Update docs and whatsnew

python · zooba · Mar 19, 2025 · Mar 19, 2025 · Mar 19, 2025 · Mar 19, 2025
commit 548daa7592b4a896dd5aa07b4e9b96ff26d7145c
diff --git a/Doc/library/zlib.rst b/Doc/library/zlib.rst
@@ -330,6 +330,18 @@ the following constants:
    .. versionadded:: 3.3
 
 
+.. data:: ZLIBNG_VERSION
+
+   The version string of the zlib-ng library that was used for building the
+   module if zlib-ng was used. When present, the :data:`ZLIB_VERSION` and
+   :data:`ZLIB_RUNTIME_VERSION` constants reflect the version of the zlib API
+   provided by zlib-ng.
+
+   If zlib-ng was not used to build the module, this constant will be absent.
+
+   .. versionadded:: 3.14
+
+
 .. seealso::
 
    Module :mod:`gzip`

diff --git a/Doc/whatsnew/3.14.rst b/Doc/whatsnew/3.14.rst
@@ -1026,6 +1026,7 @@
   to produce reproducible output.
   (Contributed by Jiahao Li in :gh:`91279`.)
 
+
 .. Add improved modules above alphabetically, not here at the end.
 
 Optimizations
@@ -1078,6 +1079,18 @@
   (Contributed by Bénédikt Tran in :gh:`128150`.)
 
 
+zlib
+----
+
+* On Windows, ``zlib-ng`` is now used as the implementation of the
+  :mod:`zlib` module. This should produce compatible and comparable
+  results with better performance, though it is worth noting that
+  :const:`~zlib.Z_BEST_SPEED` (1) may result in significantly less
+  compression than the previous implementation (while also significantly
+  reducing the time taken to compress).
+  (Contributed by Steve Dower in :gh:`91349`.)
+
+
 Deprecated
 ==========