c:function:: void PyEval_RestoreThread(PyThreadState *tstate)
Set the :term:`attached thread state` to *tstate*.
The passed :term:`thread state` **should not** be :term:`attached <attached thread state>`,
otherwise deadlock ensues. *tstate* will be attached upon returning.
.. note::
Calling this function from a thread when the runtime is finalizing will
hang the thread until the program exits, even if the thread was not
created by Python. Refer to
:ref:`cautions-regarding-runtime-finalization` for more details.
.. versionchanged:: 3.14
Hangs the current thread, rather than terminating it, if called while the
interpreter is finalizing.
.. c:function:: PyThreadState* PyThreadState_Get()
Return the :term:`attached thread state`. If the thread has no attached
thread state, (such as when inside of :c:macro:`Py_BEGIN_ALLOW_THREADS`
block), then this issues a fatal error (so that the caller needn't check
for ``NULL``).
See also :c:func:`PyThreadState_GetUnchecked`.
.. c:function:: PyThreadState* PyThreadState_GetUnchecked()
Similar to :c:func:`PyThreadState_Get`, but don't kill the process with a
fatal error if it is NULL. The caller is responsible to check if the result
is NULL.
.. versionadded:: 3.13
In Python 3.5 to 3.12, the function was private and known as
``_PyThreadState_UncheckedGet()``.
.. c:function:: PyThreadState* PyThreadState_Swap(PyThreadState *tstate)
Set the :term:`attached thread state` to *tstate*, and return the
:term:`thread state` that was attached prior to calling.
This function is safe to call without an :term:`attached thread state`; it
will simply return ``NULL`` indicating that there was no prior thread state.
.. seealso::
:c:func:`PyEval_ReleaseThread`
.. note::
Similar to :c:func:`PyGILState_Ensure`, this function will hang the
thread if the runtime is finalizing.
GIL-state APIs
--------------
The following functions use thread-local storage, and are not compatible
with sub-interpreters:
.. c:type:: PyGILState_STATE
The type of the value returned by :c:func:`PyGILState_Ensure` and passed to
:c:func:`PyGILState_Release`.
.. c:enumerator:: PyGILState_LOCKED
The GIL was already held when :c:func:`PyGILState_Ensure` was called.
.. c:enumerator:: PyGILState_UNLOCKED
The GIL was not held when :c:func:`PyGILState_Ensure` was called.
.. c:function:: PyGILState_STATE PyGILState_Ensure()
Ensure that the current thread is ready to call the Python C API regardless
of the current state of Python, or of the :term:`attached thread state`. This may
be called as many times as desired by a thread as long as each call is
matched with a call to :c:func:`PyGILState_Release`. In general, other
thread-related APIs may be used between :c:func:`PyGILState_Ensure` and
:c:func:`PyGILState_Release` calls as long as the thread state is restored to
its previous state before the Release(). For example, normal usage of the
:c:macro:`Py_BEGIN_ALLOW_THREADS` and :c:macro:`Py_END_ALLOW_THREADS` macros is
acceptable.
The return value is an opaque "handle" to the :term:`attached thread state` when
:c:func:`PyGILState_Ensure` was called, and must be passed to
:c:func:`PyGILState_Release` to ensure Python is left in the same state. Even
though recursive calls are allowed, these handles *cannot* be shared - each
unique call to :c:func:`PyGILState_Ensure` must save the handle for its call
to :c:func:`PyGILState_Release`.
When the function returns, there will be an :term:`attached thread state`
and the thread will be able to call arbitrary Python code. Failure is a fatal error.
.. warning::
Calling this function when the runtime is finalizing is unsafe. Doing
so will either hang the thread until the program ends, or fully crash
the interpreter in rare cases. Refer to
:ref:`cautions-regarding-runtime-finalization` for more details.
.. versionchanged:: 3.14
Hangs the current thread, rather than terminating it, if called while the
interpreter is finalizing.
.. c:function:: void PyGILState_Release(PyGILState_STATE)
Release any resources previously acquired. After this call, Python's state will
be the same as it was prior to the corresponding :c:func:`PyGILState_Ensure` call
(but generally this state will be unknown to the caller, hence the use of the
GILState API).
Every call to :c:func:`PyGILState_Ensure` must be matched by a call to
:c:func:`PyGILState_Release` on the same thread.
.. c:function:: PyThreadState* PyGILState_GetThisThreadState()
Get the :term:`attached thread state` for this thread. May return ``NULL`` if no
GILState API has been used on the current thread. Note that the main thread
always has such a thread-state, even if no auto-thread-state call has been
made on the main thread. This is mainly a helper/diagnostic function.
.. note::
This function may return non-``NULL`` even when the :term:`thread state`
is detached.
Prefer :c:func:`PyThreadState_Get` or :c:func:`PyThreadState_GetUnchecked`
for most cases.
.. seealso:: :c:func:`PyThreadState_Get`
.. c:function:: int PyGILState_Check()
Return ``1`` if the current thread is holding the :term:`GIL` and ``0`` otherwise.
This function can be called from any thread at any time.
Only if it has had its :term:`thread state <attached thread state>` initialized
via :c:func:`PyGILState_Ensure` will it return ``1``.
This is mainly a helper/diagnostic function. It can be useful
for example in callback contexts or memory allocation functions when
knowing that the :term:`GIL` is locked can allow the caller to perform sensitive
actions or otherwise behave differently.
.. note::
If the current Python process has ever created a subinterpreter, this
function will *always* return ``1``. Prefer :c:func:`PyThreadState_GetUnchecked`
for most cases.
.. versionadded:: 3.4
Low-level APIs
--------------
.. c:function:: PyThreadState* PyThreadState_New(PyInterpreterState *interp)
Create a new thread state object belonging to the given interpreter object.
An :term:`attached thread state` is not needed.
.. c:function:: void PyThreadState_Clear(PyThreadState *tstate)
Reset all information in a :term:`thread state` object. *tstate*
must be :term:`attached <attached thread state>`
.. versionchanged:: 3.9
This function now calls the :c:member:`!PyThreadState.on_delete` callback.
Previously, that happened in :c:func:`PyThreadState_Delete`.
.. versionchanged:: 3.13
The :c:member:`!PyThreadState.on_delete` callback was removed.
.. c:function:: void PyThreadState_Delete(PyThreadState *tstate)
Destroy a :term:`thread state` object. *tstate* should not
be :term:`attached <attached thread state>` to any thread.
*tstate* must have been reset with a previous call to
:c:func:`PyThreadState_Clear`.
.. c:function:: void PyThreadState_DeleteCurrent(void)
Detach the :term:`attached thread state` (which must have been reset
with a previous call to :c:func:`PyThreadState_Clear`) and then destroy it.
No :term:`thread state` will be :term:`attached <attached thread state>` upon
returning.
.. c:function:: PyFrameObject* PyThreadState_GetFrame(PyThreadState *tstate)
Get the current frame of the Python thread state *tstate*.
Return a :term:`strong reference`. Return ``NULL`` if no frame is currently
executing.
See also :c:func:`PyEval_GetFrame`.
*tstate* must not be ``NULL``, and must be :term:`attached <attached thread state>`.
.. versionadded:: 3.9
.. c:function:: uint64_t PyThreadState_GetID(PyThreadState *tstate)
Get the unique :term:`thread state` identifier of the Python thread state *tstate*.
*tstate* must not be ``NULL``, and must be :term:`attached <attached thread state>`.
.. versionadded:: 3.9
.. c:function:: PyInterpreterState* PyThreadState_GetInterpreter(PyThreadState *tstate)
Get the interpreter of the Python thread state *tstate*.
*tstate* must not be ``NULL``, and must be :term:`attached <attached thread state>`.
.. versionadded:: 3.9
.. c:function:: void PyThreadState_EnterTracing(PyThreadState *tstate)
Suspend tracing and profiling in the Python thread state *tstate*.
Resume them using the :c:func:`PyThreadState_LeaveTracing` function.
.. versionadded:: 3.11
.. c:function:: void PyThreadState_LeaveTracing(PyThreadState *tstate)
Resume tracing and profiling in the Python thread state *tstate* suspended
by the :c:func:`PyThreadState_EnterTracing` function.
See also :c:func:`PyEval_SetTrace` and :c:func:`PyEval_SetProfile`
functions.
.. versionadded:: 3.11
.. c:function:: int PyUnstable_ThreadState_SetStackProtection(PyThreadState *tstate, void *stack_start_addr, size_t stack_size)
Set the stack protection start address and stack protection size
of a Python thread state.
On success, return ``0``.
On failure, set an exception and return ``-1``.
CPython implements :ref:`recursion control <recursion>` for C code by raising
:py:exc:`RecursionError` when it notices that the machine execution stack is close
to overflow. See for example the :c:func:`Py_EnterRecursiveCall` function.
For this, it needs to know the location of the current thread's stack, which it
normally gets from the operating system.
When the stack is changed, for example using context switching techniques like the
Boost library's ``boost::context``, you must call
:c:func:`~PyUnstable_ThreadState_SetStackProtection` to inform CPython of the change.
Call :c:func:`~PyUnstable_ThreadState_SetStackProtection` either before
or after changing the stack.
Do not call any other Python C API between the call and the stack
change.
See :c:func:`PyUnstable_ThreadState_ResetStackProtection` for undoing this operation.
.. versionadded:: 3.15
.. c:function:: void PyUnstable_ThreadState_ResetStackProtection(PyThreadState *tstate)
Reset the stack protection start address and stack protection size
of a Python thread state to the operating system defaults.
See :c:func:`PyUnstable_ThreadState_SetStackProtection` for an explanation.
.. versionadded:: 3.15
.. c:function:: PyObject* PyThreadState_GetDict()
Return a dictionary in which extensions can store thread-specific state
information. Each extension should use a unique key to use to store state in
the dictionary. It is okay to call this function when no :term:`thread state`
is :term:`attached <attached thread state>`. If this function returns
``NULL``, no exception has been raised and the caller should assume no
thread state is attached.
.. c:function:: void PyEval_AcquireThread(PyThreadState *tstate)
:term:`Attach <attached thread state>` *tstate* to the current thread,
which must not be ``NULL`` or already :term:`attached <attached thread state>`.
The calling thread must not already have an :term:`attached thread state`.
.. note::
Calling this function from a thread when the runtime is finalizing will
hang the thread until the program exits, even if the thread was not
created by Python. Refer to
:ref:`cautions-regarding-runtime-finalization` for more details.
.. versionchanged:: 3.8
Updated to be consistent with :c:func:`PyEval_RestoreThread`,
:c:func:`Py_END_ALLOW_THREADS`, and :c:func:`PyGILState_Ensure`,
and terminate the current thread if called while the interpreter is finalizing.
.. versionchanged:: 3.14
Hangs the current thread, rather than terminating it, if called while the
interpreter is finalizing.
:c:func:`PyEval_RestoreThread` is a higher-level function which is always
available (even when threads have not been initialized).
.. c:function:: void PyEval_ReleaseThread(PyThreadState *tstate)
Detach the :term:`attached thread state`.
The *tstate* argument, which must not be ``NULL``, is only used to check
that it represents the :term:`attached thread state` --- if it isn't, a fatal error is
reported.
:c:func:`PyEval_SaveThread` is a higher-level function which is always
available (even when threads have not been initialized).
Asynchronous notifications
==========================
A mechanism is provided to make asynchronous notifications to the main
interpreter thread. These notifications take the form of a function
pointer and a void pointer argument.
.. c:function:: int Py_AddPendingCall(int (*func)(void *), void *arg)
Schedule a function to be called from the main interpreter thread. On
success, ``0`` is returned and *func* is queued for being called in the
main thread. On failure, ``-1`` is returned without setting any exception.
When successfully queued, *func* will be *eventually* called from the
main interpreter thread with the argument *arg*. It will be called
asynchronously with respect to normally running Python code, but with
both these conditions met:
* on a :term:`bytecode` boundary;
* with the main thread holding an :term:`attached thread state`
(*func* can therefore use the full C API).
*func* must return ``0`` on success, or ``-1`` on failure with an exception
set. *func* won't be interrupted to perform another asynchronous
notification recursively, but it can still be interrupted to switch
threads if the :term:`thread state <attached thread state>` is detached.
This function doesn't need an :term:`attached thread state`. However, to call this
function in a subinterpreter, the caller must have an :term:`attached thread state`.
Otherwise, the function *func* can be scheduled to be called from the wrong interpreter.
.. warning::
This is a low-level function, only useful for very special cases.
There is no guarantee that *func* will be called as quick as
possible. If the main thread is busy executing a system call,
*func* won't be called before the system call returns. This
function is generally **not** suitable for calling Python code from
arbitrary C threads. Instead, use the :ref:`PyGILState API<gilstate>`.
.. versionadded:: 3.1
.. versionchanged:: 3.9
If this function is called in a subinterpreter, the function *func* is
now scheduled to be called from the subinterpreter, rather than being
called from the main interpreter. Each subinterpreter now has its own
list of scheduled calls.
.. versionchanged:: 3.12
This function now always schedules *func* to be run in the main
interpreter.
.. c:function:: int Py_MakePendingCalls(void)
Execute all pending calls. This is usually executed automatically by the
interpreter.
This function returns ``0`` on success, and returns ``-1`` with an exception
set on failure.
If this is not called in the main thread of the main
interpreter, this function does nothing and returns ``0``.
The caller must hold an :term:`attached thread state`.
.. versionadded:: 3.1
.. versionchanged:: 3.12
This function only runs pending calls in the main interpreter.
.. c:function:: int PyThreadState_SetAsyncExc(unsigned long id, PyObject *exc)
Schedule an exception to be raised asynchronously in a thread.
If the thread has a previously scheduled exception, it is overwritten.
The *id* argument is the thread id of the target thread, as returned by
:c:func:`PyThread_get_thread_ident`.
*exc* is the class of the exception to be raised, or ``NULL`` to clear
the pending exception (if any).
Return the number of affected thread states.
This is normally ``1`` if *id* is found, even when no change was
made (the given *exc* was already pending, or *exc* is ``NULL`` but
no exception is pending).
If the thread id isn't found, return ``0``. This raises no exceptions.
To prevent naive misuse, you must write your own C extension to call this.
This function must be called with an :term:`attached thread state`.
This function does not steal any references to *exc*.
This function does not necessarily interrupt system calls such as
:py:func:`~time.sleep`.
.. versionchanged:: 3.7
The type of the *id* parameter changed from :c:expr:`long` to
:c:expr:`unsigned long`.
Operating system thread APIs
============================
.. c:macro:: PYTHREAD_INVALID_THREAD_ID
Sentinel value for an invalid thread ID.
This is currently equivalent to ``(unsigned long)-1``.
.. c:function:: unsigned long PyThread_start_new_thread(void (*func)(void *), void *arg)
Start function *func* in a new thread with argument *arg*.
The resulting thread is not intended to be joined.
*func* must not be ``NULL``, but *arg* may be ``NULL``.
On success, this function returns the identifier of the new thread; on failure,
this returns :c:macro:`PYTHREAD_INVALID_THREAD_ID`.
The caller does not need to hold an :term:`attached thread state`.
.. c:function:: unsigned long PyThread_get_thread_ident(void)
Return the identifier of the current thread, which will never be zero.
This function cannot fail, and the caller does not need to hold an
:term:`attached thread state`.
.. seealso::
:py:func:`threading.get_ident` and :py:attr:`threading.Thread.ident`
expose this identifier to Python.
.. c:function:: PyObject *PyThread_GetInfo(void)
Get general information about the current thread in the form of a
:ref:`struct sequence <struct-sequence-objects>` object. This information is
accessible as :py:attr:`sys.thread_info` in Python.
On success, this returns a new :term:`strong reference` to the thread
information; on failure, this returns ``NULL`` with an exception set.
The caller must hold an :term:`attached thread state`.
.. c:macro:: PY_HAVE_THREAD_NATIVE_ID
This macro is defined when the system supports native thread IDs.
.. c:function:: unsigned long PyThread_get_thread_native_id(void)
Get the native identifier of the current thread as it was assigned by the operating
system's kernel, which will never be less than zero.
This function is only available when :c:macro:`PY_HAVE_THREAD_NATIVE_ID` is
defined.
This function cannot fail, and the caller does not need to hold an
:term:`attached thread state`.
.. seealso::
:py:func:`threading.get_native_id`
.. c:function:: void PyThread_exit_thread(void)
Terminate the current thread. This function is generally considered unsafe
and should be avoided. It is kept solely for backwards compatibility.
This function is only safe to call if all functions in the full call
stack are written to safely allow it.
.. warning::
If the current system uses POSIX threads (also known as "pthreads"),
this calls :manpage:`pthread_exit(3)`, which attempts to unwind the stack
and call C++ destructors on some libc implementations. However, if a
``noexcept`` function is reached, it may terminate the process.
Other systems, such as macOS, do unwinding.
On Windows, this function calls ``_endthreadex()``, which kills the thread
without calling C++ destructors.
In any case, there is a risk of corruption on the thread's stack.
.. deprecated:: 3.14
.. c:function:: void PyThread_init_thread(void)
Initialize ``PyThread*`` APIs. Python executes this function automatically,
so there's little need to call it from an extension module.
.. c:function:: int PyThread_set_stacksize(size_t size)
Set the stack size of the current thread to *size* bytes.
This function returns ``0`` on success, ``-1`` if *size* is invalid, or
``-2`` if the system does not support changing the stack size. This function
does not set exceptions.
The caller does not need to hold an :term:`attached thread state`.
.. c:function:: size_t PyThread_get_stacksize(void)
Return the stack size of the current thread in bytes, or ``0`` if the system's
default stack size is in use.
The caller does not need to hold an :term:`attached thread state`.

