gh-102304: doc: Add links to Stable ABI and Limited C API (#105345)

* Add "limited-c-api" and "stable-api" references.
* Rename "stable-abi-list" reference to "limited-api-list".
* Makefile: Document files regenerated by "make regen-limited-abi"
* Remove first empty line in generated files:

  - Lib/test/test_stable_abi_ctypes.py
  - PC/python3dll.c
This commit is contained in:
Victor Stinner 2023-06-06 10:40:32 +02:00 • committed by GitHub
parent 00d73caf80
commit bae415ad02
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
17 changed files with 58 additions and 42 deletions

View file

@ -887,7 +887,7 @@ because the :ref:`call protocol <call>` takes care of recursion handling.
depth limit.
.. versionchanged:: 3.9
This function is now also available in the limited API.
This function is now also available in the :ref:`limited API <limited-c-api>`.
.. c:function:: void Py_LeaveRecursiveCall(void)
@ -895,7 +895,7 @@ because the :ref:`call protocol <call>` takes care of recursion handling.
*successful* invocation of :c:func:`Py_EnterRecursiveCall`.
.. versionchanged:: 3.9
This function is now also available in the limited API.
This function is now also available in the :ref:`limited API <limited-c-api>`.
Properly implementing :c:member:`~PyTypeObject.tp_repr` for container types requires
special recursion handling. In addition to protecting the stack,

View file

@ -20,9 +20,9 @@ but will need to be compiled separately for 3.9.x and 3.10.x.
There are two tiers of C API with different stability exepectations:
- *Unstable API*, may change in minor versions without a deprecation period.
It is marked by the ``PyUnstable`` prefix in names.
- *Limited API*, is compatible across several minor releases.
- :ref:`Unstable API <unstable-c-api>`, may change in minor versions without
a deprecation period. It is marked by the ``PyUnstable`` prefix in names.
- :ref:`Limited API <limited-c-api>`, is compatible across several minor releases.
When :c:macro:`Py_LIMITED_API` is defined, only this subset is exposed
from ``Python.h``.
@ -55,19 +55,15 @@ CPython development and spend extra effort adjusting to changes.
Stable Application Binary Interface
===================================
.. _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 work with multiple versions of Python.
Contents of the Limited API are :ref:`listed below <stable-abi-list>`.
To enable this, Python provides a *Stable ABI*: a set of symbols that will
remain compatible across Python 3.x versions. The Stable ABI contains symbols
exposed in the Limited API, but also other ones – for example, functions
necessary to support older versions of the Limited API.
(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.)
Contents of the Limited API are :ref:`listed below <limited-api-list>`.
.. c:macro:: Py_LIMITED_API
@ -87,6 +83,23 @@ embedding Python.)
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 compatible across Python 3.x versions.
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.
(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.)
On Windows, extensions that use the Stable ABI should be linked against
``python3.dll`` rather than a version-specific library such as
``python39.dll``.
@ -131,9 +144,9 @@ Limited API Caveats
-------------------
Note that compiling with ``Py_LIMITED_API`` is *not* a complete guarantee that
code conforms to the Limited API or the Stable ABI. ``Py_LIMITED_API`` only
covers definitions, but an API also includes other issues, such as expected
semantics.
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.
One issue that ``Py_LIMITED_API`` does not guard against is calling a function
with arguments that are invalid in a lower Python version.
@ -166,9 +179,9 @@ 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 Stable ABI,
these details define a “platform”. They usually depend on the OS
type and processor architecture
lower-level libraries and compiler options. For the purposes of
the :ref:`Stable ABI <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
@ -177,12 +190,12 @@ This is the case with Windows and macOS releases from ``python.org`` and many
third-party distributors.
.. _stable-abi-list:
.. _limited-api-list:
Contents of Limited API
=======================
Currently, the Limited API includes the following items:
Currently, the :ref:`Limited API <limited-c-api>` includes the following items:
.. limited-api-list::

View file

@ -288,7 +288,7 @@ There are these calling conventions:
.. versionchanged:: 3.10
``METH_FASTCALL`` is now part of the stable ABI.
``METH_FASTCALL`` is now part of the :ref:`stable ABI <stable-abi>`.
.. data:: METH_FASTCALL | METH_KEYWORDS

View file

@ -42,7 +42,7 @@ Type Objects
Return the :c:member:`~PyTypeObject.tp_flags` member of *type*. This function is primarily
meant for use with ``Py_LIMITED_API``; the individual flag bits are
guaranteed to be stable across Python releases, but access to
:c:member:`~PyTypeObject.tp_flags` itself is not part of the limited API.
:c:member:`~PyTypeObject.tp_flags` itself is not part of the :ref:`limited API <limited-c-api>`.
.. versionadded:: 3.2
@ -472,7 +472,7 @@ The following functions and structs are used to create
.. versionchanged:: 3.11
:c:member:`~PyBufferProcs.bf_getbuffer` and
:c:member:`~PyBufferProcs.bf_releasebuffer` are now available
under the limited API.
under the :ref:`limited API <limited-c-api>`.
.. c:member:: void *pfunc

View file

@ -2150,7 +2150,7 @@ This results in types that are limited relative to types defined in Python:
include any subinterpreter-specific state.
Also, since :c:type:`PyTypeObject` is only part of the :ref:`Limited API
<stable>` as an opaque struct, any extension modules using static types must be
<limited-c-api>` as an opaque struct, any extension modules using static types must be
compiled for a specific Python minor version.

View file

@ -994,7 +994,7 @@ These are the UTF-8 codec APIs:
The return type is now ``const char *`` rather of ``char *``.
.. versionchanged:: 3.10
This function is a part of the :ref:`limited API <stable>`.
This function is a part of the :ref:`limited API <limited-c-api>`.
.. c:function:: const char* PyUnicode_AsUTF8(PyObject *unicode)