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gh-82909: Update PC/pyconfig.h to allow disabling pragma based auto-linking #19740

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Merged
zooba merged 5 commits into from
Mar 10, 2025
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gh-82909: Update PC/pyconfig.h to allow disabling pragma based auto-linking #19740

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56da8f9
bpo-38728: Update PC/pyconfig.h to allow disabling pragma based auto-…
jcfr Apr 27, 2020
7aa18a2
Add a news entry
arhadthedev Apr 2, 2023
29268cc
Add documentation
arhadthedev Apr 2, 2023
3658f4c
Rename PY_NO_LINK_LIB to Py_NO_LINK_LIB
arhadthedev Apr 2, 2023
23c9af6
Fix `WARNING: Literal block expected; none found`
arhadthedev Apr 2, 2023
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Rename PY_NO_LINK_LIB to Py_NO_LINK_LIB
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@arhadthedev @jcfr
arhadthedev authored and jcfr committed Mar 2, 2025
commit 3658f4c58ec268428dd00d1bd834df4192766a51
8 changes: 4 additions & 4 deletions Doc/extending/windows.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -96,7 +96,7 @@ gives you access to spam's names, but does not create a separate copy. On Unix,
linking with a library is more like ``from spam import *``; it does create a
separate copy.

.. c:macro:: PY_NO_LINK_LIB
.. c:macro:: Py_NO_LINK_LIB

Turn off the implicit, ``#pragma``-based linkage with the Python
library, performed inside CPython header files.
Expand Down Expand Up @@ -138,14 +138,14 @@ When creating DLLs in Windows, you can use the CPython library in two ways::
:file:`.lib`), which knows how to find the necessary functions from spam,
and also from the Python executable.

2. Manually by defining :c:macro:`PY_NO_LINK_LIB` macro before including
2. Manually by defining :c:macro:`Py_NO_LINK_LIB` macro before including
:file:`Python.h`. You must pass :file:`pythonXY.lib` to the linker.

To build two DLLs, spam and ni (which uses C functions found in spam), you
could use these commands::

cl /LD /DPY_NO_LINK_LIB /I/python/include spam.c ../libs/pythonXY.lib
cl /LD /DPY_NO_LINK_LIB /I/python/include ni.c spam.lib ../libs/pythonXY.lib
cl /LD /DPy_NO_LINK_LIB /I/python/include spam.c ../libs/pythonXY.lib
cl /LD /DPy_NO_LINK_LIB /I/python/include ni.c spam.lib ../libs/pythonXY.lib

The first command created three files: :file:`spam.obj`, :file:`spam.dll`
and :file:`spam.lib`. :file:`Spam.dll` does not contain any Python
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2 changes: 1 addition & 1 deletion Misc/NEWS.d/next/Build/2023-04-02-14-20-29.gh-issue-82909.LGcZJy.rst
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@@ -1,2 +1,2 @@
``#pragma``-based linking with ``python3*.lib`` can now be switched off with
:c:expr:`PY_NO_LINK_LIB`. Patch by Jean-Christophe Fillion-Robin.
:c:expr:`Py_NO_LINK_LIB`. Patch by Jean-Christophe Fillion-Robin.
6 changes: 3 additions & 3 deletions PC/pyconfig.h.in
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Expand Up @@ -311,10 +311,10 @@ Py_NO_ENABLE_SHARED to find out. Also support MS_NO_COREDLL for b/w compat */
#ifdef MS_COREDLL
# if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
/* not building the core - must be an ext */
# if defined(_MSC_VER) && !defined(PY_NO_LINK_LIB)
# if defined(_MSC_VER) && !defined(Py_NO_LINK_LIB)
/* So MSVC users need not specify the .lib
file in their Makefile */
/* Define PY_NO_LINK_LIB to build extension disabling pragma
/* Define Py_NO_LINK_LIB to build extension disabling pragma
based auto-linking.
This is relevant when using build-system generator (e.g CMake) where
the linking is explicitly handled */
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@zooba zooba Mar 3, 2025

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This comment isn't important for this file, though a short header above the entire block (something like "automatically reference python3x.lib") might make it easier to understand the purpose without reading the whole way through.

Expand All @@ -335,7 +335,7 @@ Py_NO_ENABLE_SHARED to find out. Also support MS_NO_COREDLL for b/w compat */
# pragma comment(lib,"python314.lib")
# endif /* _DEBUG */
# endif /* Py_GIL_DISABLED */
# endif /* _MSC_VER && !PY_NO_LINK_LIB */
# endif /* _MSC_VER && !Py_NO_LINK_LIB */
# endif /* Py_BUILD_CORE */
#endif /* MS_COREDLL */

Expand Down