155
Doc/c-api/tls.rst Normal file
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@ -0,0 +1,155 @@
.. highlight:: c
.. _thread-local-storage:
Thread-local storage support
============================
The Python interpreter provides low-level support for thread-local storage
(TLS) which wraps the underlying native TLS implementation to support the
Python-level thread-local storage API (:class:`threading.local`). The
CPython C level APIs are similar to those offered by pthreads and Windows:
use a thread key and functions to associate a :c:expr:`void*` value per
thread.
A :term:`thread state` does *not* need to be :term:`attached <attached thread state>`
when calling these functions; they supply their own locking.
Note that :file:`Python.h` does not include the declaration of the TLS APIs,
you need to include :file:`pythread.h` to use thread-local storage.
.. note::
None of these API functions handle memory management on behalf of the
:c:expr:`void*` values. You need to allocate and deallocate them yourself.
If the :c:expr:`void*` values happen to be :c:expr:`PyObject*`, these
functions don't do refcount operations on them either.
.. _thread-specific-storage-api:
Thread-specific storage API
---------------------------
The thread-specific storage (TSS) API was introduced to supersede the use of the existing TLS API within the
CPython interpreter. This API uses a new type :c:type:`Py_tss_t` instead of
:c:expr:`int` to represent thread keys.
.. versionadded:: 3.7
.. seealso:: "A New C-API for Thread-Local Storage in CPython" (:pep:`539`)
.. c:type:: Py_tss_t
This data structure represents the state of a thread key, the definition of
which may depend on the underlying TLS implementation, and it has an
internal field representing the key's initialization state. There are no
public members in this structure.
When :ref:`Py_LIMITED_API <stable>` is not defined, static allocation of
this type by :c:macro:`Py_tss_NEEDS_INIT` is allowed.
.. c:macro:: Py_tss_NEEDS_INIT
This macro expands to the initializer for :c:type:`Py_tss_t` variables.
Note that this macro won't be defined with :ref:`Py_LIMITED_API <stable>`.
Dynamic allocation
------------------
Dynamic allocation of the :c:type:`Py_tss_t`, required in extension modules
built with :ref:`Py_LIMITED_API <stable>`, where static allocation of this type
is not possible due to its implementation being opaque at build time.
.. c:function:: Py_tss_t* PyThread_tss_alloc()
Return a value which is the same state as a value initialized with
:c:macro:`Py_tss_NEEDS_INIT`, or ``NULL`` in the case of dynamic allocation
failure.
.. c:function:: void PyThread_tss_free(Py_tss_t *key)
Free the given *key* allocated by :c:func:`PyThread_tss_alloc`, after
first calling :c:func:`PyThread_tss_delete` to ensure any associated
thread locals have been unassigned. This is a no-op if the *key*
argument is ``NULL``.
.. note::
A freed key becomes a dangling pointer. You should reset the key to
``NULL``.
Methods
-------
The parameter *key* of these functions must not be ``NULL``. Moreover, the
behaviors of :c:func:`PyThread_tss_set` and :c:func:`PyThread_tss_get` are
undefined if the given :c:type:`Py_tss_t` has not been initialized by
:c:func:`PyThread_tss_create`.
.. c:function:: int PyThread_tss_is_created(Py_tss_t *key)
Return a non-zero value if the given :c:type:`Py_tss_t` has been initialized
by :c:func:`PyThread_tss_create`.
.. c:function:: int PyThread_tss_create(Py_tss_t *key)
Return a zero value on successful initialization of a TSS key. The behavior
is undefined if the value pointed to by the *key* argument is not
initialized by :c:macro:`Py_tss_NEEDS_INIT`. This function can be called
repeatedly on the same key -- calling it on an already initialized key is a
no-op and immediately returns success.
.. c:function:: void PyThread_tss_delete(Py_tss_t *key)
Destroy a TSS key to forget the values associated with the key across all
threads, and change the key's initialization state to uninitialized. A
destroyed key is able to be initialized again by
:c:func:`PyThread_tss_create`. This function can be called repeatedly on
the same key -- calling it on an already destroyed key is a no-op.
.. c:function:: int PyThread_tss_set(Py_tss_t *key, void *value)
Return a zero value to indicate successfully associating a :c:expr:`void*`
value with a TSS key in the current thread. Each thread has a distinct
mapping of the key to a :c:expr:`void*` value.
.. c:function:: void* PyThread_tss_get(Py_tss_t *key)
Return the :c:expr:`void*` value associated with a TSS key in the current
thread. This returns ``NULL`` if no value is associated with the key in the
current thread.
.. _thread-local-storage-api:
Legacy APIs
-----------
.. deprecated:: 3.7
This API is superseded by the
:ref:`thread-specific storage (TSS) API <thread-specific-storage-api>`.
.. note::
This version of the API does not support platforms where the native TLS key
is defined in a way that cannot be safely cast to ``int``. On such platforms,
:c:func:`PyThread_create_key` will return immediately with a failure status,
and the other TLS functions will all be no-ops on such platforms.
Due to the compatibility problem noted above, this version of the API should not
be used in new code.
.. c:function:: int PyThread_create_key()
.. c:function:: void PyThread_delete_key(int key)
.. c:function:: int PyThread_set_key_value(int key, void *value)
.. c:function:: void* PyThread_get_key_value(int key)
.. c:function:: void PyThread_delete_key_value(int key)
.. c:function:: void PyThread_ReInitTLS()

