Fix wheels for python 3.14 free thread

CHANGELOG.md

@@ -15,6 +15,7 @@ avoid adding features or APIs which do not map onto the
 [H3 core API](https://uber.github.io/h3/#/documentation/api-reference/).
 
 ## Unreleased
+- Fix wheels for Python 3.14.6 free-threading
 
 ## [4.5.0] - 2026-05-29
 

pyproject.toml

@@ -30,6 +30,7 @@ classifiers = [
     'Programming Language :: Python :: 3.12',
     'Programming Language :: Python :: 3.13',
     'Programming Language :: Python :: 3.14',
+    'Programming Language :: Python :: Free Threading',
     'Operating System :: MacOS :: MacOS X',
     'Operating System :: POSIX :: Linux',
     'Operating System :: Microsoft :: Windows',

src/h3/_cy/cells.pyx

@@ -1,3 +1,4 @@
+# cython: freethreading_compatible=True
 cimport h3lib
 from .h3lib cimport bool, int64_t, H3int, H3ErrorCodes
 

src/h3/_cy/edges.pyx

@@ -1,3 +1,4 @@
+# cython: freethreading_compatible=True
 cimport h3lib
 from .h3lib cimport bool, H3int
 

src/h3/_cy/error_system.pyx

@@ -1,3 +1,4 @@
+# cython: freethreading_compatible=True
 """
 Exceptions from the h3-py library have three possible sources:
 

src/h3/_cy/latlng.pyx

@@ -1,3 +1,4 @@
+# cython: freethreading_compatible=True
 from libc.stdint cimport uint64_t
 
 cimport h3lib

src/h3/_cy/memory.pyx

@@ -1,3 +1,4 @@
+# cython: freethreading_compatible=True
 from cython.view cimport array
 from .h3lib cimport H3int
 

src/h3/_cy/to_multipoly.pyx

@@ -1,3 +1,4 @@
+# cython: freethreading_compatible=True
 cimport h3lib
 from h3lib cimport H3int
 from .util cimport check_cell, coord2deg

src/h3/_cy/util.pyx

@@ -1,3 +1,4 @@
+# cython: freethreading_compatible=True
 from .h3lib cimport (
     H3int,
     H3str,

src/h3/_cy/vertex.pyx

@@ -1,3 +1,4 @@
+# cython: freethreading_compatible=True
 cimport h3lib
 from h3lib cimport bool, H3int