7
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@ -99,7 +99,8 @@ Tuple Objects
Insert a reference to object *o* at position *pos* of the tuple pointed to by
*p*. Return ``0`` on success. If *pos* is out of bounds, return ``-1``
and set an :exc:`IndexError` exception.
and set an :exc:`IndexError` exception. This function should only be used to fill in brand new tuples;
using it on an existing tuple is thread-unsafe.
.. note::
@ -110,7 +111,7 @@ Tuple Objects
.. c:function:: void PyTuple_SET_ITEM(PyObject *p, Py_ssize_t pos, PyObject *o)
Like :c:func:`PyTuple_SetItem`, but does no error checking, and should *only* be
used to fill in brand new tuples.
used to fill in brand new tuples, using it on an existing tuple is thread-unsafe.
Bounds checking is performed as an assertion if Python is built in
:ref:`debug mode <debug-build>` or :option:`with assertions <--with-assertions>`.
@ -236,6 +237,8 @@ type.
.. c:function:: PyObject* PyStructSequence_GetItem(PyObject *p, Py_ssize_t pos)
Return the object at position *pos* in the struct sequence pointed to by *p*.
The returned reference is borrowed from the struct sequence *p*
(that is: it is only valid as long as you hold a reference to *p*).
Bounds checking is performed as an assertion if Python is built in
:ref:`debug mode <debug-build>` or :option:`with assertions <--with-assertions>`.

4
Doc/c-api/type.rst
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@ -274,6 +274,10 @@ Type Objects
Return the module object associated with the given type when the type was
created using :c:func:`PyType_FromModuleAndSpec`.
The returned reference is :term:`borrowed <borrowed reference>` from *type*,
and will be valid as long as you hold a reference to *type*.
Do not release it with :c:func:`Py_DECREF` or similar.
If no module is associated with the given type, sets :py:class:`TypeError`
and returns ``NULL``.

183
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@ -1391,8 +1391,8 @@ and :c:data:`PyType_Type` effectively act as defaults.)
.. versionchanged:: 3.9
Renamed to the current name, without the leading underscore.
The old provisional name is :term:`soft deprecated`.
Renamed to the current name, without the leading underscore.
The old provisional name is :term:`soft deprecated`.
.. versionchanged:: 3.12
@ -1499,6 +1499,54 @@ and :c:data:`PyType_Type` effectively act as defaults.)
It will be removed in a future version of CPython
.. c:macro:: Py_TPFLAGS_HAVE_VERSION_TAG
This macro does nothing.
Historically, this would indicate that the
:c:member:`~PyTypeObject.tp_version_tag` field was available and
initialized.
.. soft-deprecated:: 3.13
.. c:macro:: Py_TPFLAGS_INLINE_VALUES
This bit indicates that instances of this type will have an "inline values"
array (containing the object's attributes) placed directly after the end
of the object.
This requires that :c:macro:`Py_TPFLAGS_HAVE_GC` is set.
**Inheritance:**
This flag is not inherited.
.. versionadded:: 3.13
.. c:macro:: Py_TPFLAGS_IS_ABSTRACT
This bit indicates that this is an abstract type and therefore cannot
be instantiated.
**Inheritance:**
This flag is not inherited.
.. seealso::
:mod:`abc`
.. c:macro:: Py_TPFLAGS_HAVE_STACKLESS_EXTENSION
Internal. Do not set or unset this flag.
Historically, this was a reserved flag for use in Stackless Python.
.. warning::
This flag is present in header files, but is not be used.
This may be removed in a future version of CPython.
.. c:member:: const char* PyTypeObject.tp_doc
.. corresponding-type-slot:: Py_tp_doc
@ -1517,93 +1565,9 @@ and :c:data:`PyType_Type` effectively act as defaults.)
.. corresponding-type-slot:: Py_tp_traverse
An optional pointer to a traversal function for the garbage collector. This is
only used if the :c:macro:`Py_TPFLAGS_HAVE_GC` flag bit is set. The signature is::
only used if the :c:macro:`Py_TPFLAGS_HAVE_GC` flag bit is set.
int tp_traverse(PyObject *self, visitproc visit, void *arg);
More information about Python's garbage collection scheme can be found
in section :ref:`supporting-cycle-detection`.
The :c:member:`~PyTypeObject.tp_traverse` pointer is used by the garbage collector to detect
reference cycles. A typical implementation of a :c:member:`~PyTypeObject.tp_traverse` function
simply calls :c:func:`Py_VISIT` on each of the instance's members that are Python
objects that the instance owns. For example, this is function :c:func:`!local_traverse` from the
:mod:`!_thread` extension module::
static int
local_traverse(PyObject *op, visitproc visit, void *arg)
{
localobject *self = (localobject *) op;
Py_VISIT(self->args);
Py_VISIT(self->kw);
Py_VISIT(self->dict);
return 0;
}
Note that :c:func:`Py_VISIT` is called only on those members that can participate
in reference cycles. Although there is also a ``self->key`` member, it can only
be ``NULL`` or a Python string and therefore cannot be part of a reference cycle.
On the other hand, even if you know a member can never be part of a cycle, as a
debugging aid you may want to visit it anyway just so the :mod:`gc` module's
:func:`~gc.get_referents` function will include it.
Heap types (:c:macro:`Py_TPFLAGS_HEAPTYPE`) must visit their type with::
Py_VISIT(Py_TYPE(self));
It is only needed since Python 3.9. To support Python 3.8 and older, this
line must be conditional::
#if PY_VERSION_HEX >= 0x03090000
Py_VISIT(Py_TYPE(self));
#endif
If the :c:macro:`Py_TPFLAGS_MANAGED_DICT` bit is set in the
:c:member:`~PyTypeObject.tp_flags` field, the traverse function must call
:c:func:`PyObject_VisitManagedDict` like this::
PyObject_VisitManagedDict((PyObject*)self, visit, arg);
.. warning::
When implementing :c:member:`~PyTypeObject.tp_traverse`, only the
members that the instance *owns* (by having :term:`strong references
<strong reference>` to them) must be
visited. For instance, if an object supports weak references via the
:c:member:`~PyTypeObject.tp_weaklist` slot, the pointer supporting
the linked list (what *tp_weaklist* points to) must **not** be
visited as the instance does not directly own the weak references to itself
(the weakreference list is there to support the weak reference machinery,
but the instance has no strong reference to the elements inside it, as they
are allowed to be removed even if the instance is still alive).
.. warning::
The traversal function must not have any side effects. It must not
modify the reference counts of any Python objects nor create or destroy
any Python objects.
Note that :c:func:`Py_VISIT` requires the *visit* and *arg* parameters to
:c:func:`!local_traverse` to have these specific names; don't name them just
anything.
Instances of :ref:`heap-allocated types <heap-types>` hold a reference to
their type. Their traversal function must therefore either visit
:c:func:`Py_TYPE(self) <Py_TYPE>`, or delegate this responsibility by
calling ``tp_traverse`` of another heap-allocated type (such as a
heap-allocated superclass).
If they do not, the type object may not be garbage-collected.
.. note::
The :c:member:`~PyTypeObject.tp_traverse` function can be called from any
thread.
.. versionchanged:: 3.9
Heap-allocated types are expected to visit ``Py_TYPE(self)`` in
``tp_traverse``. In earlier versions of Python, due to
`bug 40217 <https://bugs.python.org/issue40217>`_, doing this
may lead to crashes in subclasses.
See :ref:`gc-traversal` for documentation.
**Inheritance:**
@ -2632,9 +2596,6 @@ This is done by filling a :c:type:`PyType_Spec` structure and calling
Number Object Structures
------------------------
.. sectionauthor:: Amaury Forgeot d'Arc
.. c:type:: PyNumberMethods
This structure holds pointers to the functions which an object uses to
@ -2852,9 +2813,6 @@ Number Object Structures
Mapping Object Structures
-------------------------
.. sectionauthor:: Amaury Forgeot d'Arc
.. c:type:: PyMappingMethods
This structure holds pointers to the functions which an object uses to
@ -2895,9 +2853,6 @@ Mapping Object Structures
Sequence Object Structures
--------------------------
.. sectionauthor:: Amaury Forgeot d'Arc
.. c:type:: PySequenceMethods
This structure holds pointers to the functions which an object uses to
@ -2991,10 +2946,6 @@ Sequence Object Structures
Buffer Object Structures
------------------------
.. sectionauthor:: Greg J. Stein <greg@lyra.org>
.. sectionauthor:: Benjamin Peterson
.. sectionauthor:: Stefan Krah
.. c:type:: PyBufferProcs
This structure holds pointers to the functions required by the
@ -3024,6 +2975,24 @@ Buffer Object Structures
(5) Return ``0``.
**Thread safety:**
In the :term:`free-threaded build`, implementations must ensure:
* The export counter increment in step (3) is atomic.
* The underlying buffer data remains valid and at a stable memory
location for the lifetime of all exports.
* For objects that support resizing or reallocation (such as
:class:`bytearray`), the export counter is checked atomically before
such operations, and :exc:`BufferError` is raised if exports exist.
* The function is safe to call concurrently from multiple threads.
See also :ref:`thread-safety-memoryview` for the Python-level
thread safety guarantees of :class:`memoryview` objects.
If *exporter* is part of a chain or tree of buffer providers, two main
schemes can be used:
@ -3069,6 +3038,16 @@ Buffer Object Structures
(2) If the counter is ``0``, free all memory associated with *view*.
**Thread safety:**
In the :term:`free-threaded build`:
* The export counter decrement in step (1) must be atomic.
* Resource cleanup when the counter reaches zero must be done atomically,
as the final release may race with concurrent releases from other
threads and dellocation must only happen once.
The exporter MUST use the :c:member:`~Py_buffer.internal` field to keep
track of buffer-specific resources. This field is guaranteed to remain
constant, while a consumer MAY pass a copy of the original buffer as the
@ -3090,8 +3069,6 @@ Buffer Object Structures
Async Object Structures
-----------------------
.. sectionauthor:: Yury Selivanov <yselivanov@sprymix.com>
.. versionadded:: 3.5
.. c:type:: PyAsyncMethods

17
Doc/c-api/unicode.rst
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@ -5,9 +5,6 @@
Unicode Objects and Codecs
--------------------------
.. sectionauthor:: Marc-André Lemburg <mal@lemburg.com>
.. sectionauthor:: Georg Brandl <georg@python.org>
Unicode Objects
^^^^^^^^^^^^^^^
@ -1858,8 +1855,6 @@ object.
On success, return ``0``.
On error, set an exception, leave the writer unchanged, and return ``-1``.
.. versionadded:: 3.14
.. c:function:: int PyUnicodeWriter_WriteWideChar(PyUnicodeWriter *writer, const wchar_t *str, Py_ssize_t size)
Write the wide string *str* into *writer*.
@ -1870,7 +1865,7 @@ object.
On success, return ``0``.
On error, set an exception, leave the writer unchanged, and return ``-1``.
.. c:function:: int PyUnicodeWriter_WriteUCS4(PyUnicodeWriter *writer, Py_UCS4 *str, Py_ssize_t size)
.. c:function:: int PyUnicodeWriter_WriteUCS4(PyUnicodeWriter *writer, const Py_UCS4 *str, Py_ssize_t size)
Writer the UCS4 string *str* into *writer*.
@ -1886,13 +1881,23 @@ object.
On success, return ``0``.
On error, set an exception, leave the writer unchanged, and return ``-1``.
To write a :class:`str` subclass which overrides the :meth:`~object.__str__`
method, :c:func:`PyUnicode_FromObject` can be used to get the original
string.
.. c:function:: int PyUnicodeWriter_WriteRepr(PyUnicodeWriter *writer, PyObject *obj)
Call :c:func:`PyObject_Repr` on *obj* and write the output into *writer*.
If *obj* is ``NULL``, write the string ``"<NULL>"`` into *writer*.
On success, return ``0``.
On error, set an exception, leave the writer unchanged, and return ``-1``.
.. versionchanged:: 3.14.4
Added support for ``NULL``.
.. c:function:: int PyUnicodeWriter_WriteSubstring(PyUnicodeWriter *writer, PyObject *str, Py_ssize_t start, Py_ssize_t end)
Write the substring ``str[start:end]`` into *writer*.

2
Doc/c-api/veryhigh.rst
View file

@ -191,7 +191,7 @@ the same library that the Python runtime is using.
objects *globals* and *locals* with the compiler flags specified by
*flags*. *globals* must be a dictionary; *locals* can be any object
that implements the mapping protocol. The parameter *start* specifies
the start symbol and must one of the :ref:`available start symbols <start-symbols>`.
the start symbol and must be one of the :ref:`available start symbols <start-symbols>`.
Returns the result of executing the code as a Python object, or ``NULL`` if an
exception was raised.

51
Doc/conf.py
View file

@ -33,6 +33,7 @@
'issue_role',
'lexers',
'misc_news',
'profiling_trace',
'pydoc_topics',
'pyspecific',
'sphinx.ext.coverage',
@ -42,8 +43,10 @@
# Skip if downstream redistributors haven't installed them
_OPTIONAL_EXTENSIONS = (
'linklint.ext',
'notfound.extension',
'sphinxext.opengraph',
'sphinxcontrib.rsvgconverter',
)
for optional_ext in _OPTIONAL_EXTENSIONS:
try:
@ -70,6 +73,7 @@
# General substitutions.
project = 'Python'
copyright = "2001 Python Software Foundation"
_doc_authors = 'Python documentation authors'
# We look for the Include/patchlevel.h file in the current Python source tree
# and replace the values accordingly.
@ -174,6 +178,7 @@
('c:type', '__int64'),
('c:type', 'unsigned __int64'),
('c:type', 'double'),
('c:type', '_Float16'),
# Standard C structures
('c:struct', 'in6_addr'),
('c:struct', 'in_addr'),
@ -226,10 +231,6 @@
# Temporary undocumented names.
# In future this list must be empty.
nitpick_ignore += [
# Do not error nit-picky mode builds when _SubParsersAction.add_parser cannot
# be resolved, as the method is currently undocumented. For context, see
# https://github.com/python/cpython/pull/103289.
('py:meth', '_SubParsersAction.add_parser'),
# Attributes/methods/etc. that definitely should be documented better,
# but are deferred for now:
('py:attr', '__wrapped__'),
@ -361,69 +362,74 @@
# Grouping the document tree into LaTeX files. List of tuples
# (source start file, target name, title, author, document class [howto/manual]).
_stdauthor = 'The Python development team'
latex_documents = [
('c-api/index', 'c-api.tex', 'The Python/C API', _stdauthor, 'manual'),
('c-api/index', 'c-api.tex', 'The Python/C API', _doc_authors, 'manual'),
(
'extending/index',
'extending.tex',
'Extending and Embedding Python',
_stdauthor,
_doc_authors,
'manual',
),
(
'installing/index',
'installing.tex',
'Installing Python Modules',
_stdauthor,
_doc_authors,
'manual',
),
(
'library/index',
'library.tex',
'The Python Library Reference',
_stdauthor,
_doc_authors,
'manual',
),
(
'reference/index',
'reference.tex',
'The Python Language Reference',
_stdauthor,
_doc_authors,
'manual',
),
(
'tutorial/index',
'tutorial.tex',
'Python Tutorial',
_stdauthor,
_doc_authors,
'manual',
),
(
'using/index',
'using.tex',
'Python Setup and Usage',
_stdauthor,
_doc_authors,
'manual',
),
(
'faq/index',
'faq.tex',
'Python Frequently Asked Questions',
_stdauthor,
_doc_authors,
'manual',
),
(
'whatsnew/' + version,
'whatsnew.tex',
'What\'s New in Python',
'A. M. Kuchling',
_doc_authors,
'howto',
),
]
# Collect all HOWTOs individually
latex_documents.extend(
('howto/' + fn[:-4], 'howto-' + fn[:-4] + '.tex', '', _stdauthor, 'howto')
(
'howto/' + fn[:-4],
'howto-' + fn[:-4] + '.tex',
'',
_doc_authors,
'howto',
)
for fn in os.listdir('howto')
if fn.endswith('.rst') and fn != 'index.rst'
)
@ -434,7 +440,7 @@
# Options for Epub output
# -----------------------
epub_author = 'Python Documentation Authors'
epub_author = _doc_authors
epub_publisher = 'Python Software Foundation'
epub_exclude_files = (
'index.xhtml',
@ -558,6 +564,7 @@
# mapping unique short aliases to a base URL and a prefix.
# https://www.sphinx-doc.org/en/master/usage/extensions/extlinks.html
extlinks = {
"oss-fuzz": ("https://issues.oss-fuzz.com/issues/%s", "#%s"),
"pypi": ("https://pypi.org/project/%s/", "%s"),
"source": (SOURCE_URI, "%s"),
}
@ -569,6 +576,18 @@
# Relative filename of the data files
refcount_file = 'data/refcounts.dat'
stable_abi_file = 'data/stable_abi.dat'
threadsafety_file = 'data/threadsafety.dat'
# Options for notfound.extension
# -------------------------------
if not os.getenv("READTHEDOCS"):
if language_code:
notfound_urls_prefix = (
f'/{language_code.replace("_", "-").lower()}/{version}/'
)
else:
notfound_urls_prefix = f'/{version}/'
# Options for sphinxext-opengraph
# -------------------------------

10
Doc/data/refcounts.dat
View file

@ -2427,10 +2427,20 @@ PyType_GetFlags:PyTypeObject*:type:0:
PyType_GetName:PyObject*::+1:
PyType_GetName:PyTypeObject*:type:0:
PyType_GetModule:PyObject*::0:
PyType_GetModule:PyTypeObject*:type:0:
PyType_GetModule_DuringGC:PyObject*::0:
PyType_GetModule_DuringGC:PyTypeObject*:type:0:
PyType_GetModuleByToken:PyObject*::+1:
PyType_GetModuleByToken:PyTypeObject*:type:0:
PyType_GetModuleByToken:PyModuleDef*:def::
PyType_GetModuleByToken_DuringGC:PyObject*::0:
PyType_GetModuleByToken_DuringGC:PyTypeObject*:type:0:
PyType_GetModuleByToken_DuringGC:PyModuleDef*:mod_token::
PyType_GetModuleByDef:PyObject*::0:
PyType_GetModuleByDef:PyTypeObject*:type:0:
PyType_GetModuleByDef:PyModuleDef*:def::

11
Doc/data/stable_abi.dat generated
View file

@ -470,8 +470,8 @@ func,PyMemoryView_GetContiguous,3.2,,
data,PyMemoryView_Type,3.2,,
type,PyMethodDef,3.2,,full-abi
data,PyMethodDescr_Type,3.2,,
type,PyModuleDef,3.2,,full-abi
type,PyModuleDef_Base,3.2,,full-abi
type,PyModuleDef,3.2,,abi3t-opaque
type,PyModuleDef_Base,3.2,,abi3t-opaque
func,PyModuleDef_Init,3.5,,
type,PyModuleDef_Slot,3.5,,full-abi
data,PyModuleDef_Type,3.5,,
@ -495,7 +495,9 @@ func,PyModule_GetName,3.2,,
func,PyModule_GetNameObject,3.7,,
func,PyModule_GetState,3.2,,
func,PyModule_GetStateSize,3.15,,
func,PyModule_GetState_DuringGC,3.15,,
func,PyModule_GetToken,3.15,,
func,PyModule_GetToken_DuringGC,3.15,,
func,PyModule_New,3.2,,
func,PyModule_NewObject,3.7,,
func,PyModule_SetDocString,3.7,,
@ -598,6 +600,7 @@ func,PyObject_GetIter,3.2,,
func,PyObject_GetOptionalAttr,3.13,,
func,PyObject_GetOptionalAttrString,3.13,,
func,PyObject_GetTypeData,3.12,,
func,PyObject_GetTypeData_DuringGC,3.15,,
func,PyObject_HasAttr,3.2,,
func,PyObject_HasAttrString,3.2,,
func,PyObject_HasAttrStringWithError,3.13,,
@ -750,13 +753,17 @@ func,PyType_FromSpecWithBases,3.3,,
func,PyType_GenericAlloc,3.2,,
func,PyType_GenericNew,3.2,,
func,PyType_GetBaseByToken,3.14,,
func,PyType_GetBaseByToken_DuringGC,3.15,,
func,PyType_GetFlags,3.2,,
func,PyType_GetFullyQualifiedName,3.13,,
func,PyType_GetModule,3.10,,
func,PyType_GetModuleByDef,3.13,,
func,PyType_GetModuleByToken,3.15,,
func,PyType_GetModuleByToken_DuringGC,3.15,,
func,PyType_GetModuleName,3.13,,
func,PyType_GetModuleState,3.10,,
func,PyType_GetModuleState_DuringGC,3.15,,
func,PyType_GetModule_DuringGC,3.15,,
func,PyType_GetName,3.11,,
func,PyType_GetQualName,3.11,,
func,PyType_GetSlot,3.4,,

284
Doc/data/threadsafety.dat Normal file
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@ -0,0 +1,284 @@
# Thread safety annotations for C API functions.
#
# Each line has the form:
# function_name : level
#
# Where level is one of:
# incompatible -- not safe even with external locking
# compatible -- safe if the caller serializes all access with external locks
# distinct -- safe on distinct objects without external synchronization
# shared -- safe for concurrent use on the same object
# atomic -- atomic
#
# Lines beginning with '#' are ignored.
# The function name must match the C domain identifier used in the documentation.
# Synchronization primitives (Doc/c-api/synchronization.rst)
PyMutex_Lock:atomic:
PyMutex_Unlock:atomic:
PyMutex_IsLocked:atomic:
# Dictionary objects (Doc/c-api/dict.rst)
# Type checks - read ob_type pointer, always safe
PyDict_Check:atomic:
PyDict_CheckExact:atomic:
# Creation - pure allocation, no shared state
PyDict_New:atomic:
# Lock-free lookups - use _Py_dict_lookup_threadsafe(), no locking.
# Atomic with simple types.
PyDict_Contains:shared:
PyDict_ContainsString:atomic:
PyDict_GetItemRef:shared:
PyDict_GetItemStringRef:atomic:
PyDict_Size:atomic:
PyDict_GET_SIZE:atomic:
# Borrowed-reference lookups - lock-free dict access but returned
# borrowed reference is unsafe in free-threaded builds without
# external synchronization
PyDict_GetItem:compatible:
PyDict_GetItemWithError:compatible:
PyDict_GetItemString:compatible:
PyDict_SetDefault:compatible:
# Iteration - no locking; returns borrowed refs
PyDict_Next:compatible:
# Single-item mutations - protected by per-object critical section
PyDict_SetItem:shared:
PyDict_SetItemString:atomic:
PyDict_DelItem:shared:
PyDict_DelItemString:atomic:
PyDict_SetDefaultRef:shared:
PyDict_Pop:shared:
PyDict_PopString:atomic:
# Bulk reads - hold per-object lock for duration
PyDict_Clear:atomic:
PyDict_Copy:atomic:
PyDict_Keys:atomic:
PyDict_Values:atomic:
PyDict_Items:atomic:
# Merge/update - lock target dict; also lock source when it is a dict
PyDict_Update:shared:
PyDict_Merge:shared:
PyDict_MergeFromSeq2:shared:
# Watcher registration - no synchronization on interpreter state
PyDict_AddWatcher:compatible:
PyDict_ClearWatcher:compatible:
# Per-dict watcher tags - non-atomic RMW on _ma_watcher_tag;
# safe on distinct dicts only
PyDict_Watch:distinct:
PyDict_Unwatch:distinct:
# List objects (Doc/c-api/list.rst)
# Type checks - read ob_type pointer, always safe
PyList_Check:atomic:
PyList_CheckExact:atomic:
# Creation - pure allocation, no shared state
PyList_New:atomic:
# Size - uses atomic load on free-threaded builds
PyList_Size:atomic:
PyList_GET_SIZE:atomic:
# Strong-reference lookup - lock-free with atomic ops
PyList_GetItemRef:atomic:
# Borrowed-reference lookups - no locking; returned borrowed
# reference is unsafe in free-threaded builds without
# external synchronization
PyList_GetItem:compatible:
PyList_GET_ITEM:compatible:
# Single-item mutations - hold per-object lock for duration;
# appear atomic to lock-free readers
PyList_SetItem:atomic:
PyList_Append:atomic:
# Insert - protected by per-object critical section; shifts
# elements so lock-free readers may observe intermediate states
PyList_Insert:shared:
# Initialization macro - no synchronization; normally only used
# to fill in new lists where there is no previous content
PyList_SET_ITEM:compatible:
# Bulk operations - hold per-object lock for duration
PyList_GetSlice:atomic:
PyList_AsTuple:atomic:
PyList_Clear:atomic:
# Reverse - protected by per-object critical section; swaps
# elements so lock-free readers may observe intermediate states
PyList_Reverse:shared:
# Slice assignment - lock target list; also lock source when it
# is a list
PyList_SetSlice:shared:
# Sort - per-object lock held; the list is emptied before sorting
# so other threads may observe an empty list, but they won't see the
# intermediate states of the sort
PyList_Sort:shared:
# Extend - lock target list; also lock source when it is a
# list, set, or dict
PyList_Extend:shared:
# Creation - pure allocation, no shared state
PyBytes_FromString:atomic:
PyBytes_FromStringAndSize:atomic:
PyBytes_DecodeEscape:atomic:
# Creation from formatting C primitives - pure allocation, no shared state
PyBytes_FromFormat:atomic:
PyBytes_FromFormatV:atomic:
# Creation from object - uses buffer protocol so may call arbitrary code;
# safe as long as the buffer is not mutated by another thread during the operation
PyBytes_FromObject:shared:
# Size - uses atomic load on free-threaded builds
PyBytes_Size:atomic:
PyBytes_GET_SIZE:atomic:
# Raw data - no locking; mutating it is unsafe if the bytes object is shared between threads
PyBytes_AsString:compatible:
PyBytes_AS_STRING:compatible:
PyBytes_AsStringAndSize:compatible:
# Concatenation - uses buffer protocol; safe as long as buffer is not mutated by another thread during the operation
PyBytes_Concat:shared:
PyBytes_ConcatAndDel:shared:
PyBytes_Join:shared:
# Resizing - safe if the object is unique
_PyBytes_Resize:distinct:
# Repr - atomic as bytes are immutable
PyBytes_Repr:atomic:
# Creation from object - may call arbitrary code
PyByteArray_FromObject:shared:
# Creation - pure allocation, no shared state
PyByteArray_FromStringAndSize:atomic:
# Concatenation - uses buffer protocol; safe as long as buffer is not mutated by another thread during the operation
PyByteArray_Concat:shared:
# Size - uses atomic load on free-threaded builds
PyByteArray_Size:atomic:
PyByteArray_GET_SIZE:atomic:
# Raw data - no locking; mutating it is unsafe if the bytearray object is shared between threads
PyByteArray_AsString:compatible:
PyByteArray_AS_STRING:compatible:
# Creation - may iterate the iterable argument, calling arbitrary code.
# Atomic for sets, frozensets, dicts, and frozendicts.
PySet_New:shared:
PyFrozenSet_New:shared:
# Size - uses atomic load on free-threaded builds
PySet_Size:atomic:
PySet_GET_SIZE:atomic:
# Contains - lock-free, atomic with simple types
PySet_Contains:shared:
# Mutations - hold per-object lock for duration
# atomic with simple types
PySet_Add:shared:
PySet_Discard:shared:
# Pop - hold per-object lock for duration
PySet_Pop:atomic:
# Clear - empties the set before clearing
PySet_Clear:atomic:
# Capsule objects (Doc/c-api/capsule.rst)
# Type check - read ob_type pointer, always safe
PyCapsule_CheckExact:atomic:
# Creation - pure allocation, no shared state
PyCapsule_New:atomic:
# Validation - reads pointer and name fields; safe on distinct objects
PyCapsule_IsValid:distinct:
# Getters - read struct fields; safe on distinct objects but
# concurrent access to the same capsule requires external synchronization
PyCapsule_GetPointer:distinct:
PyCapsule_GetName:distinct:
PyCapsule_GetDestructor:distinct:
PyCapsule_GetContext:distinct:
# Setters - write struct fields; safe on distinct objects but
# concurrent access to the same capsule requires external synchronization
PyCapsule_SetPointer:distinct:
PyCapsule_SetName:distinct:
PyCapsule_SetDestructor:distinct:
PyCapsule_SetContext:distinct:
# Import - looks up a capsule from a module attribute and
# calls PyCapsule_GetPointer; may call arbitrary code
PyCapsule_Import:compatible:
# Tuple objects
# Creation - pure allocation, no shared state
PyTuple_New:atomic:
PyTuple_FromArray:atomic:
PyTuple_Pack:atomic:
# Size - tuples are immutable so size never changes
PyTuple_Size:atomic:
PyTuple_GET_SIZE:atomic:
# Borrowed-reference lookups - tuples are immutable so items
# never change, however the tuple must be kept alive while using the borrowed reference
PyTuple_GetItem:compatible:
PyTuple_GET_ITEM:compatible:
# Slice - creates a new tuple from an existing tuple
PyTuple_GetSlice:atomic:
# SetItem - only usable on tuples with refcount 1
PyTuple_SetItem:compatible:
PyTuple_SET_ITEM:compatible:
# Resize - only usable on tuples with refcount 1
_PyTuple_Resize:compatible:
# Struct Sequence objects
# Creation
PyStructSequence_NewType:atomic:
PyStructSequence_New:atomic:
# Initialization - modifies the type object in place
PyStructSequence_InitType:distinct:
PyStructSequence_InitType2:distinct:
# Borrowed-reference lookups - same as tuple items
PyStructSequence_GetItem:compatible:
PyStructSequence_GET_ITEM:compatible:
# SetItem - only for filling in brand new instances
PyStructSequence_SetItem:compatible:
PyStructSequence_SET_ITEM:compatible:

2
Doc/deprecations/c-api-pending-removal-in-3.15.rst
View file

@ -7,8 +7,6 @@ Pending removal in Python 3.15
Use :c:func:`PyWeakref_GetRef` instead. The `pythoncapi-compat project
<https://github.com/python/pythoncapi-compat/>`__ can be used to get
:c:func:`PyWeakref_GetRef` on Python 3.12 and older.
* :c:type:`Py_UNICODE` type and the :c:macro:`!Py_UNICODE_WIDE` macro:
Use :c:type:`wchar_t` instead.
* :c:func:`!PyUnicode_AsDecodedObject`:
Use :c:func:`PyCodec_Decode` instead.
* :c:func:`!PyUnicode_AsDecodedUnicode`:

4
Doc/deprecations/c-api-pending-removal-in-3.19.rst Normal file
View file

@ -0,0 +1,4 @@
Pending removal in Python 3.19
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
* :pep:`456` embedders support for the string hashing scheme definition.

6
Doc/deprecations/index.rst
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@ -15,13 +15,19 @@ Deprecations
.. include:: pending-removal-in-future.rst
.. include:: soft-deprecations.rst
C API deprecations
------------------
.. include:: c-api-pending-removal-in-3.15.rst
.. include:: c-api-pending-removal-in-3.16.rst
.. include:: c-api-pending-removal-in-3.18.rst
.. include:: c-api-pending-removal-in-3.19.rst
.. include:: c-api-pending-removal-in-3.20.rst
.. include:: c-api-pending-removal-in-future.rst

4
Doc/deprecations/pending-removal-in-3.15.rst
View file

@ -54,13 +54,13 @@ Pending removal in Python 3.15
* :func:`~threading.RLock` will take no arguments in Python 3.15.
Passing any arguments has been deprecated since Python 3.14,
as the Python version does not permit any arguments,
as the Python version does not permit any arguments,
but the C version allows any number of positional or keyword arguments,
ignoring every argument.
* :mod:`types`:
* :class:`types.CodeType`: Accessing :attr:`~codeobject.co_lnotab` was
* :class:`types.CodeType`: Accessing :attr:`!codeobject.co_lnotab` was
deprecated in :pep:`626`
since 3.10 and was planned to be removed in 3.12,
but it only got a proper :exc:`DeprecationWarning` in 3.12.

10
Doc/deprecations/pending-removal-in-3.17.rst
View file

@ -1,6 +1,14 @@
Pending removal in Python 3.17
------------------------------
* :mod:`datetime`:
* :meth:`~datetime.datetime.strptime` calls using a format string containing
``%e`` (day of month) without a year.
This has been deprecated since Python 3.15.
(Contributed by Stan Ulbrych in :gh:`70647`.)
* :mod:`collections.abc`:
- :class:`collections.abc.ByteString` is scheduled for removal in Python 3.17.
@ -27,7 +35,7 @@ Pending removal in Python 3.17
- Passing non-ascii *encoding* names to :func:`encodings.normalize_encoding`
is deprecated and scheduled for removal in Python 3.17.
(Contributed by Stan Ulbrych in :gh:`136702`)
(Contributed by Stan Ulbrych in :gh:`136702`.)
* :mod:`typing`:

3
Doc/deprecations/pending-removal-in-3.18.rst
View file

@ -1,6 +1,9 @@
Pending removal in Python 3.18
------------------------------
* No longer accept a boolean value when a file descriptor is expected.
(Contributed by Serhiy Storchaka in :gh:`82626`.)
* :mod:`decimal`:
* The non-standard and undocumented :class:`~decimal.Decimal` format

8
Doc/deprecations/pending-removal-in-3.20.rst
View file

@ -1,6 +1,13 @@
Pending removal in Python 3.20
------------------------------
* Calling the ``__new__()`` method of :class:`struct.Struct` without the
*format* argument is deprecated and will be removed in Python 3.20. Calling
:meth:`~object.__init__` method on initialized :class:`~struct.Struct`
objects is deprecated and will be removed in Python 3.20.
(Contributed by Sergey B Kirpichev and Serhiy Storchaka in :gh:`143715`.)
* The ``__version__``, ``version`` and ``VERSION`` attributes have been
deprecated in these standard library modules and will be removed in
Python 3.20. Use :py:data:`sys.version_info` instead.
@ -21,6 +28,7 @@ Pending removal in Python 3.20
- :mod:`re`
- :mod:`socketserver`
- :mod:`tabnanny`
- :mod:`tarfile`
- :mod:`tkinter.font`
- :mod:`tkinter.ttk`
- :mod:`wsgiref.simple_server`

11
Doc/deprecations/pending-removal-in-future.rst
View file

@ -35,7 +35,6 @@ although there is currently no date scheduled for their removal.
* Support for ``__complex__()`` method returning a strict subclass of
:class:`complex`: these methods will be required to return an instance of
:class:`complex`.
* Delegation of ``int()`` to ``__trunc__()`` method.
* Passing a complex number as the *real* or *imag* argument in the
:func:`complex` constructor is now deprecated; it should only be passed
as a single positional argument.
@ -48,7 +47,7 @@ although there is currently no date scheduled for their removal.
* :mod:`codecs`: use :func:`open` instead of :func:`codecs.open`. (:gh:`133038`)
* :attr:`codeobject.co_lnotab`: use the :meth:`codeobject.co_lines` method
* :attr:`!codeobject.co_lnotab`: use the :meth:`codeobject.co_lines` method
instead.
* :mod:`datetime`:
@ -78,6 +77,14 @@ although there is currently no date scheduled for their removal.
* :mod:`os`: Calling :func:`os.register_at_fork` in a multi-threaded process.
* :mod:`os.path`: :func:`os.path.commonprefix` is deprecated, use
:func:`os.path.commonpath` for path prefixes. The :func:`os.path.commonprefix`
function is being deprecated due to having a misleading name and module.
The function is not safe to use for path prefixes despite being included in a
module about path manipulation, meaning it is easy to accidentally
introduce path traversal vulnerabilities into Python programs by using this
function.
* :class:`!pydoc.ErrorDuringImport`: A tuple value for *exc_info* parameter is
deprecated, use an exception instance.

21
Doc/deprecations/soft-deprecations.rst Normal file
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@ -0,0 +1,21 @@
Soft deprecations
-----------------
There are no plans to remove :term:`soft deprecated` APIs.
* :func:`re.match` and :meth:`re.Pattern.match` are now
:term:`soft deprecated` in favor of the new :func:`re.prefixmatch` and
:meth:`re.Pattern.prefixmatch` APIs, which have been added as alternate,
more explicit names. These are intended to be used to alleviate confusion
around what *match* means by following the Zen of Python's *"Explicit is
better than implicit"* mantra. Most other language regular expression
libraries use an API named *match* to mean what Python has always called
*search*.
We **do not** plan to remove the older :func:`!match` name, as it has been
used in code for over 30 years. Code supporting older versions of Python
should continue to use :func:`!match`, while new code should prefer
:func:`!prefixmatch`. See :ref:`prefixmatch-vs-match`.
(Contributed by Gregory P. Smith in :gh:`86519` and
Hugo van Kemenade in :gh:`148100`.)

3
Doc/extending/extending.rst
View file

@ -903,9 +903,6 @@ define this symbol).
Providing a C API for an Extension Module
=========================================
.. sectionauthor:: Konrad Hinsen <hinsen@cnrs-orleans.fr>
Many extension modules just provide new functions and types to be used from
Python, but sometimes the code in an extension module can be useful for other
extension modules. For example, an extension module could implement a type

7
Doc/extending/first-extension-module.rst
View file

@ -265,12 +265,19 @@ Define this array just before your export hook:
.. code-block:: c
PyABIInfo_VAR(abi_info);
static PyModuleDef_Slot spam_slots[] = {
{Py_mod_abi, &abi_info},
{Py_mod_name, "spam"},
{Py_mod_doc, "A wonderful module with an example function"},
{0, NULL}
};
The ``PyABIInfo_VAR(abi_info);`` macro and the :c:data:`Py_mod_abi` slot
are a bit of boilerplate that helps prevent extensions compiled for
a different version of Python from crashing the interpreter.
For both :c:data:`Py_mod_name` and :c:data:`Py_mod_doc`, the values are C
strings -- that is, NUL-terminated, UTF-8 encoded byte arrays.

5
Doc/extending/newtypes_tutorial.rst
View file

@ -6,11 +6,6 @@
Defining Extension Types: Tutorial
**********************************
.. sectionauthor:: Michael Hudson <mwh@python.net>
.. sectionauthor:: Dave Kuhlman <dkuhlman@rexx.com>
.. sectionauthor:: Jim Fulton <jim@zope.com>
Python allows the writer of a C extension module to define new types that
can be manipulated from Python code, much like the built-in :class:`str`
and :class:`list` types. The code for all extension types follows a

6
Doc/extending/windows.rst
View file

@ -47,9 +47,6 @@ things manually, it may be instructive to study the project file for the
Differences Between Unix and Windows
====================================
.. sectionauthor:: Chris Phoenix <cphoenix@best.com>
Unix and Windows use completely different paradigms for run-time loading of
code. Before you try to build a module that can be dynamically loaded, be aware
of how your system works.
@ -109,9 +106,6 @@ separate copy.
Using DLLs in Practice
======================
.. sectionauthor:: Chris Phoenix <cphoenix@best.com>
Windows Python is built in Microsoft Visual C++; using other compilers may or
may not work. The rest of this section is MSVC++ specific.

132
Doc/faq/programming.rst
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@ -8,11 +8,11 @@ Programming FAQ
.. contents::
General Questions
General questions
=================
Is there a source code level debugger with breakpoints, single-stepping, etc.?
------------------------------------------------------------------------------
Is there a source code-level debugger with breakpoints and single-stepping?
---------------------------------------------------------------------------
Yes.
@ -25,8 +25,7 @@ Reference Manual <pdb>`. You can also write your own debugger by using the code
for pdb as an example.
The IDLE interactive development environment, which is part of the standard
Python distribution (normally available as
`Tools/scripts/idle3 <https://github.com/python/cpython/blob/main/Tools/scripts/idle3>`_),
Python distribution (normally available as :mod:`idlelib`),
includes a graphical debugger.
PythonWin is a Python IDE that includes a GUI debugger based on pdb. The
@ -48,7 +47,6 @@ There are a number of commercial Python IDEs that include graphical debuggers.
They include:
* `Wing IDE <https://wingware.com/>`_
* `Komodo IDE <https://www.activestate.com/products/komodo-ide/>`_
* `PyCharm <https://www.jetbrains.com/pycharm/>`_
@ -57,13 +55,15 @@ Are there tools to help find bugs or perform static analysis?
Yes.
`Pylint <https://pylint.pycqa.org/en/latest/index.html>`_ and
`Pyflakes <https://github.com/PyCQA/pyflakes>`_ do basic checking that will
`Ruff <https://docs.astral.sh/ruff/>`__,
`Pylint <https://pylint.readthedocs.io/>`__ and
`Pyflakes <https://github.com/PyCQA/pyflakes>`__ do basic checking that will
help you catch bugs sooner.
Static type checkers such as `Mypy <https://mypy-lang.org/>`_,
`Pyre <https://pyre-check.org/>`_, and
`Pytype <https://github.com/google/pytype>`_ can check type hints in Python
Static type checkers such as `mypy <https://mypy-lang.org/>`__,
`ty <https://docs.astral.sh/ty/>`__,
`Pyrefly <https://pyrefly.org/>`__, and
`pytype <https://github.com/google/pytype>`__ can check type hints in Python
source code.
@ -79,7 +79,7 @@ set of modules required by a program and bind these modules together with a
Python binary to produce a single executable.
One is to use the freeze tool, which is included in the Python source tree as
`Tools/freeze <https://github.com/python/cpython/tree/main/Tools/freeze>`_.
:source:`Tools/freeze`.
It converts Python byte code to C arrays; with a C compiler you can
embed all your modules into a new program, which is then linked with the
standard Python modules.
@ -103,6 +103,7 @@ executables:
* `py2app <https://github.com/ronaldoussoren/py2app>`_ (macOS only)
* `py2exe <https://www.py2exe.org/>`_ (Windows only)
Are there coding standards or a style guide for Python programs?
----------------------------------------------------------------
@ -110,7 +111,7 @@ Yes. The coding style required for standard library modules is documented as
:pep:`8`.
Core Language
Core language
=============
.. _faq-unboundlocalerror:
@ -143,7 +144,7 @@ results in an :exc:`!UnboundLocalError`:
>>> foo()
Traceback (most recent call last):
...
UnboundLocalError: local variable 'x' referenced before assignment
UnboundLocalError: cannot access local variable 'x' where it is not associated with a value
This is because when you make an assignment to a variable in a scope, that
variable becomes local to that scope and shadows any similarly named variable
@ -208,7 +209,7 @@ Why do lambdas defined in a loop with different values all return the same resul
----------------------------------------------------------------------------------
Assume you use a for loop to define a few different lambdas (or even plain
functions), e.g.::
functions), for example::
>>> squares = []
>>> for x in range(5):
@ -227,7 +228,7 @@ they all return ``16``::
This happens because ``x`` is not local to the lambdas, but is defined in
the outer scope, and it is accessed when the lambda is called --- not when it
is defined. At the end of the loop, the value of ``x`` is ``4``, so all the
functions now return ``4**2``, i.e. ``16``. You can also verify this by
functions now return ``4**2``, that is ``16``. You can also verify this by
changing the value of ``x`` and see how the results of the lambdas change::
>>> x = 8
@ -298,9 +299,9 @@ using multiple imports per line uses less screen space.
It's good practice if you import modules in the following order:
1. standard library modules -- e.g. :mod:`sys`, :mod:`os`, :mod:`argparse`, :mod:`re`
1. standard library modules -- such as :mod:`sys`, :mod:`os`, :mod:`argparse`, :mod:`re`
2. third-party library modules (anything installed in Python's site-packages
directory) -- e.g. :mod:`!dateutil`, :mod:`!requests`, :mod:`!PIL.Image`
directory) -- such as :pypi:`dateutil`, :pypi:`requests`, :pypi:`tzdata`
3. locally developed modules
It is sometimes necessary to move imports to a function or class to avoid
@ -494,11 +495,11 @@ new objects).
In other words:
* If we have a mutable object (:class:`list`, :class:`dict`, :class:`set`,
etc.), we can use some specific operations to mutate it and all the variables
* If we have a mutable object (such as :class:`list`, :class:`dict`, :class:`set`),
we can use some specific operations to mutate it and all the variables
that refer to it will see the change.
* If we have an immutable object (:class:`str`, :class:`int`, :class:`tuple`,
etc.), all the variables that refer to it will always see the same value,
* If we have an immutable object (such as :class:`str`, :class:`int`, :class:`tuple`),
all the variables that refer to it will always see the same value,
but operations that transform that value into a new value always return a new
object.
@ -511,7 +512,7 @@ How do I write a function with output parameters (call by reference)?
Remember that arguments are passed by assignment in Python. Since assignment
just creates references to objects, there's no alias between an argument name in
the caller and callee, and so no call-by-reference per se. You can achieve the
the caller and callee, and consequently no call-by-reference. You can achieve the
desired effect in a number of ways.
1) By returning a tuple of the results::
@ -714,8 +715,8 @@ not::
"a" in ("b", "a")
The same is true of the various assignment operators (``=``, ``+=`` etc). They
are not truly operators but syntactic delimiters in assignment statements.
The same is true of the various assignment operators (``=``, ``+=``, and so on).
They are not truly operators but syntactic delimiters in assignment statements.
Is there an equivalent of C's "?:" ternary operator?
@ -868,9 +869,9 @@ with either a space or parentheses.
How do I convert a string to a number?
--------------------------------------
For integers, use the built-in :func:`int` type constructor, e.g. ``int('144')
For integers, use the built-in :func:`int` type constructor, for example, ``int('144')
== 144``. Similarly, :func:`float` converts to a floating-point number,
e.g. ``float('144') == 144.0``.
for example, ``float('144') == 144.0``.
By default, these interpret the number as decimal, so that ``int('0144') ==
144`` holds true, and ``int('0x144')`` raises :exc:`ValueError`. ``int(string,
@ -887,18 +888,18 @@ unwanted side effects. For example, someone could pass
directory.
:func:`eval` also has the effect of interpreting numbers as Python expressions,
so that e.g. ``eval('09')`` gives a syntax error because Python does not allow
so that, for example, ``eval('09')`` gives a syntax error because Python does not allow
leading '0' in a decimal number (except '0').
How do I convert a number to a string?
--------------------------------------
To convert, e.g., the number ``144`` to the string ``'144'``, use the built-in type
For example, to convert the number ``144`` to the string ``'144'``, use the built-in type
constructor :func:`str`. If you want a hexadecimal or octal representation, use
the built-in functions :func:`hex` or :func:`oct`. For fancy formatting, see
the :ref:`f-strings` and :ref:`formatstrings` sections,
e.g. ``"{:04d}".format(144)`` yields
the :ref:`f-strings` and :ref:`formatstrings` sections.
For example, ``"{:04d}".format(144)`` yields
``'0144'`` and ``"{:.3f}".format(1.0/3.0)`` yields ``'0.333'``.
@ -908,7 +909,7 @@ How do I modify a string in place?
You can't, because strings are immutable. In most situations, you should
simply construct a new string from the various parts you want to assemble
it from. However, if you need an object with the ability to modify in-place
unicode data, try using an :class:`io.StringIO` object or the :mod:`array`
Unicode data, try using an :class:`io.StringIO` object or the :mod:`array`
module::
>>> import io
@ -1066,13 +1067,14 @@ the raw string::
Also see the specification in the :ref:`language reference <strings>`.
Performance
===========
My program is too slow. How do I speed it up?
---------------------------------------------
That's a tough one, in general. First, here are a list of things to
That's a tough one, in general. First, here is a list of things to
remember before diving further:
* Performance characteristics vary across Python implementations. This FAQ
@ -1125,6 +1127,7 @@ yourself.
The wiki page devoted to `performance tips
<https://wiki.python.org/moin/PythonSpeed/PerformanceTips>`_.
.. _efficient_string_concatenation:
What is the most efficient way to concatenate many strings together?
@ -1143,7 +1146,7 @@ them into a list and call :meth:`str.join` at the end::
chunks.append(s)
result = ''.join(chunks)
(another reasonably efficient idiom is to use :class:`io.StringIO`)
(Another reasonably efficient idiom is to use :class:`io.StringIO`.)
To accumulate many :class:`bytes` objects, the recommended idiom is to extend
a :class:`bytearray` object using in-place concatenation (the ``+=`` operator)::
@ -1153,7 +1156,7 @@ a :class:`bytearray` object using in-place concatenation (the ``+=`` operator)::
result += b
Sequences (Tuples/Lists)
Sequences (tuples/lists)
========================
How do I convert between tuples and lists?
@ -1217,8 +1220,8 @@ list, deleting duplicates as you go::
else:
last = mylist[i]
If all elements of the list may be used as set keys (i.e. they are all
:term:`hashable`) this is often faster ::
If all elements of the list may be used as set keys (that is, they are all
:term:`hashable`) this is often faster::
mylist = list(set(mylist))
@ -1254,7 +1257,7 @@ difference is that a Python list can contain objects of many different types.
The ``array`` module also provides methods for creating arrays of fixed types
with compact representations, but they are slower to index than lists. Also
note that `NumPy <https://numpy.org/>`_
and other third party packages define array-like structures with
and other third-party packages define array-like structures with
various characteristics as well.
To get Lisp-style linked lists, you can emulate *cons cells* using tuples::
@ -1324,7 +1327,7 @@ Or, you can use an extension that provides a matrix datatype; `NumPy
How do I apply a method or function to a sequence of objects?
-------------------------------------------------------------
To call a method or function and accumulate the return values is a list,
To call a method or function and accumulate the return values in a list,
a :term:`list comprehension` is an elegant solution::
result = [obj.method() for obj in mylist]
@ -1340,6 +1343,7 @@ a plain :keyword:`for` loop will suffice::
for obj in mylist:
function(obj)
.. _faq-augmented-assignment-tuple-error:
Why does a_tuple[i] += ['item'] raise an exception when the addition works?
@ -1444,7 +1448,7 @@ How can I sort one list by values from another list?
----------------------------------------------------
Merge them into an iterator of tuples, sort the resulting list, and then pick
out the element you want. ::
out the element you want.
>>> list1 = ["what", "I'm", "sorting", "by"]
>>> list2 = ["something", "else", "to", "sort"]
@ -1504,14 +1508,15 @@ How do I check if an object is an instance of a given class or of a subclass of
Use the built-in function :func:`isinstance(obj, cls) <isinstance>`. You can
check if an object
is an instance of any of a number of classes by providing a tuple instead of a
single class, e.g. ``isinstance(obj, (class1, class2, ...))``, and can also
check whether an object is one of Python's built-in types, e.g.
single class, for example, ``isinstance(obj, (class1, class2, ...))``, and can also
check whether an object is one of Python's built-in types, for example,
``isinstance(obj, str)`` or ``isinstance(obj, (int, float, complex))``.
Note that :func:`isinstance` also checks for virtual inheritance from an
:term:`abstract base class`. So, the test will return ``True`` for a
registered class even if hasn't directly or indirectly inherited from it. To
test for "true inheritance", scan the :term:`MRO` of the class:
test for "true inheritance", scan the :term:`method resolution order` (MRO) of
the class:
.. testcode::
@ -1574,7 +1579,7 @@ call it::
What is delegation?
-------------------
Delegation is an object oriented technique (also called a design pattern).
Delegation is an object-oriented technique (also called a design pattern).
Let's say you have an object ``x`` and want to change the behaviour of just one
of its methods. You can create a new class that provides a new implementation
of the method you're interested in changing and delegates all other methods to
@ -1645,7 +1650,7 @@ How can I organize my code to make it easier to change the base class?
You could assign the base class to an alias and derive from the alias. Then all
you have to change is the value assigned to the alias. Incidentally, this trick
is also handy if you want to decide dynamically (e.g. depending on availability
is also handy if you want to decide dynamically (such as depending on availability
of resources) which base class to use. Example::
class Base:
@ -1710,9 +1715,9 @@ How can I overload constructors (or methods) in Python?
This answer actually applies to all methods, but the question usually comes up
first in the context of constructors.
In C++ you'd write
In C++ you'd write:
.. code-block:: c
.. code-block:: c++
class C {
C() { cout << "No arguments\n"; }
@ -1731,7 +1736,7 @@ default arguments. For example::
This is not entirely equivalent, but close enough in practice.
You could also try a variable-length argument list, e.g. ::
You could also try a variable-length argument list, for example::
def __init__(self, *args):
...
@ -1774,6 +1779,7 @@ to use private variable names at all.
The :ref:`private name mangling specifications <private-name-mangling>`
for details and special cases.
My class defines __del__ but it is not called when I delete the object.
-----------------------------------------------------------------------
@ -1783,7 +1789,7 @@ The :keyword:`del` statement does not necessarily call :meth:`~object.__del__` -
decrements the object's reference count, and if this reaches zero
:meth:`!__del__` is called.
If your data structures contain circular links (e.g. a tree where each child has
If your data structures contain circular links (for example, a tree where each child has
a parent reference and each parent has a list of children) the reference counts
will never go back to zero. Once in a while Python runs an algorithm to detect
such cycles, but the garbage collector might run some time after the last
@ -1852,6 +1858,8 @@ to the object:
13891296
.. _faq-identity-with-is:
When can I rely on identity tests with the *is* operator?
---------------------------------------------------------
@ -1883,9 +1891,9 @@ are preferred. In particular, identity tests should not be used to check
constants such as :class:`int` and :class:`str` which aren't guaranteed to be
singletons::
>>> a = 1000
>>> b = 500
>>> c = b + 500
>>> a = 10_000_000
>>> b = 5_000_000
>>> c = b + 5_000_000
>>> a is c
False
@ -1954,9 +1962,9 @@ parent class:
.. testcode::
from datetime import date
import datetime as dt
class FirstOfMonthDate(date):
class FirstOfMonthDate(dt.date):
"Always choose the first day of the month"
def __new__(cls, year, month, day):
return super().__new__(cls, year, month, 1)
@ -1999,7 +2007,7 @@ The two principal tools for caching methods are
former stores results at the instance level and the latter at the class
level.
The *cached_property* approach only works with methods that do not take
The ``cached_property`` approach only works with methods that do not take
any arguments. It does not create a reference to the instance. The
cached method result will be kept only as long as the instance is alive.
@ -2008,7 +2016,7 @@ method result will be released right away. The disadvantage is that if
instances accumulate, so too will the accumulated method results. They
can grow without bound.
The *lru_cache* approach works with methods that have :term:`hashable`
The ``lru_cache`` approach works with methods that have :term:`hashable`
arguments. It creates a reference to the instance unless special
efforts are made to pass in weak references.
@ -2042,11 +2050,11 @@ This example shows the various techniques::
# Depends on the station_id, date, and units.
The above example assumes that the *station_id* never changes. If the
relevant instance attributes are mutable, the *cached_property* approach
relevant instance attributes are mutable, the ``cached_property`` approach
can't be made to work because it cannot detect changes to the
attributes.
To make the *lru_cache* approach work when the *station_id* is mutable,
To make the ``lru_cache`` approach work when the *station_id* is mutable,
the class needs to define the :meth:`~object.__eq__` and :meth:`~object.__hash__`
methods so that the cache can detect relevant attribute updates::
@ -2092,10 +2100,10 @@ one user but run as another, such as if you are testing with a web server.
Unless the :envvar:`PYTHONDONTWRITEBYTECODE` environment variable is set,
creation of a .pyc file is automatic if you're importing a module and Python
has the ability (permissions, free space, etc...) to create a ``__pycache__``
has the ability (permissions, free space, and so on) to create a ``__pycache__``
subdirectory and write the compiled module to that subdirectory.
Running Python on a top level script is not considered an import and no
Running Python on a top-level script is not considered an import and no
``.pyc`` will be created. For example, if you have a top-level module
``foo.py`` that imports another module ``xyz.py``, when you run ``foo`` (by
typing ``python foo.py`` as a shell command), a ``.pyc`` will be created for
@ -2114,7 +2122,7 @@ the ``compile()`` function in that module interactively::
This will write the ``.pyc`` to a ``__pycache__`` subdirectory in the same
location as ``foo.py`` (or you can override that with the optional parameter
``cfile``).
*cfile*).
You can also automatically compile all files in a directory or directories using
the :mod:`compileall` module. You can do it from the shell prompt by running
@ -2219,7 +2227,7 @@ changed module, do this::
importlib.reload(modname)
Warning: this technique is not 100% fool-proof. In particular, modules
containing statements like ::
containing statements like::
from modname import some_objects

22
Doc/glossary.rst
View file

@ -951,6 +951,16 @@ Glossary
to locks exist such as queues, producer/consumer patterns, and
thread-local state. See also :term:`deadlock`, and :term:`reentrant`.
lock-free
An operation that does not acquire any :term:`lock` and uses atomic CPU
instructions to ensure correctness. Lock-free operations can execute
concurrently without blocking each other and cannot be blocked by
operations that hold locks. In :term:`free-threaded <free threading>`
Python, built-in types like :class:`dict` and :class:`list` provide
lock-free read operations, which means other threads may observe
intermediate states during multi-step modifications even when those
modifications hold the :term:`per-object lock`.
loader
An object that loads a module.
It must define the :meth:`!exec_module` and :meth:`!create_module` methods
@ -1217,6 +1227,16 @@ Glossary
<faq-argument-vs-parameter>`, the :class:`inspect.Parameter` class, the
:ref:`function` section, and :pep:`362`.
per-object lock
A :term:`lock` associated with an individual object instance rather than
a global lock shared across all objects. In :term:`free-threaded
<free threading>` Python, built-in types like :class:`dict` and
:class:`list` use per-object locks to allow concurrent operations on
different objects while serializing operations on the same object.
Operations that hold the per-object lock prevent other locking operations
on the same object from proceeding, but do not block :term:`lock-free`
operations.
path entry
A single location on the :term:`import path` which the :term:`path
based finder` consults to find modules for importing.
@ -1339,7 +1359,7 @@ Glossary
'email.mime.text'
race condition
A condition of a program where the its behavior
A condition of a program where the behavior
depends on the relative timing or ordering of events, particularly in
multi-threaded programs. Race conditions can lead to
:term:`non-deterministic` behavior and bugs that are difficult to

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